1 /* ---------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2005
5 * The scheduler and thread-related functionality
7 * --------------------------------------------------------------------------*/
9 #include "PosixSource.h"
14 #include "BlockAlloc.h"
15 #include "OSThreads.h"
20 #include "StgMiscClosures.h"
21 #include "Interpreter.h"
22 #include "Exception.h"
24 #include "RtsSignals.h"
30 #include "ThreadLabels.h"
31 #include "LdvProfile.h"
34 #include "Proftimer.h"
37 #if defined(GRAN) || defined(PARALLEL_HASKELL)
38 # include "GranSimRts.h"
40 # include "ParallelRts.h"
41 # include "Parallel.h"
42 # include "ParallelDebug.h"
47 #include "Capability.h"
49 #include "AwaitEvent.h"
50 #if defined(mingw32_HOST_OS)
51 #include "win32/IOManager.h"
54 #ifdef HAVE_SYS_TYPES_H
55 #include <sys/types.h>
69 // Turn off inlining when debugging - it obfuscates things
72 # define STATIC_INLINE static
75 /* -----------------------------------------------------------------------------
77 * -------------------------------------------------------------------------- */
81 StgTSO* ActiveTSO = NULL; /* for assigning system costs; GranSim-Light only */
82 /* rtsTime TimeOfNextEvent, EndOfTimeSlice; now in GranSim.c */
85 In GranSim we have a runnable and a blocked queue for each processor.
86 In order to minimise code changes new arrays run_queue_hds/tls
87 are created. run_queue_hd is then a short cut (macro) for
88 run_queue_hds[CurrentProc] (see GranSim.h).
91 StgTSO *run_queue_hds[MAX_PROC], *run_queue_tls[MAX_PROC];
92 StgTSO *blocked_queue_hds[MAX_PROC], *blocked_queue_tls[MAX_PROC];
93 StgTSO *ccalling_threadss[MAX_PROC];
94 /* We use the same global list of threads (all_threads) in GranSim as in
95 the std RTS (i.e. we are cheating). However, we don't use this list in
96 the GranSim specific code at the moment (so we are only potentially
101 #if !defined(THREADED_RTS)
102 // Blocked/sleeping thrads
103 StgTSO *blocked_queue_hd = NULL;
104 StgTSO *blocked_queue_tl = NULL;
105 StgTSO *sleeping_queue = NULL; // perhaps replace with a hash table?
108 /* Threads blocked on blackholes.
109 * LOCK: sched_mutex+capability, or all capabilities
111 StgTSO *blackhole_queue = NULL;
114 /* The blackhole_queue should be checked for threads to wake up. See
115 * Schedule.h for more thorough comment.
116 * LOCK: none (doesn't matter if we miss an update)
118 rtsBool blackholes_need_checking = rtsFalse;
120 /* Linked list of all threads.
121 * Used for detecting garbage collected threads.
122 * LOCK: sched_mutex+capability, or all capabilities
124 StgTSO *all_threads = NULL;
126 /* flag set by signal handler to precipitate a context switch
127 * LOCK: none (just an advisory flag)
129 int context_switch = 0;
131 /* flag that tracks whether we have done any execution in this time slice.
132 * LOCK: currently none, perhaps we should lock (but needs to be
133 * updated in the fast path of the scheduler).
135 nat recent_activity = ACTIVITY_YES;
137 /* if this flag is set as well, give up execution
138 * LOCK: none (changes once, from false->true)
140 rtsBool sched_state = SCHED_RUNNING;
142 /* Next thread ID to allocate.
145 static StgThreadID next_thread_id = 1;
147 /* The smallest stack size that makes any sense is:
148 * RESERVED_STACK_WORDS (so we can get back from the stack overflow)
149 * + sizeofW(StgStopFrame) (the stg_stop_thread_info frame)
150 * + 1 (the closure to enter)
152 * + 1 (spare slot req'd by stg_ap_v_ret)
154 * A thread with this stack will bomb immediately with a stack
155 * overflow, which will increase its stack size.
157 #define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 3)
163 /* This is used in `TSO.h' and gcc 2.96 insists that this variable actually
164 * exists - earlier gccs apparently didn't.
170 * Set to TRUE when entering a shutdown state (via shutdownHaskellAndExit()) --
171 * in an MT setting, needed to signal that a worker thread shouldn't hang around
172 * in the scheduler when it is out of work.
174 rtsBool shutting_down_scheduler = rtsFalse;
177 * This mutex protects most of the global scheduler data in
178 * the THREADED_RTS runtime.
180 #if defined(THREADED_RTS)
184 #if defined(PARALLEL_HASKELL)
186 rtsTime TimeOfLastYield;
187 rtsBool emitSchedule = rtsTrue;
190 /* -----------------------------------------------------------------------------
191 * static function prototypes
192 * -------------------------------------------------------------------------- */
194 static Capability *schedule (Capability *initialCapability, Task *task);
197 // These function all encapsulate parts of the scheduler loop, and are
198 // abstracted only to make the structure and control flow of the
199 // scheduler clearer.
201 static void schedulePreLoop (void);
202 #if defined(THREADED_RTS)
203 static void schedulePushWork(Capability *cap, Task *task);
205 static void scheduleStartSignalHandlers (Capability *cap);
206 static void scheduleCheckBlockedThreads (Capability *cap);
207 static void scheduleCheckWakeupThreads(Capability *cap USED_IF_NOT_THREADS);
208 static void scheduleCheckBlackHoles (Capability *cap);
209 static void scheduleDetectDeadlock (Capability *cap, Task *task);
211 static StgTSO *scheduleProcessEvent(rtsEvent *event);
213 #if defined(PARALLEL_HASKELL)
214 static StgTSO *scheduleSendPendingMessages(void);
215 static void scheduleActivateSpark(void);
216 static rtsBool scheduleGetRemoteWork(rtsBool *receivedFinish);
218 #if defined(PAR) || defined(GRAN)
219 static void scheduleGranParReport(void);
221 static void schedulePostRunThread(void);
222 static rtsBool scheduleHandleHeapOverflow( Capability *cap, StgTSO *t );
223 static void scheduleHandleStackOverflow( Capability *cap, Task *task,
225 static rtsBool scheduleHandleYield( Capability *cap, StgTSO *t,
226 nat prev_what_next );
227 static void scheduleHandleThreadBlocked( StgTSO *t );
228 static rtsBool scheduleHandleThreadFinished( Capability *cap, Task *task,
230 static rtsBool scheduleDoHeapProfile(rtsBool ready_to_gc);
231 static Capability *scheduleDoGC(Capability *cap, Task *task,
233 void (*get_roots)(evac_fn));
235 static void unblockThread(Capability *cap, StgTSO *tso);
236 static rtsBool checkBlackHoles(Capability *cap);
237 static void AllRoots(evac_fn evac);
239 static StgTSO *threadStackOverflow(Capability *cap, StgTSO *tso);
241 static void raiseAsync_(Capability *cap, StgTSO *tso, StgClosure *exception,
242 rtsBool stop_at_atomically, StgPtr stop_here);
244 static void deleteThread (Capability *cap, StgTSO *tso);
245 static void deleteAllThreads (Capability *cap);
248 static void printThreadBlockage(StgTSO *tso);
249 static void printThreadStatus(StgTSO *tso);
250 void printThreadQueue(StgTSO *tso);
253 #if defined(PARALLEL_HASKELL)
254 StgTSO * createSparkThread(rtsSpark spark);
255 StgTSO * activateSpark (rtsSpark spark);
259 static char *whatNext_strs[] = {
269 /* -----------------------------------------------------------------------------
270 * Putting a thread on the run queue: different scheduling policies
271 * -------------------------------------------------------------------------- */
274 addToRunQueue( Capability *cap, StgTSO *t )
276 #if defined(PARALLEL_HASKELL)
277 if (RtsFlags.ParFlags.doFairScheduling) {
278 // this does round-robin scheduling; good for concurrency
279 appendToRunQueue(cap,t);
281 // this does unfair scheduling; good for parallelism
282 pushOnRunQueue(cap,t);
285 // this does round-robin scheduling; good for concurrency
286 appendToRunQueue(cap,t);
290 /* ---------------------------------------------------------------------------
291 Main scheduling loop.
293 We use round-robin scheduling, each thread returning to the
294 scheduler loop when one of these conditions is detected:
297 * timer expires (thread yields)
303 In a GranSim setup this loop iterates over the global event queue.
304 This revolves around the global event queue, which determines what
305 to do next. Therefore, it's more complicated than either the
306 concurrent or the parallel (GUM) setup.
309 GUM iterates over incoming messages.
310 It starts with nothing to do (thus CurrentTSO == END_TSO_QUEUE),
311 and sends out a fish whenever it has nothing to do; in-between
312 doing the actual reductions (shared code below) it processes the
313 incoming messages and deals with delayed operations
314 (see PendingFetches).
315 This is not the ugliest code you could imagine, but it's bloody close.
317 ------------------------------------------------------------------------ */
320 schedule (Capability *initialCapability, Task *task)
324 StgThreadReturnCode ret;
327 #elif defined(PARALLEL_HASKELL)
330 rtsBool receivedFinish = rtsFalse;
332 nat tp_size, sp_size; // stats only
337 #if defined(THREADED_RTS)
338 rtsBool first = rtsTrue;
341 cap = initialCapability;
343 // Pre-condition: this task owns initialCapability.
344 // The sched_mutex is *NOT* held
345 // NB. on return, we still hold a capability.
348 sched_belch("### NEW SCHEDULER LOOP (task: %p, cap: %p)",
349 task, initialCapability);
354 // -----------------------------------------------------------
355 // Scheduler loop starts here:
357 #if defined(PARALLEL_HASKELL)
358 #define TERMINATION_CONDITION (!receivedFinish)
360 #define TERMINATION_CONDITION ((event = get_next_event()) != (rtsEvent*)NULL)
362 #define TERMINATION_CONDITION rtsTrue
365 while (TERMINATION_CONDITION) {
368 /* Choose the processor with the next event */
369 CurrentProc = event->proc;
370 CurrentTSO = event->tso;
373 #if defined(THREADED_RTS)
375 // don't yield the first time, we want a chance to run this
376 // thread for a bit, even if there are others banging at the
379 ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
381 // Yield the capability to higher-priority tasks if necessary.
382 yieldCapability(&cap, task);
386 #if defined(THREADED_RTS)
387 schedulePushWork(cap,task);
390 // Check whether we have re-entered the RTS from Haskell without
391 // going via suspendThread()/resumeThread (i.e. a 'safe' foreign
393 if (cap->in_haskell) {
394 errorBelch("schedule: re-entered unsafely.\n"
395 " Perhaps a 'foreign import unsafe' should be 'safe'?");
396 stg_exit(EXIT_FAILURE);
399 // The interruption / shutdown sequence.
401 // In order to cleanly shut down the runtime, we want to:
402 // * make sure that all main threads return to their callers
403 // with the state 'Interrupted'.
404 // * clean up all OS threads assocated with the runtime
405 // * free all memory etc.
407 // So the sequence for ^C goes like this:
409 // * ^C handler sets sched_state := SCHED_INTERRUPTING and
410 // arranges for some Capability to wake up
412 // * all threads in the system are halted, and the zombies are
413 // placed on the run queue for cleaning up. We acquire all
414 // the capabilities in order to delete the threads, this is
415 // done by scheduleDoGC() for convenience (because GC already
416 // needs to acquire all the capabilities). We can't kill
417 // threads involved in foreign calls.
419 // * sched_state := SCHED_INTERRUPTED
421 // * somebody calls shutdownHaskell(), which calls exitScheduler()
423 // * sched_state := SCHED_SHUTTING_DOWN
425 // * all workers exit when the run queue on their capability
426 // drains. All main threads will also exit when their TSO
427 // reaches the head of the run queue and they can return.
429 // * eventually all Capabilities will shut down, and the RTS can
432 // * We might be left with threads blocked in foreign calls,
433 // we should really attempt to kill these somehow (TODO);
435 switch (sched_state) {
438 case SCHED_INTERRUPTING:
439 IF_DEBUG(scheduler, sched_belch("SCHED_INTERRUPTING"));
440 #if defined(THREADED_RTS)
441 discardSparksCap(cap);
443 /* scheduleDoGC() deletes all the threads */
444 cap = scheduleDoGC(cap,task,rtsFalse,GetRoots);
446 case SCHED_INTERRUPTED:
447 IF_DEBUG(scheduler, sched_belch("SCHED_INTERRUPTED"));
449 case SCHED_SHUTTING_DOWN:
450 IF_DEBUG(scheduler, sched_belch("SCHED_SHUTTING_DOWN"));
451 // If we are a worker, just exit. If we're a bound thread
452 // then we will exit below when we've removed our TSO from
454 if (task->tso == NULL && emptyRunQueue(cap)) {
459 barf("sched_state: %d", sched_state);
462 #if defined(THREADED_RTS)
463 // If the run queue is empty, take a spark and turn it into a thread.
465 if (emptyRunQueue(cap)) {
467 spark = findSpark(cap);
470 sched_belch("turning spark of closure %p into a thread",
471 (StgClosure *)spark));
472 createSparkThread(cap,spark);
476 #endif // THREADED_RTS
478 scheduleStartSignalHandlers(cap);
480 // Only check the black holes here if we've nothing else to do.
481 // During normal execution, the black hole list only gets checked
482 // at GC time, to avoid repeatedly traversing this possibly long
483 // list each time around the scheduler.
484 if (emptyRunQueue(cap)) { scheduleCheckBlackHoles(cap); }
486 scheduleCheckWakeupThreads(cap);
488 scheduleCheckBlockedThreads(cap);
490 scheduleDetectDeadlock(cap,task);
491 #if defined(THREADED_RTS)
492 cap = task->cap; // reload cap, it might have changed
495 // Normally, the only way we can get here with no threads to
496 // run is if a keyboard interrupt received during
497 // scheduleCheckBlockedThreads() or scheduleDetectDeadlock().
498 // Additionally, it is not fatal for the
499 // threaded RTS to reach here with no threads to run.
501 // win32: might be here due to awaitEvent() being abandoned
502 // as a result of a console event having been delivered.
503 if ( emptyRunQueue(cap) ) {
504 #if !defined(THREADED_RTS) && !defined(mingw32_HOST_OS)
505 ASSERT(sched_state >= SCHED_INTERRUPTING);
507 continue; // nothing to do
510 #if defined(PARALLEL_HASKELL)
511 scheduleSendPendingMessages();
512 if (emptyRunQueue(cap) && scheduleActivateSpark())
516 ASSERT(next_fish_to_send_at==0); // i.e. no delayed fishes left!
519 /* If we still have no work we need to send a FISH to get a spark
521 if (emptyRunQueue(cap)) {
522 if (!scheduleGetRemoteWork(&receivedFinish)) continue;
523 ASSERT(rtsFalse); // should not happen at the moment
525 // from here: non-empty run queue.
526 // TODO: merge above case with this, only one call processMessages() !
527 if (PacketsWaiting()) { /* process incoming messages, if
528 any pending... only in else
529 because getRemoteWork waits for
531 receivedFinish = processMessages();
536 scheduleProcessEvent(event);
540 // Get a thread to run
542 t = popRunQueue(cap);
544 #if defined(GRAN) || defined(PAR)
545 scheduleGranParReport(); // some kind of debuging output
547 // Sanity check the thread we're about to run. This can be
548 // expensive if there is lots of thread switching going on...
549 IF_DEBUG(sanity,checkTSO(t));
552 #if defined(THREADED_RTS)
553 // Check whether we can run this thread in the current task.
554 // If not, we have to pass our capability to the right task.
556 Task *bound = t->bound;
561 sched_belch("### Running thread %d in bound thread",
563 // yes, the Haskell thread is bound to the current native thread
566 sched_belch("### thread %d bound to another OS thread",
568 // no, bound to a different Haskell thread: pass to that thread
569 pushOnRunQueue(cap,t);
573 // The thread we want to run is unbound.
576 sched_belch("### this OS thread cannot run thread %d", t->id));
577 // no, the current native thread is bound to a different
578 // Haskell thread, so pass it to any worker thread
579 pushOnRunQueue(cap,t);
586 cap->r.rCurrentTSO = t;
588 /* context switches are initiated by the timer signal, unless
589 * the user specified "context switch as often as possible", with
592 if (RtsFlags.ConcFlags.ctxtSwitchTicks == 0
593 && !emptyThreadQueues(cap)) {
599 IF_DEBUG(scheduler, sched_belch("-->> running thread %ld %s ...",
600 (long)t->id, whatNext_strs[t->what_next]));
602 #if defined(PROFILING)
603 startHeapProfTimer();
606 // ----------------------------------------------------------------------
607 // Run the current thread
609 ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
610 ASSERT(t->cap == cap);
612 prev_what_next = t->what_next;
614 errno = t->saved_errno;
615 cap->in_haskell = rtsTrue;
619 recent_activity = ACTIVITY_YES;
621 switch (prev_what_next) {
625 /* Thread already finished, return to scheduler. */
626 ret = ThreadFinished;
632 r = StgRun((StgFunPtr) stg_returnToStackTop, &cap->r);
633 cap = regTableToCapability(r);
638 case ThreadInterpret:
639 cap = interpretBCO(cap);
644 barf("schedule: invalid what_next field");
647 cap->in_haskell = rtsFalse;
649 // The TSO might have moved, eg. if it re-entered the RTS and a GC
650 // happened. So find the new location:
651 t = cap->r.rCurrentTSO;
653 // We have run some Haskell code: there might be blackhole-blocked
654 // threads to wake up now.
