1 /* ---------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2004
7 * Different GHC ways use this scheduler quite differently (see comments below)
8 * Here is the global picture:
10 * WAY Name CPP flag What's it for
11 * --------------------------------------
12 * mp GUM PARALLEL_HASKELL Parallel execution on a distrib. memory machine
13 * s SMP SMP Parallel execution on a shared memory machine
14 * mg GranSim GRAN Simulation of parallel execution
15 * md GUM/GdH DIST Distributed execution (based on GUM)
17 * --------------------------------------------------------------------------*/
20 * Version with support for distributed memory parallelism aka GUM (WAY=mp):
22 The main scheduling loop in GUM iterates until a finish message is received.
23 In that case a global flag @receivedFinish@ is set and this instance of
24 the RTS shuts down. See ghc/rts/parallel/HLComms.c:processMessages()
25 for the handling of incoming messages, such as PP_FINISH.
26 Note that in the parallel case we have a system manager that coordinates
27 different PEs, each of which are running one instance of the RTS.
28 See ghc/rts/parallel/SysMan.c for the main routine of the parallel program.
29 From this routine processes executing ghc/rts/Main.c are spawned. -- HWL
31 * Version with support for simulating parallel execution aka GranSim (WAY=mg):
33 The main scheduling code in GranSim is quite different from that in std
34 (concurrent) Haskell: while concurrent Haskell just iterates over the
35 threads in the runnable queue, GranSim is event driven, i.e. it iterates
36 over the events in the global event queue. -- HWL
39 #include "PosixSource.h"
44 #include "BlockAlloc.h"
45 #include "OSThreads.h"
49 #define COMPILING_SCHEDULER
51 #include "StgMiscClosures.h"
52 #include "Interpreter.h"
53 #include "Exception.h"
61 #include "ThreadLabels.h"
62 #include "LdvProfile.h"
65 #include "Proftimer.h"
68 #if defined(GRAN) || defined(PARALLEL_HASKELL)
69 # include "GranSimRts.h"
71 # include "ParallelRts.h"
72 # include "Parallel.h"
73 # include "ParallelDebug.h"
78 #include "Capability.h"
81 #ifdef HAVE_SYS_TYPES_H
82 #include <sys/types.h>
96 // Turn off inlining when debugging - it obfuscates things
99 # define STATIC_INLINE static
103 #define USED_IN_THREADED_RTS
105 #define USED_IN_THREADED_RTS STG_UNUSED
108 #ifdef RTS_SUPPORTS_THREADS
109 #define USED_WHEN_RTS_SUPPORTS_THREADS
111 #define USED_WHEN_RTS_SUPPORTS_THREADS STG_UNUSED
114 /* Main thread queue.
115 * Locks required: sched_mutex.
117 StgMainThread *main_threads = NULL;
121 StgTSO* ActiveTSO = NULL; /* for assigning system costs; GranSim-Light only */
122 /* rtsTime TimeOfNextEvent, EndOfTimeSlice; now in GranSim.c */
125 In GranSim we have a runnable and a blocked queue for each processor.
126 In order to minimise code changes new arrays run_queue_hds/tls
127 are created. run_queue_hd is then a short cut (macro) for
128 run_queue_hds[CurrentProc] (see GranSim.h).
131 StgTSO *run_queue_hds[MAX_PROC], *run_queue_tls[MAX_PROC];
132 StgTSO *blocked_queue_hds[MAX_PROC], *blocked_queue_tls[MAX_PROC];
133 StgTSO *ccalling_threadss[MAX_PROC];
134 /* We use the same global list of threads (all_threads) in GranSim as in
135 the std RTS (i.e. we are cheating). However, we don't use this list in
136 the GranSim specific code at the moment (so we are only potentially
142 * Locks required: sched_mutex.
144 StgTSO *run_queue_hd = NULL;
145 StgTSO *run_queue_tl = NULL;
146 StgTSO *blocked_queue_hd = NULL;
147 StgTSO *blocked_queue_tl = NULL;
148 StgTSO *blackhole_queue = NULL;
149 StgTSO *sleeping_queue = NULL; /* perhaps replace with a hash table? */
153 /* The blackhole_queue should be checked for threads to wake up. See
154 * Schedule.h for more thorough comment.
156 rtsBool blackholes_need_checking = rtsFalse;
158 /* Linked list of all threads.
159 * Used for detecting garbage collected threads.