655 // Lock-free test here should be ok, we're just setting a flag.
656 if ( blackhole_queue != END_TSO_QUEUE ) {
657 blackholes_need_checking = rtsTrue;
660 // And save the current errno in this thread.
661 // XXX: possibly bogus for SMP because this thread might already
662 // be running again, see code below.
663 t->saved_errno = errno;
665 #if defined(THREADED_RTS)
666 // If ret is ThreadBlocked, and this Task is bound to the TSO that
667 // blocked, we are in limbo - the TSO is now owned by whatever it
668 // is blocked on, and may in fact already have been woken up,
669 // perhaps even on a different Capability. It may be the case
670 // that task->cap != cap. We better yield this Capability
671 // immediately and return to normaility.
672 if (ret == ThreadBlocked) {
674 sched_belch("--<< thread %d (%s) stopped: blocked\n",
675 t->id, whatNext_strs[t->what_next]));
680 ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
681 ASSERT(t->cap == cap);
683 // ----------------------------------------------------------------------
685 // Costs for the scheduler are assigned to CCS_SYSTEM
686 #if defined(PROFILING)
691 #if defined(THREADED_RTS)
692 IF_DEBUG(scheduler,debugBelch("sched (task %p): ", (void *)(unsigned long)(unsigned int)osThreadId()););
693 #elif !defined(GRAN) && !defined(PARALLEL_HASKELL)
694 IF_DEBUG(scheduler,debugBelch("sched: "););
697 schedulePostRunThread();
699 ready_to_gc = rtsFalse;
703 ready_to_gc = scheduleHandleHeapOverflow(cap,t);
707 scheduleHandleStackOverflow(cap,task,t);
711 if (scheduleHandleYield(cap, t, prev_what_next)) {
712 // shortcut for switching between compiler/interpreter:
718 scheduleHandleThreadBlocked(t);
722 if (scheduleHandleThreadFinished(cap, task, t)) return cap;
723 ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
727 barf("schedule: invalid thread return code %d", (int)ret);
730 if (scheduleDoHeapProfile(ready_to_gc)) { ready_to_gc = rtsFalse; }
732 cap = scheduleDoGC(cap,task,rtsFalse,GetRoots);
734 } /* end of while() */
736 IF_PAR_DEBUG(verbose,
737 debugBelch("== Leaving schedule() after having received Finish\n"));
740 /* ----------------------------------------------------------------------------
741 * Setting up the scheduler loop
742 * ------------------------------------------------------------------------- */
745 schedulePreLoop(void)
748 /* set up first event to get things going */
749 /* ToDo: assign costs for system setup and init MainTSO ! */
750 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
752 CurrentTSO, (StgClosure*)NULL, (rtsSpark*)NULL);
755 debugBelch("GRAN: Init CurrentTSO (in schedule) = %p\n",
757 G_TSO(CurrentTSO, 5));
759 if (RtsFlags.GranFlags.Light) {
760 /* Save current time; GranSim Light only */
761 CurrentTSO->gran.clock = CurrentTime[CurrentProc];
766 /* -----------------------------------------------------------------------------
769 * Push work to other Capabilities if we have some.
770 * -------------------------------------------------------------------------- */
772 #if defined(THREADED_RTS)
774 schedulePushWork(Capability *cap USED_IF_THREADS,
775 Task *task USED_IF_THREADS)
777 Capability *free_caps[n_capabilities], *cap0;
780 // migration can be turned off with +RTS -qg
781 if (!RtsFlags.ParFlags.migrate) return;
783 // Check whether we have more threads on our run queue, or sparks
784 // in our pool, that we could hand to another Capability.
785 if ((emptyRunQueue(cap) || cap->run_queue_hd->link == END_TSO_QUEUE)
786 && sparkPoolSizeCap(cap) < 2) {
790 // First grab as many free Capabilities as we can.
791 for (i=0, n_free_caps=0; i < n_capabilities; i++) {
792 cap0 = &capabilities[i];
793 if (cap != cap0 && tryGrabCapability(cap0,task)) {
794 if (!emptyRunQueue(cap0) || cap->returning_tasks_hd != NULL) {
795 // it already has some work, we just grabbed it at
796 // the wrong moment. Or maybe it's deadlocked!
797 releaseCapability(cap0);
799 free_caps[n_free_caps++] = cap0;
804 // we now have n_free_caps free capabilities stashed in
805 // free_caps[]. Share our run queue equally with them. This is
806 // probably the simplest thing we could do; improvements we might
807 // want to do include:
809 // - giving high priority to moving relatively new threads, on
810 // the gournds that they haven't had time to build up a
811 // working set in the cache on this CPU/Capability.
813 // - giving low priority to moving long-lived threads
815 if (n_free_caps > 0) {
816 StgTSO *prev, *t, *next;
817 rtsBool pushed_to_all;
819 IF_DEBUG(scheduler, sched_belch("excess threads on run queue and %d free capabilities, sharing...", n_free_caps));
822 pushed_to_all = rtsFalse;
824 if (cap->run_queue_hd != END_TSO_QUEUE) {
825 prev = cap->run_queue_hd;
827 prev->link = END_TSO_QUEUE;
828 for (; t != END_TSO_QUEUE; t = next) {
830 t->link = END_TSO_QUEUE;
831 if (t->what_next == ThreadRelocated
832 || t->bound == task // don't move my bound thread
833 || tsoLocked(t)) { // don't move a locked thread
836 } else if (i == n_free_caps) {
837 pushed_to_all = rtsTrue;
843 IF_DEBUG(scheduler, sched_belch("pushing thread %d to capability %d", t->id, free_caps[i]->no));
844 appendToRunQueue(free_caps[i],t);
845 if (t->bound) { t->bound->cap = free_caps[i]; }
846 t->cap = free_caps[i];
850 cap->run_queue_tl = prev;
853 // If there are some free capabilities that we didn't push any
854 // threads to, then try to push a spark to each one.
855 if (!pushed_to_all) {
857 // i is the next free capability to push to
858 for (; i < n_free_caps; i++) {
859 if (emptySparkPoolCap(free_caps[i])) {
860 spark = findSpark(cap);
862 IF_DEBUG(scheduler, sched_belch("pushing spark %p to capability %d", spark, free_caps[i]->no));
863 newSpark(&(free_caps[i]->r), spark);
869 // release the capabilities
870 for (i = 0; i < n_free_caps; i++) {
871 task->cap = free_caps[i];
872 releaseCapability(free_caps[i]);
875 task->cap = cap; // reset to point to our Capability.
879 /* ----------------------------------------------------------------------------
880 * Start any pending signal handlers
881 * ------------------------------------------------------------------------- */
883 #if defined(RTS_USER_SIGNALS) && (!defined(THREADED_RTS) || defined(mingw32_HOST_OS))
885 scheduleStartSignalHandlers(Capability *cap)
887 if (signals_pending()) { // safe outside the lock
888 startSignalHandlers(cap);
893 scheduleStartSignalHandlers(Capability *cap STG_UNUSED)
898 /* ----------------------------------------------------------------------------
899 * Check for blocked threads that can be woken up.
900 * ------------------------------------------------------------------------- */
903 scheduleCheckBlockedThreads(Capability *cap USED_IF_NOT_THREADS)
905 #if !defined(THREADED_RTS)
907 // Check whether any waiting threads need to be woken up. If the
908 // run queue is empty, and there are no other tasks running, we
909 // can wait indefinitely for something to happen.
911 if ( !emptyQueue(blocked_queue_hd) || !emptyQueue(sleeping_queue) )
913 awaitEvent( emptyRunQueue(cap) && !blackholes_need_checking );
919 /* ----------------------------------------------------------------------------
920 * Check for threads woken up by other Capabilities
921 * ------------------------------------------------------------------------- */
924 scheduleCheckWakeupThreads(Capability *cap USED_IF_THREADS)
926 #if defined(THREADED_RTS)
927 // Any threads that were woken up by other Capabilities get
928 // appended to our run queue.
929 if (!emptyWakeupQueue(cap)) {
930 ACQUIRE_LOCK(&cap->lock);
931 if (emptyRunQueue(cap)) {
932 cap->run_queue_hd = cap->wakeup_queue_hd;
933 cap->run_queue_tl = cap->wakeup_queue_tl;
935 cap->run_queue_tl->link = cap->wakeup_queue_hd;
936 cap->run_queue_tl = cap->wakeup_queue_tl;
938 cap->wakeup_queue_hd = cap->wakeup_queue_tl = END_TSO_QUEUE;
939 RELEASE_LOCK(&cap->lock);
944 /* ----------------------------------------------------------------------------
945 * Check for threads blocked on BLACKHOLEs that can be woken up
946 * ------------------------------------------------------------------------- */
948 scheduleCheckBlackHoles (Capability *cap)
950 if ( blackholes_need_checking ) // check without the lock first
952 ACQUIRE_LOCK(&sched_mutex);
953 if ( blackholes_need_checking ) {
954 checkBlackHoles(cap);
955 blackholes_need_checking = rtsFalse;
957 RELEASE_LOCK(&sched_mutex);
961 /* ----------------------------------------------------------------------------
962 * Detect deadlock conditions and attempt to resolve them.
963 * ------------------------------------------------------------------------- */
966 scheduleDetectDeadlock (Capability *cap, Task *task)
969 #if defined(PARALLEL_HASKELL)
970 // ToDo: add deadlock detection in GUM (similar to THREADED_RTS) -- HWL
975 * Detect deadlock: when we have no threads to run, there are no
976 * threads blocked, waiting for I/O, or sleeping, and all the
977 * other tasks are waiting for work, we must have a deadlock of
980 if ( emptyThreadQueues(cap) )
982 #if defined(THREADED_RTS)
984 * In the threaded RTS, we only check for deadlock if there
985 * has been no activity in a complete timeslice. This means
986 * we won't eagerly start a full GC just because we don't have
987 * any threads to run currently.
989 if (recent_activity != ACTIVITY_INACTIVE) return;
992 IF_DEBUG(scheduler, sched_belch("deadlocked, forcing major GC..."));
994 // Garbage collection can release some new threads due to
995 // either (a) finalizers or (b) threads resurrected because
996 // they are unreachable and will therefore be sent an
997 // exception. Any threads thus released will be immediately
999 cap = scheduleDoGC (cap, task, rtsTrue/*force major GC*/, GetRoots);
1001 recent_activity = ACTIVITY_DONE_GC;
1003 if ( !emptyRunQueue(cap) ) return;
1005 #if defined(RTS_USER_SIGNALS) && (!defined(THREADED_RTS) || defined(mingw32_HOST_OS))
1006 /* If we have user-installed signal handlers, then wait
1007 * for signals to arrive rather then bombing out with a
1010 if ( anyUserHandlers() ) {
1012 sched_belch("still deadlocked, waiting for signals..."));
1016 if (signals_pending()) {
1017 startSignalHandlers(cap);
1020 // either we have threads to run, or we were interrupted:
1021 ASSERT(!emptyRunQueue(cap) || sched_state >= SCHED_INTERRUPTING);
1025 #if !defined(THREADED_RTS)
1026 /* Probably a real deadlock. Send the current main thread the
1027 * Deadlock exception.
1030 switch (task->tso->why_blocked) {
1032 case BlockedOnBlackHole:
1033 case BlockedOnException:
1035 raiseAsync(cap, task->tso, (StgClosure *)NonTermination_closure);
1038 barf("deadlock: main thread blocked in a strange way");
1046 /* ----------------------------------------------------------------------------
1047 * Process an event (GRAN only)
1048 * ------------------------------------------------------------------------- */
1052 scheduleProcessEvent(rtsEvent *event)
1056 if (RtsFlags.GranFlags.Light)
1057 GranSimLight_enter_system(event, &ActiveTSO); // adjust ActiveTSO etc
1059 /* adjust time based on time-stamp */
1060 if (event->time > CurrentTime[CurrentProc] &&
1061 event->evttype != ContinueThread)
1062 CurrentTime[CurrentProc] = event->time;
1064 /* Deal with the idle PEs (may issue FindWork or MoveSpark events) */
1065 if (!RtsFlags.GranFlags.Light)
1068 IF_DEBUG(gran, debugBelch("GRAN: switch by event-type\n"));
1070 /* main event dispatcher in GranSim */
1071 switch (event->evttype) {
1072 /* Should just be continuing execution */
1073 case ContinueThread:
1074 IF_DEBUG(gran, debugBelch("GRAN: doing ContinueThread\n"));
1075 /* ToDo: check assertion
1076 ASSERT(run_queue_hd != (StgTSO*)NULL &&
1077 run_queue_hd != END_TSO_QUEUE);
1079 /* Ignore ContinueThreads for fetching threads (if synchr comm) */
1080 if (!RtsFlags.GranFlags.DoAsyncFetch &&
1081 procStatus[CurrentProc]==Fetching) {
1082 debugBelch("ghuH: Spurious ContinueThread while Fetching ignored; TSO %d (%p) [PE %d]\n",
1083 CurrentTSO->id, CurrentTSO, CurrentProc);
1086 /* Ignore ContinueThreads for completed threads */
1087 if (CurrentTSO->what_next == ThreadComplete) {
1088 debugBelch("ghuH: found a ContinueThread event for completed thread %d (%p) [PE %d] (ignoring ContinueThread)\n",
1089 CurrentTSO->id, CurrentTSO, CurrentProc);
1092 /* Ignore ContinueThreads for threads that are being migrated */
1093 if (PROCS(CurrentTSO)==Nowhere) {
1094 debugBelch("ghuH: trying to run the migrating TSO %d (%p) [PE %d] (ignoring ContinueThread)\n",
1095 CurrentTSO->id, CurrentTSO, CurrentProc);
1098 /* The thread should be at the beginning of the run queue */
1099 if (CurrentTSO!=run_queue_hds[CurrentProc]) {
1100 debugBelch("ghuH: TSO %d (%p) [PE %d] is not at the start of the run_queue when doing a ContinueThread\n",
1101 CurrentTSO->id, CurrentTSO, CurrentProc);
1102 break; // run the thread anyway
1105 new_event(proc, proc, CurrentTime[proc],
1107 (StgTSO*)NULL, (StgClosure*)NULL, (rtsSpark*)NULL);
1109 */ /* Catches superfluous CONTINUEs -- should be unnecessary */
1110 break; // now actually run the thread; DaH Qu'vam yImuHbej
1113 do_the_fetchnode(event);
1114 goto next_thread; /* handle next event in event queue */
1117 do_the_globalblock(event);
1118 goto next_thread; /* handle next event in event queue */
1121 do_the_fetchreply(event);
1122 goto next_thread; /* handle next event in event queue */
1124 case UnblockThread: /* Move from the blocked queue to the tail of */
1125 do_the_unblock(event);
1126 goto next_thread; /* handle next event in event queue */
1128 case ResumeThread: /* Move from the blocked queue to the tail of */
1129 /* the runnable queue ( i.e. Qu' SImqa'lu') */
1130 event->tso->gran.blocktime +=
1131 CurrentTime[CurrentProc] - event->tso->gran.blockedat;
1132 do_the_startthread(event);
1133 goto next_thread; /* handle next event in event queue */
1136 do_the_startthread(event);
1137 goto next_thread; /* handle next event in event queue */
1140 do_the_movethread(event);
1141 goto next_thread; /* handle next event in event queue */
1144 do_the_movespark(event);
1145 goto next_thread; /* handle next event in event queue */
1148 do_the_findwork(event);
1149 goto next_thread; /* handle next event in event queue */
1152 barf("Illegal event type %u\n", event->evttype);
1155 /* This point was scheduler_loop in the old RTS */
1157 IF_DEBUG(gran, debugBelch("GRAN: after main switch\n"));
1159 TimeOfLastEvent = CurrentTime[CurrentProc];
1160 TimeOfNextEvent = get_time_of_next_event();
1161 IgnoreEvents=(TimeOfNextEvent==0); // HWL HACK
1162 // CurrentTSO = ThreadQueueHd;
1164 IF_DEBUG(gran, debugBelch("GRAN: time of next event is: %ld\n",
1167 if (RtsFlags.GranFlags.Light)
1168 GranSimLight_leave_system(event, &ActiveTSO);
1170 EndOfTimeSlice = CurrentTime[CurrentProc]+RtsFlags.GranFlags.time_slice;
1173 debugBelch("GRAN: end of time-slice is %#lx\n", EndOfTimeSlice));
1175 /* in a GranSim setup the TSO stays on the run queue */
1177 /* Take a thread from the run queue. */
1178 POP_RUN_QUEUE(t); // take_off_run_queue(t);
1181 debugBelch("GRAN: About to run current thread, which is\n");
1184 context_switch = 0; // turned on via GranYield, checking events and time slice
1187 DumpGranEvent(GR_SCHEDULE, t));
1189 procStatus[CurrentProc] = Busy;
1193 /* ----------------------------------------------------------------------------
1194 * Send pending messages (PARALLEL_HASKELL only)
1195 * ------------------------------------------------------------------------- */
1197 #if defined(PARALLEL_HASKELL)
1199 scheduleSendPendingMessages(void)
1205 # if defined(PAR) // global Mem.Mgmt., omit for now
1206 if (PendingFetches != END_BF_QUEUE) {
1211 if (RtsFlags.ParFlags.BufferTime) {
1212 // if we use message buffering, we must send away all message
1213 // packets which have become too old...
1219 /* ----------------------------------------------------------------------------
1220 * Activate spark threads (PARALLEL_HASKELL only)
1221 * ------------------------------------------------------------------------- */
1223 #if defined(PARALLEL_HASKELL)
1225 scheduleActivateSpark(void)
1228 ASSERT(emptyRunQueue());
1229 /* We get here if the run queue is empty and want some work.
1230 We try to turn a spark into a thread, and add it to the run queue,
1231 from where it will be picked up in the next iteration of the scheduler
1235 /* :-[ no local threads => look out for local sparks */
1236 /* the spark pool for the current PE */
1237 pool = &(cap.r.rSparks); // JB: cap = (old) MainCap
1238 if (advisory_thread_count < RtsFlags.ParFlags.maxThreads &&
1239 pool->hd < pool->tl) {
1241 * ToDo: add GC code check that we really have enough heap afterwards!!
1243 * If we're here (no runnable threads) and we have pending
1244 * sparks, we must have a space problem. Get enough space
1245 * to turn one of those pending sparks into a
1249 spark = findSpark(rtsFalse); /* get a spark */
1250 if (spark != (rtsSpark) NULL) {
1251 tso = createThreadFromSpark(spark); /* turn the spark into a thread */
1252 IF_PAR_DEBUG(fish, // schedule,
1253 debugBelch("==== schedule: Created TSO %d (%p); %d threads active\n",
1254 tso->id, tso, advisory_thread_count));
1256 if (tso==END_TSO_QUEUE) { /* failed to activate spark->back to loop */
1257 IF_PAR_DEBUG(fish, // schedule,
1258 debugBelch("==^^ failed to create thread from spark @ %lx\n",
1260 return rtsFalse; /* failed to generate a thread */
1261 } /* otherwise fall through & pick-up new tso */
1263 IF_PAR_DEBUG(fish, // schedule,
1264 debugBelch("==^^ no local sparks (spark pool contains only NFs: %d)\n",
1265 spark_queue_len(pool)));
1266 return rtsFalse; /* failed to generate a thread */
1268 return rtsTrue; /* success in generating a thread */
1269 } else { /* no more threads permitted or pool empty */
1270 return rtsFalse; /* failed to generateThread */
1273 tso = NULL; // avoid compiler warning only
1274 return rtsFalse; /* dummy in non-PAR setup */
1277 #endif // PARALLEL_HASKELL
1279 /* ----------------------------------------------------------------------------
1280 * Get work from a remote node (PARALLEL_HASKELL only)
1281 * ------------------------------------------------------------------------- */
1283 #if defined(PARALLEL_HASKELL)
1285 scheduleGetRemoteWork(rtsBool *receivedFinish)
1287 ASSERT(emptyRunQueue());
1289 if (RtsFlags.ParFlags.BufferTime) {
1290 IF_PAR_DEBUG(verbose,
1291 debugBelch("...send all pending data,"));
1294 for (i=1; i<=nPEs; i++)
1295 sendImmediately(i); // send all messages away immediately
1299 //++EDEN++ idle() , i.e. send all buffers, wait for work
1300 // suppress fishing in EDEN... just look for incoming messages
1301 // (blocking receive)
1302 IF_PAR_DEBUG(verbose,
1303 debugBelch("...wait for incoming messages...\n"));
1304 *receivedFinish = processMessages(); // blocking receive...
1306 // and reenter scheduling loop after having received something
1307 // (return rtsFalse below)
1309 # else /* activate SPARKS machinery */
1310 /* We get here, if we have no work, tried to activate a local spark, but still
1311 have no work. We try to get a remote spark, by sending a FISH message.
1312 Thread migration should be added here, and triggered when a sequence of
1313 fishes returns without work. */
1314 delay = (RtsFlags.ParFlags.fishDelay!=0ll ? RtsFlags.ParFlags.fishDelay : 0ll);
1316 /* =8-[ no local sparks => look for work on other PEs */
1318 * We really have absolutely no work. Send out a fish
1319 * (there may be some out there already), and wait for
1320 * something to arrive. We clearly can't run any threads
1321 * until a SCHEDULE or RESUME arrives, and so that's what
1322 * we're hoping to see. (Of course, we still have to
1323 * respond to other types of messages.)
1325 rtsTime now = msTime() /*CURRENT_TIME*/;
1326 IF_PAR_DEBUG(verbose,
1327 debugBelch("-- now=%ld\n", now));
1328 IF_PAR_DEBUG(fish, // verbose,
1329 if (outstandingFishes < RtsFlags.ParFlags.maxFishes &&
1330 (last_fish_arrived_at!=0 &&
1331 last_fish_arrived_at+delay > now)) {
1332 debugBelch("--$$ <%llu> delaying FISH until %llu (last fish %llu, delay %llu)\n",
1333 now, last_fish_arrived_at+delay,
1334 last_fish_arrived_at,
1338 if (outstandingFishes < RtsFlags.ParFlags.maxFishes &&
1339 advisory_thread_count < RtsFlags.ParFlags.maxThreads) { // send a FISH, but when?
1340 if (last_fish_arrived_at==0 ||
1341 (last_fish_arrived_at+delay <= now)) { // send FISH now!
1342 /* outstandingFishes is set in sendFish, processFish;
1343 avoid flooding system with fishes via delay */
1344 next_fish_to_send_at = 0;
1346 /* ToDo: this should be done in the main scheduling loop to avoid the
1347 busy wait here; not so bad if fish delay is very small */
1348 int iq = 0; // DEBUGGING -- HWL
1349 next_fish_to_send_at = last_fish_arrived_at+delay; // remember when to send
1350 /* send a fish when ready, but process messages that arrive in the meantime */
1352 if (PacketsWaiting()) {
1354 *receivedFinish = processMessages();
1357 } while (!*receivedFinish || now<next_fish_to_send_at);
1358 // JB: This means the fish could become obsolete, if we receive
1359 // work. Better check for work again?
1360 // last line: while (!receivedFinish || !haveWork || now<...)
1361 // next line: if (receivedFinish || haveWork )
1363 if (*receivedFinish) // no need to send a FISH if we are finishing anyway
1364 return rtsFalse; // NB: this will leave scheduler loop
1365 // immediately after return!
1367 IF_PAR_DEBUG(fish, // verbose,
1368 debugBelch("--$$ <%llu> sent delayed fish (%d processMessages); active/total threads=%d/%d\n",now,iq,run_queue_len(),advisory_thread_count));
1372 // JB: IMHO, this should all be hidden inside sendFish(...)
1374 sendFish(pe, thisPE, NEW_FISH_AGE, NEW_FISH_HISTORY,
1377 // Global statistics: count no. of fishes
1378 if (RtsFlags.ParFlags.ParStats.Global &&
1379 RtsFlags.GcFlags.giveStats > NO_GC_STATS) {
1380 globalParStats.tot_fish_mess++;
1384 /* delayed fishes must have been sent by now! */
1385 next_fish_to_send_at = 0;
1388 *receivedFinish = processMessages();
1389 # endif /* SPARKS */
1392 /* NB: this function always returns rtsFalse, meaning the scheduler
1393 loop continues with the next iteration;
1395 return code means success in finding work; we enter this function
1396 if there is no local work, thus have to send a fish which takes
1397 time until it arrives with work; in the meantime we should process
1398 messages in the main loop;
1401 #endif // PARALLEL_HASKELL
1403 /* ----------------------------------------------------------------------------
1404 * PAR/GRAN: Report stats & debugging info(?)
1405 * ------------------------------------------------------------------------- */
1407 #if defined(PAR) || defined(GRAN)
1409 scheduleGranParReport(void)
1411 ASSERT(run_queue_hd != END_TSO_QUEUE);
1413 /* Take a thread from the run queue, if we have work */
1414 POP_RUN_QUEUE(t); // take_off_run_queue(END_TSO_QUEUE);
1416 /* If this TSO has got its outport closed in the meantime,
1417 * it mustn't be run. Instead, we have to clean it up as if it was finished.
1418 * It has to be marked as TH_DEAD for this purpose.
1419 * If it is TH_TERM instead, it is supposed to have finished in the normal way.
1421 JB: TODO: investigate wether state change field could be nuked
1422 entirely and replaced by the normal tso state (whatnext
1423 field). All we want to do is to kill tsos from outside.
1426 /* ToDo: write something to the log-file
1427 if (RTSflags.ParFlags.granSimStats && !sameThread)
1428 DumpGranEvent(GR_SCHEDULE, RunnableThreadsHd);
1432 /* the spark pool for the current PE */
1433 pool = &(cap.r.rSparks); // cap = (old) MainCap
1436 debugBelch("--=^ %d threads, %d sparks on [%#x]\n",
1437 run_queue_len(), spark_queue_len(pool), CURRENT_PROC));
1440 debugBelch("--=^ %d threads, %d sparks on [%#x]\n",
1441 run_queue_len(), spark_queue_len(pool), CURRENT_PROC));
1443 if (RtsFlags.ParFlags.ParStats.Full &&
1444 (t->par.sparkname != (StgInt)0) && // only log spark generated threads
1445 (emitSchedule || // forced emit
1446 (t && LastTSO && t->id != LastTSO->id))) {
1448 we are running a different TSO, so write a schedule event to log file
1449 NB: If we use fair scheduling we also have to write a deschedule
1450 event for LastTSO; with unfair scheduling we know that the
1451 previous tso has blocked whenever we switch to another tso, so
1452 we don't need it in GUM for now
1454 IF_PAR_DEBUG(fish, // schedule,
1455 debugBelch("____ scheduling spark generated thread %d (%lx) (%lx) via a forced emit\n",t->id,t,t->par.sparkname));
1457 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
1458 GR_SCHEDULE, t, (StgClosure *)NULL, 0, 0);
1459 emitSchedule = rtsFalse;
1464 /* ----------------------------------------------------------------------------
1465 * After running a thread...
1466 * ------------------------------------------------------------------------- */
1469 schedulePostRunThread(void)
1472 /* HACK 675: if the last thread didn't yield, make sure to print a
1473 SCHEDULE event to the log file when StgRunning the next thread, even
1474 if it is the same one as before */
1476 TimeOfLastYield = CURRENT_TIME;
1479 /* some statistics gathering in the parallel case */
1481 #if defined(GRAN) || defined(PAR) || defined(EDEN)
1485 IF_DEBUG(gran, DumpGranEvent(GR_DESCHEDULE, t));
1486 globalGranStats.tot_heapover++;
1488 globalParStats.tot_heapover++;
1495 DumpGranEvent(GR_DESCHEDULE, t));
1496 globalGranStats.tot_stackover++;
1499 // DumpGranEvent(GR_DESCHEDULE, t);
1500 globalParStats.tot_stackover++;
1504 case ThreadYielding:
1507 DumpGranEvent(GR_DESCHEDULE, t));
1508 globalGranStats.tot_yields++;
1511 // DumpGranEvent(GR_DESCHEDULE, t);
1512 globalParStats.tot_yields++;
1519 debugBelch("--<< thread %ld (%p; %s) stopped, blocking on node %p [PE %d] with BQ: ",
1520 t->id, t, whatNext_strs[t->what_next], t->block_info.closure,
1521 (t->block_info.closure==(StgClosure*)NULL ? 99 : where_is(t->block_info.closure)));
1522 if (t->block_info.closure!=(StgClosure*)NULL)
1523 print_bq(t->block_info.closure);
1526 // ??? needed; should emit block before
1528 DumpGranEvent(GR_DESCHEDULE, t));
1529 prune_eventq(t, (StgClosure *)NULL); // prune ContinueThreads for t
1532 ASSERT(procStatus[CurrentProc]==Busy ||
1533 ((procStatus[CurrentProc]==Fetching) &&
1534 (t->block_info.closure!=(StgClosure*)NULL)));
1535 if (run_queue_hds[CurrentProc] == END_TSO_QUEUE &&
1536 !(!RtsFlags.GranFlags.DoAsyncFetch &&
1537 procStatus[CurrentProc]==Fetching))
1538 procStatus[CurrentProc] = Idle;
1541 //++PAR++ blockThread() writes the event (change?)
1545 case ThreadFinished:
1549 barf("parGlobalStats: unknown return code");
1555 /* -----------------------------------------------------------------------------
1556 * Handle a thread that returned to the scheduler with ThreadHeepOverflow
1557 * -------------------------------------------------------------------------- */
1560 scheduleHandleHeapOverflow( Capability *cap, StgTSO *t )
1562 // did the task ask for a large block?
1563 if (cap->r.rHpAlloc > BLOCK_SIZE) {
1564 // if so, get one and push it on the front of the nursery.
1568 blocks = (lnat)BLOCK_ROUND_UP(cap->r.rHpAlloc) / BLOCK_SIZE;
1571 debugBelch("--<< thread %ld (%s) stopped: requesting a large block (size %ld)\n",
1572 (long)t->id, whatNext_strs[t->what_next], blocks));
1574 // don't do this if the nursery is (nearly) full, we'll GC first.
1575 if (cap->r.rCurrentNursery->link != NULL ||
1576 cap->r.rNursery->n_blocks == 1) { // paranoia to prevent infinite loop
1577 // if the nursery has only one block.
1580 bd = allocGroup( blocks );
1582 cap->r.rNursery->n_blocks += blocks;
1584 // link the new group into the list
1585 bd->link = cap->r.rCurrentNursery;
1586 bd->u.back = cap->r.rCurrentNursery->u.back;
1587 if (cap->r.rCurrentNursery->u.back != NULL) {
1588 cap->r.rCurrentNursery->u.back->link = bd;
1590 #if !defined(THREADED_RTS)
1591 ASSERT(g0s0->blocks == cap->r.rCurrentNursery &&
1592 g0s0 == cap->r.rNursery);
1594 cap->r.rNursery->blocks = bd;
1596 cap->r.rCurrentNursery->u.back = bd;
1598 // initialise it as a nursery block. We initialise the
1599 // step, gen_no, and flags field of *every* sub-block in
1600 // this large block, because this is easier than making
1601 // sure that we always find the block head of a large
1602 // block whenever we call Bdescr() (eg. evacuate() and
1603 // isAlive() in the GC would both have to do this, at
1607 for (x = bd; x < bd + blocks; x++) {
1608 x->step = cap->r.rNursery;
1614 // This assert can be a killer if the app is doing lots
1615 // of large block allocations.
1616 IF_DEBUG(sanity, checkNurserySanity(cap->r.rNursery));
1618 // now update the nursery to point to the new block
1619 cap->r.rCurrentNursery = bd;
1621 // we might be unlucky and have another thread get on the
1622 // run queue before us and steal the large block, but in that
1623 // case the thread will just end up requesting another large
1625 pushOnRunQueue(cap,t);
1626 return rtsFalse; /* not actually GC'ing */
1631 debugBelch("--<< thread %ld (%s) stopped: HeapOverflow\n",
1632 (long)t->id, whatNext_strs[t->what_next]));
1634 ASSERT(!is_on_queue(t,CurrentProc));
1635 #elif defined(PARALLEL_HASKELL)
1636 /* Currently we emit a DESCHEDULE event before GC in GUM.
1637 ToDo: either add separate event to distinguish SYSTEM time from rest
1638 or just nuke this DESCHEDULE (and the following SCHEDULE) */
1639 if (0 && RtsFlags.ParFlags.ParStats.Full) {
1640 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
1641 GR_DESCHEDULE, t, (StgClosure *)NULL, 0, 0);
1642 emitSchedule = rtsTrue;
1646 pushOnRunQueue(cap,t);
1648 /* actual GC is done at the end of the while loop in schedule() */
1651 /* -----------------------------------------------------------------------------
1652 * Handle a thread that returned to the scheduler with ThreadStackOverflow
1653 * -------------------------------------------------------------------------- */
1656 scheduleHandleStackOverflow (Capability *cap, Task *task, StgTSO *t)
1658 IF_DEBUG(scheduler,debugBelch("--<< thread %ld (%s) stopped, StackOverflow\n",
1659 (long)t->id, whatNext_strs[t->what_next]));
1660 /* just adjust the stack for this thread, then pop it back
1664 /* enlarge the stack */
1665 StgTSO *new_t = threadStackOverflow(cap, t);
1667 /* The TSO attached to this Task may have moved, so update the
1670 if (task->tso == t) {
1673 pushOnRunQueue(cap,new_t);
1677 /* -----------------------------------------------------------------------------
1678 * Handle a thread that returned to the scheduler with ThreadYielding
1679 * -------------------------------------------------------------------------- */
1682 scheduleHandleYield( Capability *cap, StgTSO *t, nat prev_what_next )
1684 // Reset the context switch flag. We don't do this just before
1685 // running the thread, because that would mean we would lose ticks
1686 // during GC, which can lead to unfair scheduling (a thread hogs
1687 // the CPU because the tick always arrives during GC). This way
1688 // penalises threads that do a lot of allocation, but that seems
1689 // better than the alternative.