161 StgTSO *all_threads = NULL;
163 /* When a thread performs a safe C call (_ccall_GC, using old
164 * terminology), it gets put on the suspended_ccalling_threads
165 * list. Used by the garbage collector.
167 static StgTSO *suspended_ccalling_threads;
169 /* KH: The following two flags are shared memory locations. There is no need
170 to lock them, since they are only unset at the end of a scheduler
174 /* flag set by signal handler to precipitate a context switch */
175 int context_switch = 0;
177 /* flag that tracks whether we have done any execution in this time slice. */
178 nat recent_activity = ACTIVITY_YES;
180 /* if this flag is set as well, give up execution */
181 rtsBool interrupted = rtsFalse;
183 /* Next thread ID to allocate.
184 * Locks required: thread_id_mutex
186 static StgThreadID next_thread_id = 1;
189 * Pointers to the state of the current thread.
190 * Rule of thumb: if CurrentTSO != NULL, then we're running a Haskell
191 * thread. If CurrentTSO == NULL, then we're at the scheduler level.
194 /* The smallest stack size that makes any sense is:
195 * RESERVED_STACK_WORDS (so we can get back from the stack overflow)
196 * + sizeofW(StgStopFrame) (the stg_stop_thread_info frame)
197 * + 1 (the closure to enter)
199 * + 1 (spare slot req'd by stg_ap_v_ret)
201 * A thread with this stack will bomb immediately with a stack
202 * overflow, which will increase its stack size.
205 #define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 3)
212 /* This is used in `TSO.h' and gcc 2.96 insists that this variable actually
213 * exists - earlier gccs apparently didn't.
219 * Set to TRUE when entering a shutdown state (via shutdownHaskellAndExit()) --
220 * in an MT setting, needed to signal that a worker thread shouldn't hang around
221 * in the scheduler when it is out of work.
223 static rtsBool shutting_down_scheduler = rtsFalse;
225 #if defined(RTS_SUPPORTS_THREADS)
226 /* ToDo: carefully document the invariants that go together
227 * with these synchronisation objects.
229 Mutex sched_mutex = INIT_MUTEX_VAR;
230 Mutex term_mutex = INIT_MUTEX_VAR;
232 #endif /* RTS_SUPPORTS_THREADS */
234 #if defined(PARALLEL_HASKELL)
236 rtsTime TimeOfLastYield;
237 rtsBool emitSchedule = rtsTrue;
241 static char *whatNext_strs[] = {
251 /* -----------------------------------------------------------------------------
252 * static function prototypes
253 * -------------------------------------------------------------------------- */
255 #if defined(RTS_SUPPORTS_THREADS)
256 static void taskStart(void);
259 static void schedule( StgMainThread *mainThread USED_WHEN_RTS_SUPPORTS_THREADS,
260 Capability *initialCapability );
263 // These function all encapsulate parts of the scheduler loop, and are
264 // abstracted only to make the structure and control flow of the
265 // scheduler clearer.
267 static void schedulePreLoop(void);
268 static void scheduleStartSignalHandlers(void);
269 static void scheduleCheckBlockedThreads(void);
270 static void scheduleCheckBlackHoles(void);
271 static void scheduleDetectDeadlock(void);
273 static StgTSO *scheduleProcessEvent(rtsEvent *event);
275 #if defined(PARALLEL_HASKELL)
276 static StgTSO *scheduleSendPendingMessages(void);
277 static void scheduleActivateSpark(void);
278 static rtsBool scheduleGetRemoteWork(rtsBool *receivedFinish);
280 #if defined(PAR) || defined(GRAN)
281 static void scheduleGranParReport(void);
283 static void schedulePostRunThread(void);
284 static rtsBool scheduleHandleHeapOverflow( Capability *cap, StgTSO *t );
285 static void scheduleHandleStackOverflow( StgTSO *t);
286 static rtsBool scheduleHandleYield( StgTSO *t, nat prev_what_next );
287 static void scheduleHandleThreadBlocked( StgTSO *t );
288 static rtsBool scheduleHandleThreadFinished( StgMainThread *mainThread,
289 Capability *cap, StgTSO *t );
290 static rtsBool scheduleDoHeapProfile(rtsBool ready_to_gc);
291 static void scheduleDoGC(rtsBool force_major);
293 static void unblockThread(StgTSO *tso);
294 static rtsBool checkBlackHoles(void);
295 static SchedulerStatus waitThread_(/*out*/StgMainThread* m,
296 Capability *initialCapability
298 static void scheduleThread_ (StgTSO* tso);
299 static void AllRoots(evac_fn evac);
301 static StgTSO *threadStackOverflow(StgTSO *tso);
303 static void raiseAsync_(StgTSO *tso, StgClosure *exception,
304 rtsBool stop_at_atomically);
306 static void printThreadBlockage(StgTSO *tso);
307 static void printThreadStatus(StgTSO *tso);
308 void printThreadQueue(StgTSO *tso);
310 #if defined(PARALLEL_HASKELL)
311 StgTSO * createSparkThread(rtsSpark spark);
312 StgTSO * activateSpark (rtsSpark spark);
315 /* ----------------------------------------------------------------------------
317 * ------------------------------------------------------------------------- */
319 #if defined(RTS_SUPPORTS_THREADS)
320 static nat startingWorkerThread = 0;
325 ACQUIRE_LOCK(&sched_mutex);
326 startingWorkerThread--;
329 RELEASE_LOCK(&sched_mutex);
333 startSchedulerTaskIfNecessary(void)
335 if ( !EMPTY_RUN_QUEUE()
336 && !shutting_down_scheduler // not if we're shutting down
337 && startingWorkerThread==0)
339 // we don't want to start another worker thread
340 // just because the last one hasn't yet reached the
341 // "waiting for capability" state
342 startingWorkerThread++;
343 if (!maybeStartNewWorker(taskStart)) {
344 startingWorkerThread--;
350 /* -----------------------------------------------------------------------------
351 * Putting a thread on the run queue: different scheduling policies
352 * -------------------------------------------------------------------------- */
355 addToRunQueue( StgTSO *t )
357 #if defined(PARALLEL_HASKELL)
358 if (RtsFlags.ParFlags.doFairScheduling) {
359 // this does round-robin scheduling; good for concurrency
360 APPEND_TO_RUN_QUEUE(t);
362 // this does unfair scheduling; good for parallelism
363 PUSH_ON_RUN_QUEUE(t);
366 // this does round-robin scheduling; good for concurrency
367 APPEND_TO_RUN_QUEUE(t);
371 /* ---------------------------------------------------------------------------
372 Main scheduling loop.
374 We use round-robin scheduling, each thread returning to the
375 scheduler loop when one of these conditions is detected:
378 * timer expires (thread yields)
383 Locking notes: we acquire the scheduler lock once at the beginning
384 of the scheduler loop, and release it when
386 * running a thread, or
387 * waiting for work, or
388 * waiting for a GC to complete.
391 In a GranSim setup this loop iterates over the global event queue.
392 This revolves around the global event queue, which determines what
393 to do next. Therefore, it's more complicated than either the
394 concurrent or the parallel (GUM) setup.
397 GUM iterates over incoming messages.
398 It starts with nothing to do (thus CurrentTSO == END_TSO_QUEUE),
399 and sends out a fish whenever it has nothing to do; in-between
400 doing the actual reductions (shared code below) it processes the
401 incoming messages and deals with delayed operations
402 (see PendingFetches).
403 This is not the ugliest code you could imagine, but it's bloody close.
405 ------------------------------------------------------------------------ */
408 schedule( StgMainThread *mainThread USED_WHEN_RTS_SUPPORTS_THREADS,
409 Capability *initialCapability )
413 StgThreadReturnCode ret;
416 #elif defined(PARALLEL_HASKELL)
419 rtsBool receivedFinish = rtsFalse;
421 nat tp_size, sp_size; // stats only
427 // Pre-condition: sched_mutex is held.
428 // We might have a capability, passed in as initialCapability.
429 cap = initialCapability;
431 #if !defined(RTS_SUPPORTS_THREADS)
432 // simply initialise it in the non-threaded case
433 grabCapability(&cap);
437 sched_belch("### NEW SCHEDULER LOOP (main thr: %p, cap: %p)",
438 mainThread, initialCapability);
443 // -----------------------------------------------------------
444 // Scheduler loop starts here:
446 #if defined(PARALLEL_HASKELL)
447 #define TERMINATION_CONDITION (!receivedFinish)
449 #define TERMINATION_CONDITION ((event = get_next_event()) != (rtsEvent*)NULL)
451 #define TERMINATION_CONDITION rtsTrue
454 while (TERMINATION_CONDITION) {
457 /* Choose the processor with the next event */
458 CurrentProc = event->proc;
459 CurrentTSO = event->tso;
462 #if defined(RTS_SUPPORTS_THREADS)
463 // Yield the capability to higher-priority tasks if necessary.