1692 /* put the thread back on the run queue. Then, if we're ready to
1693 * GC, check whether this is the last task to stop. If so, wake
1694 * up the GC thread. getThread will block during a GC until the
1698 if (t->what_next != prev_what_next) {
1699 debugBelch("--<< thread %ld (%s) stopped to switch evaluators\n",
1700 (long)t->id, whatNext_strs[t->what_next]);
1702 debugBelch("--<< thread %ld (%s) stopped, yielding\n",
1703 (long)t->id, whatNext_strs[t->what_next]);
1708 //debugBelch("&& Doing sanity check on yielding TSO %ld.", t->id);
1710 ASSERT(t->link == END_TSO_QUEUE);
1712 // Shortcut if we're just switching evaluators: don't bother
1713 // doing stack squeezing (which can be expensive), just run the
1715 if (t->what_next != prev_what_next) {
1720 ASSERT(!is_on_queue(t,CurrentProc));
1723 //debugBelch("&& Doing sanity check on all ThreadQueues (and their TSOs).");
1724 checkThreadQsSanity(rtsTrue));
1728 addToRunQueue(cap,t);
1731 /* add a ContinueThread event to actually process the thread */
1732 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
1734 t, (StgClosure*)NULL, (rtsSpark*)NULL);
1736 debugBelch("GRAN: eventq and runnableq after adding yielded thread to queue again:\n");
1743 /* -----------------------------------------------------------------------------
1744 * Handle a thread that returned to the scheduler with ThreadBlocked
1745 * -------------------------------------------------------------------------- */
1748 scheduleHandleThreadBlocked( StgTSO *t
1749 #if !defined(GRAN) && !defined(DEBUG)
1756 debugBelch("--<< thread %ld (%p; %s) stopped, blocking on node %p [PE %d] with BQ: \n",
1757 t->id, t, whatNext_strs[t->what_next], t->block_info.closure, (t->block_info.closure==(StgClosure*)NULL ? 99 : where_is(t->block_info.closure)));
1758 if (t->block_info.closure!=(StgClosure*)NULL) print_bq(t->block_info.closure));
1760 // ??? needed; should emit block before
1762 DumpGranEvent(GR_DESCHEDULE, t));
1763 prune_eventq(t, (StgClosure *)NULL); // prune ContinueThreads for t
1766 ASSERT(procStatus[CurrentProc]==Busy ||
1767 ((procStatus[CurrentProc]==Fetching) &&
1768 (t->block_info.closure!=(StgClosure*)NULL)));
1769 if (run_queue_hds[CurrentProc] == END_TSO_QUEUE &&
1770 !(!RtsFlags.GranFlags.DoAsyncFetch &&
1771 procStatus[CurrentProc]==Fetching))
1772 procStatus[CurrentProc] = Idle;
1776 debugBelch("--<< thread %ld (%p; %s) stopped, blocking on node %p with BQ: \n",
1777 t->id, t, whatNext_strs[t->what_next], t->block_info.closure));
1780 if (t->block_info.closure!=(StgClosure*)NULL)
1781 print_bq(t->block_info.closure));
1783 /* Send a fetch (if BlockedOnGA) and dump event to log file */
1786 /* whatever we schedule next, we must log that schedule */
1787 emitSchedule = rtsTrue;
1791 // We don't need to do anything. The thread is blocked, and it
1792 // has tidied up its stack and placed itself on whatever queue
1793 // it needs to be on.
1795 #if !defined(THREADED_RTS)
1796 ASSERT(t->why_blocked != NotBlocked);
1797 // This might not be true under THREADED_RTS: we don't have
1798 // exclusive access to this TSO, so someone might have
1799 // woken it up by now. This actually happens: try
1800 // conc023 +RTS -N2.
1804 debugBelch("--<< thread %d (%s) stopped: ",
1805 t->id, whatNext_strs[t->what_next]);
1806 printThreadBlockage(t);
1809 /* Only for dumping event to log file
1810 ToDo: do I need this in GranSim, too?
1816 /* -----------------------------------------------------------------------------
1817 * Handle a thread that returned to the scheduler with ThreadFinished
1818 * -------------------------------------------------------------------------- */
1821 scheduleHandleThreadFinished (Capability *cap STG_UNUSED, Task *task, StgTSO *t)
1823 /* Need to check whether this was a main thread, and if so,
1824 * return with the return value.
1826 * We also end up here if the thread kills itself with an
1827 * uncaught exception, see Exception.cmm.
1829 IF_DEBUG(scheduler,debugBelch("--++ thread %d (%s) finished\n",
1830 t->id, whatNext_strs[t->what_next]));
1833 endThread(t, CurrentProc); // clean-up the thread
1834 #elif defined(PARALLEL_HASKELL)
1835 /* For now all are advisory -- HWL */
1836 //if(t->priority==AdvisoryPriority) ??
1837 advisory_thread_count--; // JB: Caution with this counter, buggy!
1840 if(t->dist.priority==RevalPriority)
1844 # if defined(EDENOLD)
1845 // the thread could still have an outport... (BUG)
1846 if (t->eden.outport != -1) {
1847 // delete the outport for the tso which has finished...
1848 IF_PAR_DEBUG(eden_ports,
1849 debugBelch("WARNING: Scheduler removes outport %d for TSO %d.\n",
1850 t->eden.outport, t->id));
1853 // thread still in the process (HEAVY BUG! since outport has just been closed...)
1854 if (t->eden.epid != -1) {
1855 IF_PAR_DEBUG(eden_ports,
1856 debugBelch("WARNING: Scheduler removes TSO %d from process %d .\n",
1857 t->id, t->eden.epid));
1858 removeTSOfromProcess(t);
1863 if (RtsFlags.ParFlags.ParStats.Full &&
1864 !RtsFlags.ParFlags.ParStats.Suppressed)
1865 DumpEndEvent(CURRENT_PROC, t, rtsFalse /* not mandatory */);
1867 // t->par only contains statistics: left out for now...
1869 debugBelch("**** end thread: ended sparked thread %d (%lx); sparkname: %lx\n",
1870 t->id,t,t->par.sparkname));
1872 #endif // PARALLEL_HASKELL
1875 // Check whether the thread that just completed was a bound
1876 // thread, and if so return with the result.
1878 // There is an assumption here that all thread completion goes
1879 // through this point; we need to make sure that if a thread
1880 // ends up in the ThreadKilled state, that it stays on the run
1881 // queue so it can be dealt with here.
1886 if (t->bound != task) {
1887 #if !defined(THREADED_RTS)
1888 // Must be a bound thread that is not the topmost one. Leave
1889 // it on the run queue until the stack has unwound to the
1890 // point where we can deal with this. Leaving it on the run
1891 // queue also ensures that the garbage collector knows about
1892 // this thread and its return value (it gets dropped from the
1893 // all_threads list so there's no other way to find it).
1894 appendToRunQueue(cap,t);
1897 // this cannot happen in the threaded RTS, because a
1898 // bound thread can only be run by the appropriate Task.
1899 barf("finished bound thread that isn't mine");
1903 ASSERT(task->tso == t);
1905 if (t->what_next == ThreadComplete) {
1907 // NOTE: return val is tso->sp[1] (see StgStartup.hc)
1908 *(task->ret) = (StgClosure *)task->tso->sp[1];
1910 task->stat = Success;
1913 *(task->ret) = NULL;
1915 if (sched_state >= SCHED_INTERRUPTING) {
1916 task->stat = Interrupted;
1918 task->stat = Killed;
1922 removeThreadLabel((StgWord)task->tso->id);
1924 return rtsTrue; // tells schedule() to return
1930 /* -----------------------------------------------------------------------------
1931 * Perform a heap census, if PROFILING
1932 * -------------------------------------------------------------------------- */
1935 scheduleDoHeapProfile( rtsBool ready_to_gc STG_UNUSED )
1937 #if defined(PROFILING)
1938 // When we have +RTS -i0 and we're heap profiling, do a census at
1939 // every GC. This lets us get repeatable runs for debugging.
1940 if (performHeapProfile ||
1941 (RtsFlags.ProfFlags.profileInterval==0 &&
1942 RtsFlags.ProfFlags.doHeapProfile && ready_to_gc)) {
1944 // checking black holes is necessary before GC, otherwise
1945 // there may be threads that are unreachable except by the
1946 // blackhole queue, which the GC will consider to be
1948 scheduleCheckBlackHoles(&MainCapability);
1950 IF_DEBUG(scheduler, sched_belch("garbage collecting before heap census"));
1951 GarbageCollect(GetRoots, rtsTrue);
1953 IF_DEBUG(scheduler, sched_belch("performing heap census"));
1956 performHeapProfile = rtsFalse;
1957 return rtsTrue; // true <=> we already GC'd
1963 /* -----------------------------------------------------------------------------
1964 * Perform a garbage collection if necessary
1965 * -------------------------------------------------------------------------- */
1968 scheduleDoGC (Capability *cap, Task *task USED_IF_THREADS,
1969 rtsBool force_major, void (*get_roots)(evac_fn))
1973 static volatile StgWord waiting_for_gc;
1974 rtsBool was_waiting;
1979 // In order to GC, there must be no threads running Haskell code.
1980 // Therefore, the GC thread needs to hold *all* the capabilities,
1981 // and release them after the GC has completed.
1983 // This seems to be the simplest way: previous attempts involved
1984 // making all the threads with capabilities give up their
1985 // capabilities and sleep except for the *last* one, which
1986 // actually did the GC. But it's quite hard to arrange for all
1987 // the other tasks to sleep and stay asleep.
1990 was_waiting = cas(&waiting_for_gc, 0, 1);
1993 IF_DEBUG(scheduler, sched_belch("someone else is trying to GC..."));
1994 if (cap) yieldCapability(&cap,task);
1995 } while (waiting_for_gc);
1996 return cap; // NOTE: task->cap might have changed here
1999 for (i=0; i < n_capabilities; i++) {
2000 IF_DEBUG(scheduler, sched_belch("ready_to_gc, grabbing all the capabilies (%d/%d)", i, n_capabilities));
2001 if (cap != &capabilities[i]) {
2002 Capability *pcap = &capabilities[i];
2003 // we better hope this task doesn't get migrated to
2004 // another Capability while we're waiting for this one.
2005 // It won't, because load balancing happens while we have
2006 // all the Capabilities, but even so it's a slightly
2007 // unsavoury invariant.
2010 waitForReturnCapability(&pcap, task);
2011 if (pcap != &capabilities[i]) {
2012 barf("scheduleDoGC: got the wrong capability");
2017 waiting_for_gc = rtsFalse;
2020 /* Kick any transactions which are invalid back to their
2021 * atomically frames. When next scheduled they will try to
2022 * commit, this commit will fail and they will retry.
2027 for (t = all_threads; t != END_TSO_QUEUE; t = next) {
2028 if (t->what_next == ThreadRelocated) {
2031 next = t->global_link;
2032 if (t -> trec != NO_TREC && t -> why_blocked == NotBlocked) {
2033 if (!stmValidateNestOfTransactions (t -> trec)) {
2034 IF_DEBUG(stm, sched_belch("trec %p found wasting its time", t));
2036 // strip the stack back to the
2037 // ATOMICALLY_FRAME, aborting the (nested)
2038 // transaction, and saving the stack of any
2039 // partially-evaluated thunks on the heap.
2040 raiseAsync_(&capabilities[0], t, NULL, rtsTrue, NULL);
2043 ASSERT(get_itbl((StgClosure *)t->sp)->type == ATOMICALLY_FRAME);
2051 // so this happens periodically:
2052 if (cap) scheduleCheckBlackHoles(cap);
2054 IF_DEBUG(scheduler, printAllThreads());
2057 * We now have all the capabilities; if we're in an interrupting
2058 * state, then we should take the opportunity to delete all the
2059 * threads in the system.
2061 if (sched_state >= SCHED_INTERRUPTING) {
2062 deleteAllThreads(&capabilities[0]);
2063 sched_state = SCHED_INTERRUPTED;
2066 /* everybody back, start the GC.
2067 * Could do it in this thread, or signal a condition var
2068 * to do it in another thread. Either way, we need to
2069 * broadcast on gc_pending_cond afterward.
2071 #if defined(THREADED_RTS)
2072 IF_DEBUG(scheduler,sched_belch("doing GC"));
2074 GarbageCollect(get_roots, force_major);
2076 #if defined(THREADED_RTS)
2077 // release our stash of capabilities.
2078 for (i = 0; i < n_capabilities; i++) {
2079 if (cap != &capabilities[i]) {
2080 task->cap = &capabilities[i];
2081 releaseCapability(&capabilities[i]);
2092 /* add a ContinueThread event to continue execution of current thread */
2093 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
2095 t, (StgClosure*)NULL, (rtsSpark*)NULL);
2097 debugBelch("GRAN: eventq and runnableq after Garbage collection:\n\n");
2105 /* ---------------------------------------------------------------------------
2106 * rtsSupportsBoundThreads(): is the RTS built to support bound threads?
2107 * used by Control.Concurrent for error checking.
2108 * ------------------------------------------------------------------------- */
2111 rtsSupportsBoundThreads(void)
2113 #if defined(THREADED_RTS)
2120 /* ---------------------------------------------------------------------------
2121 * isThreadBound(tso): check whether tso is bound to an OS thread.
2122 * ------------------------------------------------------------------------- */
2125 isThreadBound(StgTSO* tso USED_IF_THREADS)
2127 #if defined(THREADED_RTS)
2128 return (tso->bound != NULL);
2133 /* ---------------------------------------------------------------------------
2134 * Singleton fork(). Do not copy any running threads.
2135 * ------------------------------------------------------------------------- */
2137 #if !defined(mingw32_HOST_OS)
2138 #define FORKPROCESS_PRIMOP_SUPPORTED
2141 #ifdef FORKPROCESS_PRIMOP_SUPPORTED
2143 deleteThread_(Capability *cap, StgTSO *tso);
2146 forkProcess(HsStablePtr *entry
2147 #ifndef FORKPROCESS_PRIMOP_SUPPORTED
2152 #ifdef FORKPROCESS_PRIMOP_SUPPORTED
2158 #if defined(THREADED_RTS)
2159 if (RtsFlags.ParFlags.nNodes > 1) {
2160 errorBelch("forking not supported with +RTS -N<n> greater than 1");
2161 stg_exit(EXIT_FAILURE);
2165 IF_DEBUG(scheduler,sched_belch("forking!"));
2167 // ToDo: for SMP, we should probably acquire *all* the capabilities
2172 if (pid) { // parent
2174 // just return the pid
2180 // Now, all OS threads except the thread that forked are
2181 // stopped. We need to stop all Haskell threads, including
2182 // those involved in foreign calls. Also we need to delete
2183 // all Tasks, because they correspond to OS threads that are
2186 for (t = all_threads; t != END_TSO_QUEUE; t = next) {
2187 if (t->what_next == ThreadRelocated) {
2190 next = t->global_link;
2191 // don't allow threads to catch the ThreadKilled
2192 // exception, but we do want to raiseAsync() because these
2193 // threads may be evaluating thunks that we need later.
2194 deleteThread_(cap,t);
2198 // Empty the run queue. It seems tempting to let all the
2199 // killed threads stay on the run queue as zombies to be
2200 // cleaned up later, but some of them correspond to bound
2201 // threads for which the corresponding Task does not exist.
2202 cap->run_queue_hd = END_TSO_QUEUE;
2203 cap->run_queue_tl = END_TSO_QUEUE;
2205 // Any suspended C-calling Tasks are no more, their OS threads
2207 cap->suspended_ccalling_tasks = NULL;
2209 // Empty the all_threads list. Otherwise, the garbage
2210 // collector may attempt to resurrect some of these threads.
2211 all_threads = END_TSO_QUEUE;
2213 // Wipe the task list, except the current Task.
2214 ACQUIRE_LOCK(&sched_mutex);
2215 for (task = all_tasks; task != NULL; task=task->all_link) {
2216 if (task != cap->running_task) {
2220 RELEASE_LOCK(&sched_mutex);
2222 #if defined(THREADED_RTS)
2223 // Wipe our spare workers list, they no longer exist. New
2224 // workers will be created if necessary.