466 yieldCapability(&cap,
467 mainThread ? &mainThread->bound_thread_cond : NULL );
470 // If we do not currently hold a capability, we wait for one
473 waitForCapability(&sched_mutex, &cap,
474 mainThread ? &mainThread->bound_thread_cond : NULL);
477 // We now have a capability...
480 #if 0 /* extra sanity checking */
483 for (m = main_threads; m != NULL; m = m->link) {
484 ASSERT(get_itbl(m->tso)->type == TSO);
489 // Check whether we have re-entered the RTS from Haskell without
490 // going via suspendThread()/resumeThread (i.e. a 'safe' foreign
492 if (cap->r.rInHaskell) {
493 errorBelch("schedule: re-entered unsafely.\n"
494 " Perhaps a 'foreign import unsafe' should be 'safe'?");
499 // Test for interruption. If interrupted==rtsTrue, then either
500 // we received a keyboard interrupt (^C), or the scheduler is
501 // trying to shut down all the tasks (shutting_down_scheduler) in
505 if (shutting_down_scheduler) {
506 IF_DEBUG(scheduler, sched_belch("shutting down"));
507 releaseCapability(cap);
509 mainThread->stat = Interrupted;
510 mainThread->ret = NULL;
514 IF_DEBUG(scheduler, sched_belch("interrupted"));
519 #if defined(not_yet) && defined(SMP)
521 // Top up the run queue from our spark pool. We try to make the
522 // number of threads in the run queue equal to the number of
523 // free capabilities.
527 if (EMPTY_RUN_QUEUE()) {
528 spark = findSpark(rtsFalse);
530 break; /* no more sparks in the pool */
532 createSparkThread(spark);
534 sched_belch("==^^ turning spark of closure %p into a thread",
535 (StgClosure *)spark));
541 scheduleStartSignalHandlers();
543 // Only check the black holes here if we've nothing else to do.
544 // During normal execution, the black hole list only gets checked
545 // at GC time, to avoid repeatedly traversing this possibly long
546 // list each time around the scheduler.
547 if (EMPTY_RUN_QUEUE()) { scheduleCheckBlackHoles(); }
549 scheduleCheckBlockedThreads();
551 scheduleDetectDeadlock();
553 // Normally, the only way we can get here with no threads to
554 // run is if a keyboard interrupt received during
555 // scheduleCheckBlockedThreads() or scheduleDetectDeadlock().
556 // Additionally, it is not fatal for the
557 // threaded RTS to reach here with no threads to run.
559 // win32: might be here due to awaitEvent() being abandoned
560 // as a result of a console event having been delivered.
561 if ( EMPTY_RUN_QUEUE() ) {
562 #if !defined(RTS_SUPPORTS_THREADS) && !defined(mingw32_HOST_OS)
565 continue; // nothing to do
568 #if defined(PARALLEL_HASKELL)
569 scheduleSendPendingMessages();
570 if (EMPTY_RUN_QUEUE() && scheduleActivateSpark())
574 ASSERT(next_fish_to_send_at==0); // i.e. no delayed fishes left!
577 /* If we still have no work we need to send a FISH to get a spark
579 if (EMPTY_RUN_QUEUE()) {
580 if (!scheduleGetRemoteWork(&receivedFinish)) continue;
581 ASSERT(rtsFalse); // should not happen at the moment
583 // from here: non-empty run queue.
584 // TODO: merge above case with this, only one call processMessages() !
585 if (PacketsWaiting()) { /* process incoming messages, if
586 any pending... only in else
587 because getRemoteWork waits for
589 receivedFinish = processMessages();
594 scheduleProcessEvent(event);
598 // Get a thread to run
600 ASSERT(run_queue_hd != END_TSO_QUEUE);
603 #if defined(GRAN) || defined(PAR)
604 scheduleGranParReport(); // some kind of debuging output
606 // Sanity check the thread we're about to run. This can be
607 // expensive if there is lots of thread switching going on...
608 IF_DEBUG(sanity,checkTSO(t));
611 #if defined(RTS_SUPPORTS_THREADS)
612 // Check whether we can run this thread in the current task.
613 // If not, we have to pass our capability to the right task.