2225 cap->spare_workers = NULL;
2226 cap->returning_tasks_hd = NULL;
2227 cap->returning_tasks_tl = NULL;
2230 cap = rts_evalStableIO(cap, entry, NULL); // run the action
2231 rts_checkSchedStatus("forkProcess",cap);
2234 hs_exit(); // clean up and exit
2235 stg_exit(EXIT_SUCCESS);
2237 #else /* !FORKPROCESS_PRIMOP_SUPPORTED */
2238 barf("forkProcess#: primop not supported on this platform, sorry!\n");
2243 /* ---------------------------------------------------------------------------
2244 * Delete all the threads in the system
2245 * ------------------------------------------------------------------------- */
2248 deleteAllThreads ( Capability *cap )
2251 IF_DEBUG(scheduler,sched_belch("deleting all threads"));
2252 for (t = all_threads; t != END_TSO_QUEUE; t = next) {
2253 if (t->what_next == ThreadRelocated) {
2256 next = t->global_link;
2257 deleteThread(cap,t);
2261 // The run queue now contains a bunch of ThreadKilled threads. We
2262 // must not throw these away: the main thread(s) will be in there
2263 // somewhere, and the main scheduler loop has to deal with it.
2264 // Also, the run queue is the only thing keeping these threads from
2265 // being GC'd, and we don't want the "main thread has been GC'd" panic.
2267 #if !defined(THREADED_RTS)
2268 ASSERT(blocked_queue_hd == END_TSO_QUEUE);
2269 ASSERT(sleeping_queue == END_TSO_QUEUE);
2273 /* -----------------------------------------------------------------------------
2274 Managing the suspended_ccalling_tasks list.
2275 Locks required: sched_mutex
2276 -------------------------------------------------------------------------- */
2279 suspendTask (Capability *cap, Task *task)
2281 ASSERT(task->next == NULL && task->prev == NULL);
2282 task->next = cap->suspended_ccalling_tasks;
2284 if (cap->suspended_ccalling_tasks) {
2285 cap->suspended_ccalling_tasks->prev = task;
2287 cap->suspended_ccalling_tasks = task;
2291 recoverSuspendedTask (Capability *cap, Task *task)
2294 task->prev->next = task->next;
2296 ASSERT(cap->suspended_ccalling_tasks == task);
2297 cap->suspended_ccalling_tasks = task->next;
2300 task->next->prev = task->prev;
2302 task->next = task->prev = NULL;
2305 /* ---------------------------------------------------------------------------
2306 * Suspending & resuming Haskell threads.
2308 * When making a "safe" call to C (aka _ccall_GC), the task gives back
2309 * its capability before calling the C function. This allows another
2310 * task to pick up the capability and carry on running Haskell
2311 * threads. It also means that if the C call blocks, it won't lock
2314 * The Haskell thread making the C call is put to sleep for the
2315 * duration of the call, on the susepended_ccalling_threads queue. We
2316 * give out a token to the task, which it can use to resume the thread
2317 * on return from the C function.
2318 * ------------------------------------------------------------------------- */
2321 suspendThread (StgRegTable *reg)
2324 int saved_errno = errno;
2328 /* assume that *reg is a pointer to the StgRegTable part of a Capability.
2330 cap = regTableToCapability(reg);
2332 task = cap->running_task;
2333 tso = cap->r.rCurrentTSO;
2336 sched_belch("thread %d did a safe foreign call", cap->r.rCurrentTSO->id));
2338 // XXX this might not be necessary --SDM
2339 tso->what_next = ThreadRunGHC;
2341 threadPaused(cap,tso);
2343 if(tso->blocked_exceptions == NULL) {
2344 tso->why_blocked = BlockedOnCCall;
2345 tso->blocked_exceptions = END_TSO_QUEUE;
2347 tso->why_blocked = BlockedOnCCall_NoUnblockExc;
2350 // Hand back capability
2351 task->suspended_tso = tso;
2353 ACQUIRE_LOCK(&cap->lock);
2355 suspendTask(cap,task);
2356 cap->in_haskell = rtsFalse;
2357 releaseCapability_(cap);
2359 RELEASE_LOCK(&cap->lock);
2361 #if defined(THREADED_RTS)
2362 /* Preparing to leave the RTS, so ensure there's a native thread/task
2363 waiting to take over.
2365 IF_DEBUG(scheduler, sched_belch("thread %d: leaving RTS", tso->id));
2368 errno = saved_errno;
2373 resumeThread (void *task_)
2377 int saved_errno = errno;
2381 // Wait for permission to re-enter the RTS with the result.
2382 waitForReturnCapability(&cap,task);
2383 // we might be on a different capability now... but if so, our
2384 // entry on the suspended_ccalling_tasks list will also have been
2387 // Remove the thread from the suspended list
2388 recoverSuspendedTask(cap,task);
2390 tso = task->suspended_tso;
2391 task->suspended_tso = NULL;
2392 tso->link = END_TSO_QUEUE;
2393 IF_DEBUG(scheduler, sched_belch("thread %d: re-entering RTS", tso->id));
2395 if (tso->why_blocked == BlockedOnCCall) {
2396 awakenBlockedQueue(cap,tso->blocked_exceptions);
2397 tso->blocked_exceptions = NULL;
2400 /* Reset blocking status */
2401 tso->why_blocked = NotBlocked;
2403 cap->r.rCurrentTSO = tso;
2404 cap->in_haskell = rtsTrue;
2405 errno = saved_errno;
2407 /* We might have GC'd, mark the TSO dirty again */
2410 IF_DEBUG(sanity, checkTSO(tso));
2415 /* ---------------------------------------------------------------------------
2416 * Comparing Thread ids.
2418 * This is used from STG land in the implementation of the
2419 * instances of Eq/Ord for ThreadIds.
2420 * ------------------------------------------------------------------------ */
2423 cmp_thread(StgPtr tso1, StgPtr tso2)
2425 StgThreadID id1 = ((StgTSO *)tso1)->id;
2426 StgThreadID id2 = ((StgTSO *)tso2)->id;
2428 if (id1 < id2) return (-1);
2429 if (id1 > id2) return 1;
2433 /* ---------------------------------------------------------------------------
2434 * Fetching the ThreadID from an StgTSO.
2436 * This is used in the implementation of Show for ThreadIds.
2437 * ------------------------------------------------------------------------ */
2439 rts_getThreadId(StgPtr tso)
2441 return ((StgTSO *)tso)->id;
2446 labelThread(StgPtr tso, char *label)
2451 /* Caveat: Once set, you can only set the thread name to "" */
2452 len = strlen(label)+1;
2453 buf = stgMallocBytes(len * sizeof(char), "Schedule.c:labelThread()");
2454 strncpy(buf,label,len);
2455 /* Update will free the old memory for us */
2456 updateThreadLabel(((StgTSO *)tso)->id,buf);
2460 /* ---------------------------------------------------------------------------
2461 Create a new thread.
2463 The new thread starts with the given stack size. Before the
2464 scheduler can run, however, this thread needs to have a closure
2465 (and possibly some arguments) pushed on its stack. See
2466 pushClosure() in Schedule.h.
2468 createGenThread() and createIOThread() (in SchedAPI.h) are
2469 convenient packaged versions of this function.
2471 currently pri (priority) is only used in a GRAN setup -- HWL
2472 ------------------------------------------------------------------------ */
2474 /* currently pri (priority) is only used in a GRAN setup -- HWL */
2476 createThread(nat size, StgInt pri)
2479 createThread(Capability *cap, nat size)
2485 /* sched_mutex is *not* required */
2487 /* First check whether we should create a thread at all */
2488 #if defined(PARALLEL_HASKELL)
2489 /* check that no more than RtsFlags.ParFlags.maxThreads threads are created */
2490 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads) {
2492 debugBelch("{createThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)\n",
2493 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
2494 return END_TSO_QUEUE;
2500 ASSERT(!RtsFlags.GranFlags.Light || CurrentProc==0);
2503 // ToDo: check whether size = stack_size - TSO_STRUCT_SIZEW
2505 /* catch ridiculously small stack sizes */
2506 if (size < MIN_STACK_WORDS + TSO_STRUCT_SIZEW) {
2507 size = MIN_STACK_WORDS + TSO_STRUCT_SIZEW;
2510 stack_size = size - TSO_STRUCT_SIZEW;
2512 tso = (StgTSO *)allocateLocal(cap, size);
2513 TICK_ALLOC_TSO(stack_size, 0);
2515 SET_HDR(tso, &stg_TSO_info, CCS_SYSTEM);
2517 SET_GRAN_HDR(tso, ThisPE);
2520 // Always start with the compiled code evaluator
2521 tso->what_next = ThreadRunGHC;
2523 tso->why_blocked = NotBlocked;
2524 tso->blocked_exceptions = NULL;
2525 tso->flags = TSO_DIRTY;
2527 tso->saved_errno = 0;
2531 tso->stack_size = stack_size;
2532 tso->max_stack_size = round_to_mblocks(RtsFlags.GcFlags.maxStkSize)
2534 tso->sp = (P_)&(tso->stack) + stack_size;
2536 tso->trec = NO_TREC;
2539 tso->prof.CCCS = CCS_MAIN;
2542 /* put a stop frame on the stack */
2543 tso->sp -= sizeofW(StgStopFrame);
2544 SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_SYSTEM);
2545 tso->link = END_TSO_QUEUE;
2549 /* uses more flexible routine in GranSim */
2550 insertThread(tso, CurrentProc);
2552 /* In a non-GranSim setup the pushing of a TSO onto the runq is separated
2558 if (RtsFlags.GranFlags.GranSimStats.Full)
2559 DumpGranEvent(GR_START,tso);
2560 #elif defined(PARALLEL_HASKELL)
2561 if (RtsFlags.ParFlags.ParStats.Full)
2562 DumpGranEvent(GR_STARTQ,tso);
2563 /* HACk to avoid SCHEDULE
2567 /* Link the new thread on the global thread list.
2569 ACQUIRE_LOCK(&sched_mutex);
2570 tso->id = next_thread_id++; // while we have the mutex
2571 tso->global_link = all_threads;
2573 RELEASE_LOCK(&sched_mutex);
2576 tso->dist.priority = MandatoryPriority; //by default that is...
2580 tso->gran.pri = pri;
2582 tso->gran.magic = TSO_MAGIC; // debugging only
2584 tso->gran.sparkname = 0;
2585 tso->gran.startedat = CURRENT_TIME;
2586 tso->gran.exported = 0;
2587 tso->gran.basicblocks = 0;
2588 tso->gran.allocs = 0;
2589 tso->gran.exectime = 0;
2590 tso->gran.fetchtime = 0;
2591 tso->gran.fetchcount = 0;
2592 tso->gran.blocktime = 0;
2593 tso->gran.blockcount = 0;
2594 tso->gran.blockedat = 0;
2595 tso->gran.globalsparks = 0;
2596 tso->gran.localsparks = 0;
2597 if (RtsFlags.GranFlags.Light)
2598 tso->gran.clock = Now; /* local clock */
2600 tso->gran.clock = 0;
2602 IF_DEBUG(gran,printTSO(tso));
2603 #elif defined(PARALLEL_HASKELL)
2605 tso->par.magic = TSO_MAGIC; // debugging only
2607 tso->par.sparkname = 0;
2608 tso->par.startedat = CURRENT_TIME;
2609 tso->par.exported = 0;
2610 tso->par.basicblocks = 0;
2611 tso->par.allocs = 0;
2612 tso->par.exectime = 0;
2613 tso->par.fetchtime = 0;
2614 tso->par.fetchcount = 0;
2615 tso->par.blocktime = 0;
2616 tso->par.blockcount = 0;
2617 tso->par.blockedat = 0;
2618 tso->par.globalsparks = 0;
2619 tso->par.localsparks = 0;
2623 globalGranStats.tot_threads_created++;
2624 globalGranStats.threads_created_on_PE[CurrentProc]++;
2625 globalGranStats.tot_sq_len += spark_queue_len(CurrentProc);
2626 globalGranStats.tot_sq_probes++;
2627 #elif defined(PARALLEL_HASKELL)
2628 // collect parallel global statistics (currently done together with GC stats)
2629 if (RtsFlags.ParFlags.ParStats.Global &&
2630 RtsFlags.GcFlags.giveStats > NO_GC_STATS) {
2631 //debugBelch("Creating thread %d @ %11.2f\n", tso->id, usertime());
2632 globalParStats.tot_threads_created++;
2638 sched_belch("==__ schedule: Created TSO %d (%p);",
2639 CurrentProc, tso, tso->id));
2640 #elif defined(PARALLEL_HASKELL)
2641 IF_PAR_DEBUG(verbose,
2642 sched_belch("==__ schedule: Created TSO %d (%p); %d threads active",
2643 (long)tso->id, tso, advisory_thread_count));
2645 IF_DEBUG(scheduler,sched_belch("created thread %ld, stack size = %lx words",
2646 (long)tso->id, (long)tso->stack_size));
2653 all parallel thread creation calls should fall through the following routine.
2656 createThreadFromSpark(rtsSpark spark)
2658 ASSERT(spark != (rtsSpark)NULL);
2659 // JB: TAKE CARE OF THIS COUNTER! BUGGY
2660 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads)
2662 barf("{createSparkThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
2663 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
2664 return END_TSO_QUEUE;
2668 tso = createThread(RtsFlags.GcFlags.initialStkSize);
2669 if (tso==END_TSO_QUEUE)
2670 barf("createSparkThread: Cannot create TSO");
2672 tso->priority = AdvisoryPriority;
2674 pushClosure(tso,spark);
2676 advisory_thread_count++; // JB: TAKE CARE OF THIS COUNTER! BUGGY
2683 Turn a spark into a thread.
2684 ToDo: fix for SMP (needs to acquire SCHED_MUTEX!)
2688 activateSpark (rtsSpark spark)
2692 tso = createSparkThread(spark);
2693 if (RtsFlags.ParFlags.ParStats.Full) {
2694 //ASSERT(run_queue_hd == END_TSO_QUEUE); // I think ...
2695 IF_PAR_DEBUG(verbose,
2696 debugBelch("==^^ activateSpark: turning spark of closure %p (%s) into a thread\n",
2697 (StgClosure *)spark, info_type((StgClosure *)spark)));
2699 // ToDo: fwd info on local/global spark to thread -- HWL
2700 // tso->gran.exported = spark->exported;
2701 // tso->gran.locked = !spark->global;
2702 // tso->gran.sparkname = spark->name;
2708 /* ---------------------------------------------------------------------------
2711 * scheduleThread puts a thread on the end of the runnable queue.
2712 * This will usually be done immediately after a thread is created.
2713 * The caller of scheduleThread must create the thread using e.g.
2714 * createThread and push an appropriate closure
2715 * on this thread's stack before the scheduler is invoked.
2716 * ------------------------------------------------------------------------ */
2719 scheduleThread(Capability *cap, StgTSO *tso)
2721 // The thread goes at the *end* of the run-queue, to avoid possible
2722 // starvation of any threads already on the queue.
2723 appendToRunQueue(cap,tso);
2727 scheduleThreadOn(Capability *cap, StgWord cpu USED_IF_THREADS, StgTSO *tso)
2729 #if defined(THREADED_RTS)
2730 tso->flags |= TSO_LOCKED; // we requested explicit affinity; don't
2731 // move this thread from now on.
2732 cpu %= RtsFlags.ParFlags.nNodes;
2733 if (cpu == cap->no) {
2734 appendToRunQueue(cap,tso);
2736 Capability *target_cap = &capabilities[cpu];
2738 tso->bound->cap = target_cap;
2740 tso->cap = target_cap;
2741 wakeupThreadOnCapability(target_cap,tso);
2744 appendToRunQueue(cap,tso);
2749 scheduleWaitThread (StgTSO* tso, /*[out]*/HaskellObj* ret, Capability *cap)
2753 // We already created/initialised the Task
2754 task = cap->running_task;
2756 // This TSO is now a bound thread; make the Task and TSO
2757 // point to each other.
2763 task->stat = NoStatus;
2765 appendToRunQueue(cap,tso);
2767 IF_DEBUG(scheduler, sched_belch("new bound thread (%d)", tso->id));
2770 /* GranSim specific init */
2771 CurrentTSO = m->tso; // the TSO to run
2772 procStatus[MainProc] = Busy; // status of main PE
2773 CurrentProc = MainProc; // PE to run it on
2776 cap = schedule(cap,task);
2778 ASSERT(task->stat != NoStatus);
2779 ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
2781 IF_DEBUG(scheduler, sched_belch("bound thread (%d) finished", task->tso->id));
2785 /* ----------------------------------------------------------------------------
2787 * ------------------------------------------------------------------------- */
2789 #if defined(THREADED_RTS)
2791 workerStart(Task *task)
2795 // See startWorkerTask().
2796 ACQUIRE_LOCK(&task->lock);
2798 RELEASE_LOCK(&task->lock);
2800 // set the thread-local pointer to the Task:
2803 // schedule() runs without a lock.
2804 cap = schedule(cap,task);
2806 // On exit from schedule(), we have a Capability.
2807 releaseCapability(cap);
2812 /* ---------------------------------------------------------------------------
2815 * Initialise the scheduler. This resets all the queues - if the
2816 * queues contained any threads, they'll be garbage collected at the
2819 * ------------------------------------------------------------------------ */
2826 for (i=0; i<=MAX_PROC; i++) {
2827 run_queue_hds[i] = END_TSO_QUEUE;
2828 run_queue_tls[i] = END_TSO_QUEUE;
2829 blocked_queue_hds[i] = END_TSO_QUEUE;
2830 blocked_queue_tls[i] = END_TSO_QUEUE;
2831 ccalling_threadss[i] = END_TSO_QUEUE;
2832 blackhole_queue[i] = END_TSO_QUEUE;
2833 sleeping_queue = END_TSO_QUEUE;
2835 #elif !defined(THREADED_RTS)
2836 blocked_queue_hd = END_TSO_QUEUE;
2837 blocked_queue_tl = END_TSO_QUEUE;
2838 sleeping_queue = END_TSO_QUEUE;
2841 blackhole_queue = END_TSO_QUEUE;
2842 all_threads = END_TSO_QUEUE;
2845 sched_state = SCHED_RUNNING;
2847 RtsFlags.ConcFlags.ctxtSwitchTicks =
2848 RtsFlags.ConcFlags.ctxtSwitchTime / TICK_MILLISECS;
2850 #if defined(THREADED_RTS)
2851 /* Initialise the mutex and condition variables used by
2853 initMutex(&sched_mutex);
2856 ACQUIRE_LOCK(&sched_mutex);
2858 /* A capability holds the state a native thread needs in
2859 * order to execute STG code. At least one capability is
2860 * floating around (only THREADED_RTS builds have more than one).
2866 #if defined(THREADED_RTS) || defined(PARALLEL_HASKELL)
2870 #if defined(THREADED_RTS)
2872 * Eagerly start one worker to run each Capability, except for
2873 * Capability 0. The idea is that we're probably going to start a
2874 * bound thread on Capability 0 pretty soon, so we don't want a
2875 * worker task hogging it.
2880 for (i = 1; i < n_capabilities; i++) {
2881 cap = &capabilities[i];
2882 ACQUIRE_LOCK(&cap->lock);
2883 startWorkerTask(cap, workerStart);
2884 RELEASE_LOCK(&cap->lock);
2889 RELEASE_LOCK(&sched_mutex);
2893 exitScheduler( void )
2897 #if defined(THREADED_RTS)
2898 ACQUIRE_LOCK(&sched_mutex);
2899 task = newBoundTask();
2900 RELEASE_LOCK(&sched_mutex);
2903 // If we haven't killed all the threads yet, do it now.
2904 if (sched_state < SCHED_INTERRUPTED) {
2905 sched_state = SCHED_INTERRUPTING;
2906 scheduleDoGC(NULL,task,rtsFalse,GetRoots);
2908 sched_state = SCHED_SHUTTING_DOWN;
2910 #if defined(THREADED_RTS)
2914 for (i = 0; i < n_capabilities; i++) {
2915 shutdownCapability(&capabilities[i], task);
2917 boundTaskExiting(task);
2923 /* ---------------------------------------------------------------------------
2924 Where are the roots that we know about?
2926 - all the threads on the runnable queue
2927 - all the threads on the blocked queue
2928 - all the threads on the sleeping queue
2929 - all the thread currently executing a _ccall_GC
2930 - all the "main threads"
2932 ------------------------------------------------------------------------ */
2934 /* This has to be protected either by the scheduler monitor, or by the
2935 garbage collection monitor (probably the latter).
2940 GetRoots( evac_fn evac )
2947 for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
2948 if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
2949 evac((StgClosure **)&run_queue_hds[i]);
2950 if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
2951 evac((StgClosure **)&run_queue_tls[i]);
2953 if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
2954 evac((StgClosure **)&blocked_queue_hds[i]);
2955 if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
2956 evac((StgClosure **)&blocked_queue_tls[i]);
2957 if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
2958 evac((StgClosure **)&ccalling_threads[i]);
2965 for (i = 0; i < n_capabilities; i++) {
2966 cap = &capabilities[i];
2967 evac((StgClosure **)(void *)&cap->run_queue_hd);
2968 evac((StgClosure **)(void *)&cap->run_queue_tl);
2969 #if defined(THREADED_RTS)
2970 evac((StgClosure **)(void *)&cap->wakeup_queue_hd);
2971 evac((StgClosure **)(void *)&cap->wakeup_queue_tl);
2973 for (task = cap->suspended_ccalling_tasks; task != NULL;
2975 IF_DEBUG(scheduler,sched_belch("evac'ing suspended TSO %d", task->suspended_tso->id));
2976 evac((StgClosure **)(void *)&task->suspended_tso);
2982 #if !defined(THREADED_RTS)
2983 evac((StgClosure **)(void *)&blocked_queue_hd);
2984 evac((StgClosure **)(void *)&blocked_queue_tl);
2985 evac((StgClosure **)(void *)&sleeping_queue);
2989 // evac((StgClosure **)&blackhole_queue);
2991 #if defined(THREADED_RTS) || defined(PARALLEL_HASKELL) || defined(GRAN)
2992 markSparkQueue(evac);
2995 #if defined(RTS_USER_SIGNALS)
2996 // mark the signal handlers (signals should be already blocked)
2997 markSignalHandlers(evac);
3001 /* -----------------------------------------------------------------------------
3004 This is the interface to the garbage collector from Haskell land.
3005 We provide this so that external C code can allocate and garbage
3006 collect when called from Haskell via _ccall_GC.
3008 It might be useful to provide an interface whereby the programmer
3009 can specify more roots (ToDo).
3011 This needs to be protected by the GC condition variable above. KH.
3012 -------------------------------------------------------------------------- */
3014 static void (*extra_roots)(evac_fn);
3017 performGC_(rtsBool force_major, void (*get_roots)(evac_fn))
3019 Task *task = myTask();
3022 ACQUIRE_LOCK(&sched_mutex);
3023 task = newBoundTask();
3024 RELEASE_LOCK(&sched_mutex);
3025 scheduleDoGC(NULL,task,force_major, get_roots);
3026 boundTaskExiting(task);
3028 scheduleDoGC(NULL,task,force_major, get_roots);
3035 performGC_(rtsFalse, GetRoots);
3039 performMajorGC(void)
3041 performGC_(rtsTrue, GetRoots);
3045 AllRoots(evac_fn evac)
3047 GetRoots(evac); // the scheduler's roots
3048 extra_roots(evac); // the user's roots
3052 performGCWithRoots(void (*get_roots)(evac_fn))
3054 extra_roots = get_roots;
3055 performGC_(rtsFalse, AllRoots);
3058 /* -----------------------------------------------------------------------------
3061 If the thread has reached its maximum stack size, then raise the
3062 StackOverflow exception in the offending thread. Otherwise
3063 relocate the TSO into a larger chunk of memory and adjust its stack
3065 -------------------------------------------------------------------------- */
3068 threadStackOverflow(Capability *cap, StgTSO *tso)
3070 nat new_stack_size, stack_words;
3075 IF_DEBUG(sanity,checkTSO(tso));
3076 if (tso->stack_size >= tso->max_stack_size) {
3079 debugBelch("@@ threadStackOverflow of TSO %ld (%p): stack too large (now %ld; max is %ld)\n",
3080 (long)tso->id, tso, (long)tso->stack_size, (long)tso->max_stack_size);
3081 /* If we're debugging, just print out the top of the stack */
3082 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
3085 /* Send this thread the StackOverflow exception */
3086 raiseAsync(cap, tso, (StgClosure *)stackOverflow_closure);
3090 /* Try to double the current stack size. If that takes us over the
3091 * maximum stack size for this thread, then use the maximum instead.
3092 * Finally round up so the TSO ends up as a whole number of blocks.
3094 new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
3095 new_tso_size = (lnat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
3096 TSO_STRUCT_SIZE)/sizeof(W_);
3097 new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
3098 new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
3100 IF_DEBUG(scheduler, sched_belch("increasing stack size from %ld words to %d.\n", (long)tso->stack_size, new_stack_size));
3102 dest = (StgTSO *)allocate(new_tso_size);
3103 TICK_ALLOC_TSO(new_stack_size,0);
3105 /* copy the TSO block and the old stack into the new area */
3106 memcpy(dest,tso,TSO_STRUCT_SIZE);
3107 stack_words = tso->stack + tso->stack_size - tso->sp;
3108 new_sp = (P_)dest + new_tso_size - stack_words;
3109 memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
3111 /* relocate the stack pointers... */
3113 dest->stack_size = new_stack_size;
3115 /* Mark the old TSO as relocated. We have to check for relocated
3116 * TSOs in the garbage collector and any primops that deal with TSOs.
3118 * It's important to set the sp value to just beyond the end
3119 * of the stack, so we don't attempt to scavenge any part of the
3122 tso->what_next = ThreadRelocated;
3124 tso->sp = (P_)&(tso->stack[tso->stack_size]);
3125 tso->why_blocked = NotBlocked;
3127 IF_PAR_DEBUG(verbose,
3128 debugBelch("@@ threadStackOverflow of TSO %d (now at %p): stack size increased to %ld\n",
3129 tso->id, tso, tso->stack_size);
3130 /* If we're debugging, just print out the top of the stack */
3131 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
3134 IF_DEBUG(sanity,checkTSO(tso));
3136 IF_DEBUG(scheduler,printTSO(dest));
3142 /* ---------------------------------------------------------------------------
3143 Wake up a queue that was blocked on some resource.
3144 ------------------------------------------------------------------------ */
3148 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
3151 #elif defined(PARALLEL_HASKELL)
3153 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
3155 /* write RESUME events to log file and
3156 update blocked and fetch time (depending on type of the orig closure) */
3157 if (RtsFlags.ParFlags.ParStats.Full) {
3158 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
3159 GR_RESUMEQ, ((StgTSO *)bqe), ((StgTSO *)bqe)->block_info.closure,
3160 0, 0 /* spark_queue_len(ADVISORY_POOL) */);
3161 if (emptyRunQueue())
3162 emitSchedule = rtsTrue;
3164 switch (get_itbl(node)->type) {
3166 ((StgTSO *)bqe)->par.fetchtime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
3171 ((StgTSO *)bqe)->par.blocktime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
3178 barf("{unblockOne}Daq Qagh: unexpected closure in blocking queue");
3185 StgBlockingQueueElement *
3186 unblockOne(StgBlockingQueueElement *bqe, StgClosure *node)
3189 PEs node_loc, tso_loc;
3191 node_loc = where_is(node); // should be lifted out of loop
3192 tso = (StgTSO *)bqe; // wastes an assignment to get the type right
3193 tso_loc = where_is((StgClosure *)tso);
3194 if (IS_LOCAL_TO(PROCS(node),tso_loc)) { // TSO is local
3195 /* !fake_fetch => TSO is on CurrentProc is same as IS_LOCAL_TO */
3196 ASSERT(CurrentProc!=node_loc || tso_loc==CurrentProc);
3197 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.lunblocktime;
3198 // insertThread(tso, node_loc);
3199 new_event(tso_loc, tso_loc, CurrentTime[CurrentProc],
3201 tso, node, (rtsSpark*)NULL);
3202 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
3205 } else { // TSO is remote (actually should be FMBQ)
3206 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.mpacktime +
3207 RtsFlags.GranFlags.Costs.gunblocktime +
3208 RtsFlags.GranFlags.Costs.latency;
3209 new_event(tso_loc, CurrentProc, CurrentTime[CurrentProc],
3211 tso, node, (rtsSpark*)NULL);
3212 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
3215 /* the thread-queue-overhead is accounted for in either Resume or UnblockThread */
3217 debugBelch(" %s TSO %d (%p) [PE %d] (block_info.closure=%p) (next=%p) ,",
3218 (node_loc==tso_loc ? "Local" : "Global"),
3219 tso->id, tso, CurrentProc, tso->block_info.closure, tso->link));
3220 tso->block_info.closure = NULL;
3221 IF_DEBUG(scheduler,debugBelch("-- Waking up thread %ld (%p)\n",
3224 #elif defined(PARALLEL_HASKELL)
3225 StgBlockingQueueElement *
3226 unblockOne(StgBlockingQueueElement *bqe, StgClosure *node)
3228 StgBlockingQueueElement *next;
3230 switch (get_itbl(bqe)->type) {
3232 ASSERT(((StgTSO *)bqe)->why_blocked != NotBlocked);
3233 /* if it's a TSO just push it onto the run_queue */
3235 ((StgTSO *)bqe)->link = END_TSO_QUEUE; // debugging?
3236 APPEND_TO_RUN_QUEUE((StgTSO *)bqe);
3238 unblockCount(bqe, node);
3239 /* reset blocking status after dumping event */
3240 ((StgTSO *)bqe)->why_blocked = NotBlocked;
3244 /* if it's a BLOCKED_FETCH put it on the PendingFetches list */
3246 bqe->link = (StgBlockingQueueElement *)PendingFetches;
3247 PendingFetches = (StgBlockedFetch *)bqe;
3251 /* can ignore this case in a non-debugging setup;
3252 see comments on RBHSave closures above */
3254 /* check that the closure is an RBHSave closure */
3255 ASSERT(get_itbl((StgClosure *)bqe) == &stg_RBH_Save_0_info ||
3256 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_1_info ||
3257 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_2_info);
3261 barf("{unblockOne}Daq Qagh: Unexpected IP (%#lx; %s) in blocking queue at %#lx\n",
3262 get_itbl((StgClosure *)bqe), info_type((StgClosure *)bqe),
3266 IF_PAR_DEBUG(bq, debugBelch(", %p (%s)\n", bqe, info_type((StgClosure*)bqe)));
3272 unblockOne(Capability *cap, StgTSO *tso)
3276 ASSERT(get_itbl(tso)->type == TSO);
3277 ASSERT(tso->why_blocked != NotBlocked);
3279 tso->why_blocked = NotBlocked;
3281 tso->link = END_TSO_QUEUE;
3283 #if defined(THREADED_RTS)
3284 if (tso->cap == cap || (!tsoLocked(tso) && RtsFlags.ParFlags.wakeupMigrate)) {
3285 // We are waking up this thread on the current Capability, which
3286 // might involve migrating it from the Capability it was last on.
3288 ASSERT(tso->bound->cap == tso->cap);
3289 tso->bound->cap = cap;
3292 appendToRunQueue(cap,tso);
3293 // we're holding a newly woken thread, make sure we context switch
3294 // quickly so we can migrate it if necessary.
3297 // we'll try to wake it up on the Capability it was last on.
3298 wakeupThreadOnCapability(tso->cap, tso);
3301 appendToRunQueue(cap,tso);
3305 IF_DEBUG(scheduler,sched_belch("waking up thread %ld on cap %d", (long)tso->id, tso->cap->no));
3312 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
3314 StgBlockingQueueElement *bqe;
3319 debugBelch("##-_ AwBQ for node %p on PE %d @ %ld by TSO %d (%p): \n", \
3320 node, CurrentProc, CurrentTime[CurrentProc],
3321 CurrentTSO->id, CurrentTSO));
3323 node_loc = where_is(node);
3325 ASSERT(q == END_BQ_QUEUE ||
3326 get_itbl(q)->type == TSO || // q is either a TSO or an RBHSave
3327 get_itbl(q)->type == CONSTR); // closure (type constructor)
3328 ASSERT(is_unique(node));
3330 /* FAKE FETCH: magically copy the node to the tso's proc;
3331 no Fetch necessary because in reality the node should not have been
3332 moved to the other PE in the first place
3334 if (CurrentProc!=node_loc) {
3336 debugBelch("## node %p is on PE %d but CurrentProc is %d (TSO %d); assuming fake fetch and adjusting bitmask (old: %#x)\n",
3337 node, node_loc, CurrentProc, CurrentTSO->id,
3338 // CurrentTSO, where_is(CurrentTSO),
3339 node->header.gran.procs));
3340 node->header.gran.procs = (node->header.gran.procs) | PE_NUMBER(CurrentProc);
3342 debugBelch("## new bitmask of node %p is %#x\n",
3343 node, node->header.gran.procs));
3344 if (RtsFlags.GranFlags.GranSimStats.Global) {
3345 globalGranStats.tot_fake_fetches++;
3350 // ToDo: check: ASSERT(CurrentProc==node_loc);
3351 while (get_itbl(bqe)->type==TSO) { // q != END_TSO_QUEUE) {
3354 bqe points to the current element in the queue
3355 next points to the next element in the queue
3357 //tso = (StgTSO *)bqe; // wastes an assignment to get the type right
3358 //tso_loc = where_is(tso);
3360 bqe = unblockOne(bqe, node);
3363 /* if this is the BQ of an RBH, we have to put back the info ripped out of
3364 the closure to make room for the anchor of the BQ */
3365 if (bqe!=END_BQ_QUEUE) {
3366 ASSERT(get_itbl(node)->type == RBH && get_itbl(bqe)->type == CONSTR);
3368 ASSERT((info_ptr==&RBH_Save_0_info) ||
3369 (info_ptr==&RBH_Save_1_info) ||
3370 (info_ptr==&RBH_Save_2_info));
3372 /* cf. convertToRBH in RBH.c for writing the RBHSave closure */
3373 ((StgRBH *)node)->blocking_queue = (StgBlockingQueueElement *)((StgRBHSave *)bqe)->payload[0];
3374 ((StgRBH *)node)->mut_link = (StgMutClosure *)((StgRBHSave *)bqe)->payload[1];
3377 debugBelch("## Filled in RBH_Save for %p (%s) at end of AwBQ\n",
3378 node, info_type(node)));
3381 /* statistics gathering */
3382 if (RtsFlags.GranFlags.GranSimStats.Global) {
3383 // globalGranStats.tot_bq_processing_time += bq_processing_time;
3384 globalGranStats.tot_bq_len += len; // total length of all bqs awakened
3385 // globalGranStats.tot_bq_len_local += len_local; // same for local TSOs only
3386 globalGranStats.tot_awbq++; // total no. of bqs awakened
3389 debugBelch("## BQ Stats of %p: [%d entries] %s\n",
3390 node, len, (bqe!=END_BQ_QUEUE) ? "RBH" : ""));
3392 #elif defined(PARALLEL_HASKELL)
3394 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
3396 StgBlockingQueueElement *bqe;
3398 IF_PAR_DEBUG(verbose,
3399 debugBelch("##-_ AwBQ for node %p on [%x]: \n",
3403 if(get_itbl(q)->type == CONSTR || q==END_BQ_QUEUE) {
3404 IF_PAR_DEBUG(verbose, debugBelch("## ... nothing to unblock so lets just return. RFP (BUG?)\n"));
3409 ASSERT(q == END_BQ_QUEUE ||
3410 get_itbl(q)->type == TSO ||
3411 get_itbl(q)->type == BLOCKED_FETCH ||
3412 get_itbl(q)->type == CONSTR);
3415 while (get_itbl(bqe)->type==TSO ||
3416 get_itbl(bqe)->type==BLOCKED_FETCH) {
3417 bqe = unblockOne(bqe, node);
3421 #else /* !GRAN && !PARALLEL_HASKELL */
3424 awakenBlockedQueue(Capability *cap, StgTSO *tso)
3426 if (tso == NULL) return; // hack; see bug #1235728, and comments in
3428 while (tso != END_TSO_QUEUE) {
3429 tso = unblockOne(cap,tso);
3434 /* ---------------------------------------------------------------------------
3436 - usually called inside a signal handler so it mustn't do anything fancy.
3437 ------------------------------------------------------------------------ */
3440 interruptStgRts(void)
3442 sched_state = SCHED_INTERRUPTING;
3444 #if defined(THREADED_RTS)
3445 prodAllCapabilities();
3449 /* -----------------------------------------------------------------------------
3452 This is for use when we raise an exception in another thread, which
3454 This has nothing to do with the UnblockThread event in GranSim. -- HWL
3455 -------------------------------------------------------------------------- */
3457 #if defined(GRAN) || defined(PARALLEL_HASKELL)
3459 NB: only the type of the blocking queue is different in GranSim and GUM
3460 the operations on the queue-elements are the same
3461 long live polymorphism!
3463 Locks: sched_mutex is held upon entry and exit.
3467 unblockThread(Capability *cap, StgTSO *tso)
3469 StgBlockingQueueElement *t, **last;
3471 switch (tso->why_blocked) {
3474 return; /* not blocked */
3477 // Be careful: nothing to do here! We tell the scheduler that the thread
3478 // is runnable and we leave it to the stack-walking code to abort the
3479 // transaction while unwinding the stack. We should perhaps have a debugging
3480 // test to make sure that this really happens and that the 'zombie' transaction
3481 // does not get committed.
3485 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
3487 StgBlockingQueueElement *last_tso = END_BQ_QUEUE;
3488 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
3490 last = (StgBlockingQueueElement **)&mvar->head;
3491 for (t = (StgBlockingQueueElement *)mvar->head;
3493 last = &t->link, last_tso = t, t = t->link) {
3494 if (t == (StgBlockingQueueElement *)tso) {
3495 *last = (StgBlockingQueueElement *)tso->link;
3496 if (mvar->tail == tso) {
3497 mvar->tail = (StgTSO *)last_tso;
3502 barf("unblockThread (MVAR): TSO not found");
3505 case BlockedOnBlackHole:
3506 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
3508 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
3510 last = &bq->blocking_queue;
3511 for (t = bq->blocking_queue;
3513 last = &t->link, t = t->link) {
3514 if (t == (StgBlockingQueueElement *)tso) {
3515 *last = (StgBlockingQueueElement *)tso->link;
3519 barf("unblockThread (BLACKHOLE): TSO not found");
3522 case BlockedOnException:
3524 StgTSO *target = tso->block_info.tso;
3526 ASSERT(get_itbl(target)->type == TSO);
3528 if (target->what_next == ThreadRelocated) {
3529 target = target->link;
3530 ASSERT(get_itbl(target)->type == TSO);
3533 ASSERT(target->blocked_exceptions != NULL);
3535 last = (StgBlockingQueueElement **)&target->blocked_exceptions;
3536 for (t = (StgBlockingQueueElement *)target->blocked_exceptions;
3538 last = &t->link, t = t->link) {
3539 ASSERT(get_itbl(t)->type == TSO);
3540 if (t == (StgBlockingQueueElement *)tso) {
3541 *last = (StgBlockingQueueElement *)tso->link;
3545 barf("unblockThread (Exception): TSO not found");
3549 case BlockedOnWrite:
3550 #if defined(mingw32_HOST_OS)
3551 case BlockedOnDoProc:
3554 /* take TSO off blocked_queue */
3555 StgBlockingQueueElement *prev = NULL;
3556 for (t = (StgBlockingQueueElement *)blocked_queue_hd; t != END_BQ_QUEUE;
3557 prev = t, t = t->link) {
3558 if (t == (StgBlockingQueueElement *)tso) {
3560 blocked_queue_hd = (StgTSO *)t->link;
3561 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
3562 blocked_queue_tl = END_TSO_QUEUE;
3565 prev->link = t->link;
3566 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
3567 blocked_queue_tl = (StgTSO *)prev;
3570 #if defined(mingw32_HOST_OS)
3571 /* (Cooperatively) signal that the worker thread should abort
3574 abandonWorkRequest(tso->block_info.async_result->reqID);
3579 barf("unblockThread (I/O): TSO not found");
3582 case BlockedOnDelay:
3584 /* take TSO off sleeping_queue */
3585 StgBlockingQueueElement *prev = NULL;
3586 for (t = (StgBlockingQueueElement *)sleeping_queue; t != END_BQ_QUEUE;
3587 prev = t, t = t->link) {
3588 if (t == (StgBlockingQueueElement *)tso) {
3590 sleeping_queue = (StgTSO *)t->link;
3592 prev->link = t->link;
3597 barf("unblockThread (delay): TSO not found");
3601 barf("unblockThread");
3605 tso->link = END_TSO_QUEUE;
3606 tso->why_blocked = NotBlocked;
3607 tso->block_info.closure = NULL;
3608 pushOnRunQueue(cap,tso);
3612 unblockThread(Capability *cap, StgTSO *tso)
3616 /* To avoid locking unnecessarily. */
3617 if (tso->why_blocked == NotBlocked) {
3621 switch (tso->why_blocked) {
3624 // Be careful: nothing to do here! We tell the scheduler that the thread
3625 // is runnable and we leave it to the stack-walking code to abort the
3626 // transaction while unwinding the stack. We should perhaps have a debugging
3627 // test to make sure that this really happens and that the 'zombie' transaction
3628 // does not get committed.
3632 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
3634 StgTSO *last_tso = END_TSO_QUEUE;
3635 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
3638 for (t = mvar->head; t != END_TSO_QUEUE;
3639 last = &t->link, last_tso = t, t = t->link) {
3642 if (mvar->tail == tso) {
3643 mvar->tail = last_tso;
3648 barf("unblockThread (MVAR): TSO not found");
3651 case BlockedOnBlackHole:
3653 last = &blackhole_queue;
3654 for (t = blackhole_queue; t != END_TSO_QUEUE;
3655 last = &t->link, t = t->link) {
3661 barf("unblockThread (BLACKHOLE): TSO not found");
3664 case BlockedOnException:
3666 StgTSO *target = tso->block_info.tso;
3668 ASSERT(get_itbl(target)->type == TSO);
3670 while (target->what_next == ThreadRelocated) {
3671 target = target->link;
3672 ASSERT(get_itbl(target)->type == TSO);
3675 ASSERT(target->blocked_exceptions != NULL);
3677 last = &target->blocked_exceptions;
3678 for (t = target->blocked_exceptions; t != END_TSO_QUEUE;
3679 last = &t->link, t = t->link) {
3680 ASSERT(get_itbl(t)->type == TSO);
3686 barf("unblockThread (Exception): TSO not found");
3689 #if !defined(THREADED_RTS)
3691 case BlockedOnWrite:
3692 #if defined(mingw32_HOST_OS)
3693 case BlockedOnDoProc:
3696 StgTSO *prev = NULL;
3697 for (t = blocked_queue_hd; t != END_TSO_QUEUE;
3698 prev = t, t = t->link) {
3701 blocked_queue_hd = t->link;
3702 if (blocked_queue_tl == t) {
3703 blocked_queue_tl = END_TSO_QUEUE;
3706 prev->link = t->link;
3707 if (blocked_queue_tl == t) {
3708 blocked_queue_tl = prev;
3711 #if defined(mingw32_HOST_OS)
3712 /* (Cooperatively) signal that the worker thread should abort
3715 abandonWorkRequest(tso->block_info.async_result->reqID);
3720 barf("unblockThread (I/O): TSO not found");
3723 case BlockedOnDelay:
3725 StgTSO *prev = NULL;
3726 for (t = sleeping_queue; t != END_TSO_QUEUE;
3727 prev = t, t = t->link) {
3730 sleeping_queue = t->link;
3732 prev->link = t->link;
3737 barf("unblockThread (delay): TSO not found");
3742 barf("unblockThread");
3746 tso->link = END_TSO_QUEUE;
3747 tso->why_blocked = NotBlocked;
3748 tso->block_info.closure = NULL;
3749 appendToRunQueue(cap,tso);
3751 // We might have just migrated this TSO to our Capability:
3753 tso->bound->cap = cap;
3759 /* -----------------------------------------------------------------------------
3762 * Check the blackhole_queue for threads that can be woken up. We do
3763 * this periodically: before every GC, and whenever the run queue is
3766 * An elegant solution might be to just wake up all the blocked
3767 * threads with awakenBlockedQueue occasionally: they'll go back to
3768 * sleep again if the object is still a BLACKHOLE. Unfortunately this
3769 * doesn't give us a way to tell whether we've actually managed to
3770 * wake up any threads, so we would be busy-waiting.
3772 * -------------------------------------------------------------------------- */
3775 checkBlackHoles (Capability *cap)
3778 rtsBool any_woke_up = rtsFalse;
3781 // blackhole_queue is global:
3782 ASSERT_LOCK_HELD(&sched_mutex);
3784 IF_DEBUG(scheduler, sched_belch("checking threads blocked on black holes"));
3786 // ASSUMES: sched_mutex
3787 prev = &blackhole_queue;
3788 t = blackhole_queue;
3789 while (t != END_TSO_QUEUE) {
3790 ASSERT(t->why_blocked == BlockedOnBlackHole);
3791 type = get_itbl(t->block_info.closure)->type;
3792 if (type != BLACKHOLE && type != CAF_BLACKHOLE) {
3793 IF_DEBUG(sanity,checkTSO(t));
3794 t = unblockOne(cap, t);
3795 // urk, the threads migrate to the current capability
3796 // here, but we'd like to keep them on the original one.
3798 any_woke_up = rtsTrue;
3808 /* -----------------------------------------------------------------------------
3811 * The following function implements the magic for raising an
3812 * asynchronous exception in an existing thread.
3814 * We first remove the thread from any queue on which it might be
3815 * blocked. The possible blockages are MVARs and BLACKHOLE_BQs.
3817 * We strip the stack down to the innermost CATCH_FRAME, building
3818 * thunks in the heap for all the active computations, so they can
3819 * be restarted if necessary. When we reach a CATCH_FRAME, we build
3820 * an application of the handler to the exception, and push it on
3821 * the top of the stack.
3823 * How exactly do we save all the active computations? We create an
3824 * AP_STACK for every UpdateFrame on the stack. Entering one of these
3825 * AP_STACKs pushes everything from the corresponding update frame
3826 * upwards onto the stack. (Actually, it pushes everything up to the
3827 * next update frame plus a pointer to the next AP_STACK object.
3828 * Entering the next AP_STACK object pushes more onto the stack until we
3829 * reach the last AP_STACK object - at which point the stack should look
3830 * exactly as it did when we killed the TSO and we can continue
3831 * execution by entering the closure on top of the stack.
3833 * We can also kill a thread entirely - this happens if either (a) the
3834 * exception passed to raiseAsync is NULL, or (b) there's no
3835 * CATCH_FRAME on the stack. In either case, we strip the entire
3836 * stack and replace the thread with a zombie.
3838 * ToDo: in THREADED_RTS mode, this function is only safe if either
3839 * (a) we hold all the Capabilities (eg. in GC, or if there is only
3840 * one Capability), or (b) we own the Capability that the TSO is
3841 * currently blocked on or on the run queue of.
3843 * -------------------------------------------------------------------------- */
3846 raiseAsync(Capability *cap, StgTSO *tso, StgClosure *exception)
3848 raiseAsync_(cap, tso, exception, rtsFalse, NULL);
3852 suspendComputation(Capability *cap, StgTSO *tso, StgPtr stop_here)
3854 raiseAsync_(cap, tso, NULL, rtsFalse, stop_here);
3858 raiseAsync_(Capability *cap, StgTSO *tso, StgClosure *exception,
3859 rtsBool stop_at_atomically, StgPtr stop_here)
3861 StgRetInfoTable *info;
3865 // Thread already dead?
3866 if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) {
3871 sched_belch("raising exception in thread %ld.", (long)tso->id));
3873 // Remove it from any blocking queues
3874 unblockThread(cap,tso);
3876 // mark it dirty; we're about to change its stack.
3881 // The stack freezing code assumes there's a closure pointer on
3882 // the top of the stack, so we have to arrange that this is the case...
3884 if (sp[0] == (W_)&stg_enter_info) {
3888 sp[0] = (W_)&stg_dummy_ret_closure;
3892 while (stop_here == NULL || frame < stop_here) {
3894 // 1. Let the top of the stack be the "current closure"
3896 // 2. Walk up the stack until we find either an UPDATE_FRAME or a
3899 // 3. If it's an UPDATE_FRAME, then make an AP_STACK containing the
3900 // current closure applied to the chunk of stack up to (but not
3901 // including) the update frame. This closure becomes the "current
3902 // closure". Go back to step 2.
3904 // 4. If it's a CATCH_FRAME, then leave the exception handler on
3905 // top of the stack applied to the exception.
3907 // 5. If it's a STOP_FRAME, then kill the thread.
3909 // NB: if we pass an ATOMICALLY_FRAME then abort the associated
3912 info = get_ret_itbl((StgClosure *)frame);
3914 switch (info->i.type) {
3921 // First build an AP_STACK consisting of the stack chunk above the
3922 // current update frame, with the top word on the stack as the
3925 words = frame - sp - 1;
3926 ap = (StgAP_STACK *)allocateLocal(cap,AP_STACK_sizeW(words));
3929 ap->fun = (StgClosure *)sp[0];
3931 for(i=0; i < (nat)words; ++i) {
3932 ap->payload[i] = (StgClosure *)*sp++;
3935 SET_HDR(ap,&stg_AP_STACK_info,
3936 ((StgClosure *)frame)->header.prof.ccs /* ToDo */);
3937 TICK_ALLOC_UP_THK(words+1,0);
3940 debugBelch("sched: Updating ");
3941 printPtr((P_)((StgUpdateFrame *)frame)->updatee);
3942 debugBelch(" with ");
3943 printObj((StgClosure *)ap);
3946 // Replace the updatee with an indirection
3948 // Warning: if we're in a loop, more than one update frame on
3949 // the stack may point to the same object. Be careful not to
3950 // overwrite an IND_OLDGEN in this case, because we'll screw
3951 // up the mutable lists. To be on the safe side, don't
3952 // overwrite any kind of indirection at all. See also
3953 // threadSqueezeStack in GC.c, where we have to make a similar
3956 if (!closure_IND(((StgUpdateFrame *)frame)->updatee)) {
3957 // revert the black hole
3958 UPD_IND_NOLOCK(((StgUpdateFrame *)frame)->updatee,
3961 sp += sizeofW(StgUpdateFrame) - 1;
3962 sp[0] = (W_)ap; // push onto stack
3964 continue; //no need to bump frame
3968 // We've stripped the entire stack, the thread is now dead.
3969 tso->what_next = ThreadKilled;
3970 tso->sp = frame + sizeofW(StgStopFrame);
3974 // If we find a CATCH_FRAME, and we've got an exception to raise,
3975 // then build the THUNK raise(exception), and leave it on
3976 // top of the CATCH_FRAME ready to enter.
3980 StgCatchFrame *cf = (StgCatchFrame *)frame;
3984 if (exception == NULL) break;
3986 // we've got an exception to raise, so let's pass it to the
3987 // handler in this frame.
3989 raise = (StgThunk *)allocateLocal(cap,sizeofW(StgThunk)+1);
3990 TICK_ALLOC_SE_THK(1,0);
3991 SET_HDR(raise,&stg_raise_info,cf->header.prof.ccs);
3992 raise->payload[0] = exception;
3994 // throw away the stack from Sp up to the CATCH_FRAME.
3998 /* Ensure that async excpetions are blocked now, so we don't get
3999 * a surprise exception before we get around to executing the
4002 if (tso->blocked_exceptions == NULL) {
4003 tso->blocked_exceptions = END_TSO_QUEUE;
4006 /* Put the newly-built THUNK on top of the stack, ready to execute
4007 * when the thread restarts.
4010 sp[-1] = (W_)&stg_enter_info;
4012 tso->what_next = ThreadRunGHC;
4013 IF_DEBUG(sanity, checkTSO(tso));
4017 case ATOMICALLY_FRAME:
4018 if (stop_at_atomically) {
4019 ASSERT(stmGetEnclosingTRec(tso->trec) == NO_TREC);
4020 stmCondemnTransaction(cap, tso -> trec);
4024 // R1 is not a register: the return convention for IO in
4025 // this case puts the return value on the stack, so we
4026 // need to set up the stack to return to the atomically
4027 // frame properly...
4028 tso->sp = frame - 2;
4029 tso->sp[1] = (StgWord) &stg_NO_FINALIZER_closure; // why not?
4030 tso->sp[0] = (StgWord) &stg_ut_1_0_unreg_info;
4032 tso->what_next = ThreadRunGHC;
4035 // Not stop_at_atomically... fall through and abort the
4038 case CATCH_RETRY_FRAME:
4039 // IF we find an ATOMICALLY_FRAME then we abort the
4040 // current transaction and propagate the exception. In
4041 // this case (unlike ordinary exceptions) we do not care
4042 // whether the transaction is valid or not because its
4043 // possible validity cannot have caused the exception
4044 // and will not be visible after the abort.
4046 debugBelch("Found atomically block delivering async exception\n"));
4047 StgTRecHeader *trec = tso -> trec;
4048 StgTRecHeader *outer = stmGetEnclosingTRec(trec);
4049 stmAbortTransaction(cap, trec);
4050 tso -> trec = outer;
4057 // move on to the next stack frame
4058 frame += stack_frame_sizeW((StgClosure *)frame);
4061 // if we got here, then we stopped at stop_here
4062 ASSERT(stop_here != NULL);
4065 /* -----------------------------------------------------------------------------
4068 This is used for interruption (^C) and forking, and corresponds to
4069 raising an exception but without letting the thread catch the
4071 -------------------------------------------------------------------------- */
4074 deleteThread (Capability *cap, StgTSO *tso)
4076 if (tso->why_blocked != BlockedOnCCall &&
4077 tso->why_blocked != BlockedOnCCall_NoUnblockExc) {
4078 raiseAsync(cap,tso,NULL);
4082 #ifdef FORKPROCESS_PRIMOP_SUPPORTED
4084 deleteThread_(Capability *cap, StgTSO *tso)
4085 { // for forkProcess only:
4086 // like deleteThread(), but we delete threads in foreign calls, too.
4088 if (tso->why_blocked == BlockedOnCCall ||
4089 tso->why_blocked == BlockedOnCCall_NoUnblockExc) {
4090 unblockOne(cap,tso);
4091 tso->what_next = ThreadKilled;
4093 deleteThread(cap,tso);
4098 /* -----------------------------------------------------------------------------
4099 raiseExceptionHelper
4101 This function is called by the raise# primitve, just so that we can
4102 move some of the tricky bits of raising an exception from C-- into
4103 C. Who knows, it might be a useful re-useable thing here too.
4104 -------------------------------------------------------------------------- */
4107 raiseExceptionHelper (StgRegTable *reg, StgTSO *tso, StgClosure *exception)
4109 Capability *cap = regTableToCapability(reg);
4110 StgThunk *raise_closure = NULL;
4112 StgRetInfoTable *info;
4114 // This closure represents the expression 'raise# E' where E
4115 // is the exception raise. It is used to overwrite all the
4116 // thunks which are currently under evaluataion.
4119 // OLD COMMENT (we don't have MIN_UPD_SIZE now):
4120 // LDV profiling: stg_raise_info has THUNK as its closure
4121 // type. Since a THUNK takes at least MIN_UPD_SIZE words in its
4122 // payload, MIN_UPD_SIZE is more approprate than 1. It seems that
4123 // 1 does not cause any problem unless profiling is performed.
4124 // However, when LDV profiling goes on, we need to linearly scan
4125 // small object pool, where raise_closure is stored, so we should
4126 // use MIN_UPD_SIZE.
4128 // raise_closure = (StgClosure *)RET_STGCALL1(P_,allocate,
4129 // sizeofW(StgClosure)+1);
4133 // Walk up the stack, looking for the catch frame. On the way,
4134 // we update any closures pointed to from update frames with the
4135 // raise closure that we just built.
4139 info = get_ret_itbl((StgClosure *)p);
4140 next = p + stack_frame_sizeW((StgClosure *)p);
4141 switch (info->i.type) {
4144 // Only create raise_closure if we need to.
4145 if (raise_closure == NULL) {
4147 (StgThunk *)allocateLocal(cap,sizeofW(StgThunk)+1);
4148 SET_HDR(raise_closure, &stg_raise_info, CCCS);
4149 raise_closure->payload[0] = exception;
4151 UPD_IND(((StgUpdateFrame *)p)->updatee,(StgClosure *)raise_closure);
4155 case ATOMICALLY_FRAME:
4156 IF_DEBUG(stm, debugBelch("Found ATOMICALLY_FRAME at %p\n", p));
4158 return ATOMICALLY_FRAME;
4164 case CATCH_STM_FRAME:
4165 IF_DEBUG(stm, debugBelch("Found CATCH_STM_FRAME at %p\n", p));
4167 return CATCH_STM_FRAME;
4173 case CATCH_RETRY_FRAME:
4182 /* -----------------------------------------------------------------------------
4183 findRetryFrameHelper
4185 This function is called by the retry# primitive. It traverses the stack
4186 leaving tso->sp referring to the frame which should handle the retry.
4188 This should either be a CATCH_RETRY_FRAME (if the retry# is within an orElse#)
4189 or should be a ATOMICALLY_FRAME (if the retry# reaches the top level).
4191 We skip CATCH_STM_FRAMEs because retries are not considered to be exceptions,
4192 despite the similar implementation.
4194 We should not expect to see CATCH_FRAME or STOP_FRAME because those should
4195 not be created within memory transactions.
4196 -------------------------------------------------------------------------- */
4199 findRetryFrameHelper (StgTSO *tso)
4202 StgRetInfoTable *info;
4206 info = get_ret_itbl((StgClosure *)p);
4207 next = p + stack_frame_sizeW((StgClosure *)p);
4208 switch (info->i.type) {
4210 case ATOMICALLY_FRAME:
4211 IF_DEBUG(stm, debugBelch("Found ATOMICALLY_FRAME at %p during retrry\n", p));
4213 return ATOMICALLY_FRAME;
4215 case CATCH_RETRY_FRAME:
4216 IF_DEBUG(stm, debugBelch("Found CATCH_RETRY_FRAME at %p during retrry\n", p));
4218 return CATCH_RETRY_FRAME;
4220 case CATCH_STM_FRAME:
4222 ASSERT(info->i.type != CATCH_FRAME);
4223 ASSERT(info->i.type != STOP_FRAME);
4230 /* -----------------------------------------------------------------------------
4231 resurrectThreads is called after garbage collection on the list of
4232 threads found to be garbage. Each of these threads will be woken
4233 up and sent a signal: BlockedOnDeadMVar if the thread was blocked
4234 on an MVar, or NonTermination if the thread was blocked on a Black
4237 Locks: assumes we hold *all* the capabilities.
4238 -------------------------------------------------------------------------- */
4241 resurrectThreads (StgTSO *threads)
4246 for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
4247 next = tso->global_link;
4248 tso->global_link = all_threads;
4250 IF_DEBUG(scheduler, sched_belch("resurrecting thread %d", tso->id));
4252 // Wake up the thread on the Capability it was last on
4255 switch (tso->why_blocked) {
4257 case BlockedOnException:
4258 /* Called by GC - sched_mutex lock is currently held. */
4259 raiseAsync(cap, tso,(StgClosure *)BlockedOnDeadMVar_closure);
4261 case BlockedOnBlackHole:
4262 raiseAsync(cap, tso,(StgClosure *)NonTermination_closure);
4265 raiseAsync(cap, tso,(StgClosure *)BlockedIndefinitely_closure);
4268 /* This might happen if the thread was blocked on a black hole
4269 * belonging to a thread that we've just woken up (raiseAsync
4270 * can wake up threads, remember...).
4274 barf("resurrectThreads: thread blocked in a strange way");
4279 /* ----------------------------------------------------------------------------
4280 * Debugging: why is a thread blocked
4281 * [Also provides useful information when debugging threaded programs
4282 * at the Haskell source code level, so enable outside of DEBUG. --sof 7/02]
4283 ------------------------------------------------------------------------- */
4287 printThreadBlockage(StgTSO *tso)
4289 switch (tso->why_blocked) {
4291 debugBelch("is blocked on read from fd %d", (int)(tso->block_info.fd));
4293 case BlockedOnWrite:
4294 debugBelch("is blocked on write to fd %d", (int)(tso->block_info.fd));
4296 #if defined(mingw32_HOST_OS)
4297 case BlockedOnDoProc:
4298 debugBelch("is blocked on proc (request: %ld)", tso->block_info.async_result->reqID);
4301 case BlockedOnDelay:
4302 debugBelch("is blocked until %ld", (long)(tso->block_info.target));
4305 debugBelch("is blocked on an MVar @ %p", tso->block_info.closure);
4307 case BlockedOnException:
4308 debugBelch("is blocked on delivering an exception to thread %d",
4309 tso->block_info.tso->id);
4311 case BlockedOnBlackHole:
4312 debugBelch("is blocked on a black hole");
4315 debugBelch("is not blocked");
4317 #if defined(PARALLEL_HASKELL)
4319 debugBelch("is blocked on global address; local FM_BQ is %p (%s)",
4320 tso->block_info.closure, info_type(tso->block_info.closure));
4322 case BlockedOnGA_NoSend:
4323 debugBelch("is blocked on global address (no send); local FM_BQ is %p (%s)",
4324 tso->block_info.closure, info_type(tso->block_info.closure));
4327 case BlockedOnCCall:
4328 debugBelch("is blocked on an external call");
4330 case BlockedOnCCall_NoUnblockExc:
4331 debugBelch("is blocked on an external call (exceptions were already blocked)");
4334 debugBelch("is blocked on an STM operation");
4337 barf("printThreadBlockage: strange tso->why_blocked: %d for TSO %d (%d)",
4338 tso->why_blocked, tso->id, tso);
4343 printThreadStatus(StgTSO *t)
4345 debugBelch("\tthread %4d @ %p ", t->id, (void *)t);
4347 void *label = lookupThreadLabel(t->id);
4348 if (label) debugBelch("[\"%s\"] ",(char *)label);
4350 if (t->what_next == ThreadRelocated) {
4351 debugBelch("has been relocated...\n");
4353 switch (t->what_next) {
4355 debugBelch("has been killed");
4357 case ThreadComplete:
4358 debugBelch("has completed");
4361 printThreadBlockage(t);
4368 printAllThreads(void)
4375 char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN];
4376 ullong_format_string(TIME_ON_PROC(CurrentProc),
4377 time_string, rtsFalse/*no commas!*/);
4379 debugBelch("all threads at [%s]:\n", time_string);
4380 # elif defined(PARALLEL_HASKELL)
4381 char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN];
4382 ullong_format_string(CURRENT_TIME,
4383 time_string, rtsFalse/*no commas!*/);
4385 debugBelch("all threads at [%s]:\n", time_string);
4387 debugBelch("all threads:\n");
4390 for (i = 0; i < n_capabilities; i++) {
4391 cap = &capabilities[i];
4392 debugBelch("threads on capability %d:\n", cap->no);
4393 for (t = cap->run_queue_hd; t != END_TSO_QUEUE; t = t->link) {
4394 printThreadStatus(t);
4398 debugBelch("other threads:\n");
4399 for (t = all_threads; t != END_TSO_QUEUE; t = next) {
4400 if (t->why_blocked != NotBlocked) {
4401 printThreadStatus(t);
4403 if (t->what_next == ThreadRelocated) {
4406 next = t->global_link;
4413 printThreadQueue(StgTSO *t)
4416 for (; t != END_TSO_QUEUE; t = t->link) {
4417 printThreadStatus(t);
4420 debugBelch("%d threads on queue\n", i);
4424 Print a whole blocking queue attached to node (debugging only).
4426 # if defined(PARALLEL_HASKELL)
4428 print_bq (StgClosure *node)
4430 StgBlockingQueueElement *bqe;
4434 debugBelch("## BQ of closure %p (%s): ",
4435 node, info_type(node));
4437 /* should cover all closures that may have a blocking queue */
4438 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
4439 get_itbl(node)->type == FETCH_ME_BQ ||
4440 get_itbl(node)->type == RBH ||
4441 get_itbl(node)->type == MVAR);
4443 ASSERT(node!=(StgClosure*)NULL); // sanity check
4445 print_bqe(((StgBlockingQueue*)node)->blocking_queue);
4449 Print a whole blocking queue starting with the element bqe.
4452 print_bqe (StgBlockingQueueElement *bqe)
4457 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
4459 for (end = (bqe==END_BQ_QUEUE);
4460 !end; // iterate until bqe points to a CONSTR
4461 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE),
4462 bqe = end ? END_BQ_QUEUE : bqe->link) {
4463 ASSERT(bqe != END_BQ_QUEUE); // sanity check
4464 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
4465 /* types of closures that may appear in a blocking queue */
4466 ASSERT(get_itbl(bqe)->type == TSO ||
4467 get_itbl(bqe)->type == BLOCKED_FETCH ||
4468 get_itbl(bqe)->type == CONSTR);
4469 /* only BQs of an RBH end with an RBH_Save closure */
4470 //ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
4472 switch (get_itbl(bqe)->type) {
4474 debugBelch(" TSO %u (%x),",
4475 ((StgTSO *)bqe)->id, ((StgTSO *)bqe));
4478 debugBelch(" BF (node=%p, ga=((%x, %d, %x)),",
4479 ((StgBlockedFetch *)bqe)->node,
4480 ((StgBlockedFetch *)bqe)->ga.payload.gc.gtid,
4481 ((StgBlockedFetch *)bqe)->ga.payload.gc.slot,
4482 ((StgBlockedFetch *)bqe)->ga.weight);
4485 debugBelch(" %s (IP %p),",
4486 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
4487 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
4488 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
4489 "RBH_Save_?"), get_itbl(bqe));
4492 barf("Unexpected closure type %s in blocking queue", // of %p (%s)",
4493 info_type((StgClosure *)bqe)); // , node, info_type(node));
4499 # elif defined(GRAN)
4501 print_bq (StgClosure *node)
4503 StgBlockingQueueElement *bqe;
4504 PEs node_loc, tso_loc;
4507 /* should cover all closures that may have a blocking queue */
4508 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
4509 get_itbl(node)->type == FETCH_ME_BQ ||
4510 get_itbl(node)->type == RBH);
4512 ASSERT(node!=(StgClosure*)NULL); // sanity check
4513 node_loc = where_is(node);
4515 debugBelch("## BQ of closure %p (%s) on [PE %d]: ",
4516 node, info_type(node), node_loc);
4519 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
4521 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
4522 !end; // iterate until bqe points to a CONSTR
4523 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
4524 ASSERT(bqe != END_BQ_QUEUE); // sanity check
4525 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
4526 /* types of closures that may appear in a blocking queue */
4527 ASSERT(get_itbl(bqe)->type == TSO ||
4528 get_itbl(bqe)->type == CONSTR);
4529 /* only BQs of an RBH end with an RBH_Save closure */
4530 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
4532 tso_loc = where_is((StgClosure *)bqe);
4533 switch (get_itbl(bqe)->type) {
4535 debugBelch(" TSO %d (%p) on [PE %d],",
4536 ((StgTSO *)bqe)->id, (StgTSO *)bqe, tso_loc);
4539 debugBelch(" %s (IP %p),",
4540 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
4541 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
4542 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
4543 "RBH_Save_?"), get_itbl(bqe));
4546 barf("Unexpected closure type %s in blocking queue of %p (%s)",
4547 info_type((StgClosure *)bqe), node, info_type(node));
4555 #if defined(PARALLEL_HASKELL)
4562 for (i=0, tso=run_queue_hd;
4563 tso != END_TSO_QUEUE;
4564 i++, tso=tso->link) {
4573 sched_belch(char *s, ...)
4578 debugBelch("sched (task %p): ", (void *)(unsigned long)(unsigned int)osThreadId());
4579 #elif defined(PARALLEL_HASKELL)
4582 debugBelch("sched: ");