615 StgMainThread *m = t->main;
622 sched_belch("### Running thread %d in bound thread", t->id));
623 // yes, the Haskell thread is bound to the current native thread
628 sched_belch("### thread %d bound to another OS thread", t->id));
629 // no, bound to a different Haskell thread: pass to that thread
630 PUSH_ON_RUN_QUEUE(t);
636 if(mainThread != NULL)
637 // The thread we want to run is unbound.
640 sched_belch("### this OS thread cannot run thread %d", t->id));
641 // no, the current native thread is bound to a different
642 // Haskell thread, so pass it to any worker thread
643 PUSH_ON_RUN_QUEUE(t);
650 cap->r.rCurrentTSO = t;
652 /* context switches are now initiated by the timer signal, unless
653 * the user specified "context switch as often as possible", with
656 if ((RtsFlags.ConcFlags.ctxtSwitchTicks == 0
657 && (run_queue_hd != END_TSO_QUEUE
658 || blocked_queue_hd != END_TSO_QUEUE
659 || sleeping_queue != END_TSO_QUEUE)))
664 RELEASE_LOCK(&sched_mutex);
666 IF_DEBUG(scheduler, sched_belch("-->> running thread %ld %s ...",
667 (long)t->id, whatNext_strs[t->what_next]));
669 #if defined(PROFILING)
670 startHeapProfTimer();
673 // ----------------------------------------------------------------------
674 // Run the current thread
676 prev_what_next = t->what_next;
678 errno = t->saved_errno;
679 cap->r.rInHaskell = rtsTrue;
681 recent_activity = ACTIVITY_YES;
683 switch (prev_what_next) {
687 /* Thread already finished, return to scheduler. */
688 ret = ThreadFinished;
692 ret = StgRun((StgFunPtr) stg_returnToStackTop, &cap->r);
695 case ThreadInterpret:
696 ret = interpretBCO(cap);
700 barf("schedule: invalid what_next field");
704 // in SMP mode, we might return with a different capability than
705 // we started with, if the Haskell thread made a foreign call. So
706 // let's find out what our current Capability is:
707 cap = myCapability();
710 // We have run some Haskell code: there might be blackhole-blocked
711 // threads to wake up now.
712 if ( blackhole_queue != END_TSO_QUEUE ) {
713 blackholes_need_checking = rtsTrue;
716 cap->r.rInHaskell = rtsFalse;
718 // The TSO might have moved, eg. if it re-entered the RTS and a GC
719 // happened. So find the new location:
720 t = cap->r.rCurrentTSO;
722 // And save the current errno in this thread.
723 t->saved_errno = errno;
725 // ----------------------------------------------------------------------
727 /* Costs for the scheduler are assigned to CCS_SYSTEM */
728 #if defined(PROFILING)
733 ACQUIRE_LOCK(&sched_mutex);
735 #if defined(RTS_SUPPORTS_THREADS)
736 IF_DEBUG(scheduler,debugBelch("sched (task %p): ", osThreadId()););
737 #elif !defined(GRAN) && !defined(PARALLEL_HASKELL)
738 IF_DEBUG(scheduler,debugBelch("sched: "););
741 schedulePostRunThread();
743 ready_to_gc = rtsFalse;
747 ready_to_gc = scheduleHandleHeapOverflow(cap,t);
751 scheduleHandleStackOverflow(t);
755 if (scheduleHandleYield(t, prev_what_next)) {
756 // shortcut for switching between compiler/interpreter:
762 scheduleHandleThreadBlocked(t);
766 if (scheduleHandleThreadFinished(mainThread, cap, t)) return;;
770 barf("schedule: invalid thread return code %d", (int)ret);
773 if (scheduleDoHeapProfile(ready_to_gc)) { ready_to_gc = rtsFalse; }
774 if (ready_to_gc) { scheduleDoGC(rtsFalse); }
775 } /* end of while() */
777 IF_PAR_DEBUG(verbose,
778 debugBelch("== Leaving schedule() after having received Finish\n"));
781 /* ----------------------------------------------------------------------------
782 * Setting up the scheduler loop
783 * ASSUMES: sched_mutex
784 * ------------------------------------------------------------------------- */
787 schedulePreLoop(void)
790 /* set up first event to get things going */
791 /* ToDo: assign costs for system setup and init MainTSO ! */
792 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
794 CurrentTSO, (StgClosure*)NULL, (rtsSpark*)NULL);
797 debugBelch("GRAN: Init CurrentTSO (in schedule) = %p\n",
799 G_TSO(CurrentTSO, 5));
801 if (RtsFlags.GranFlags.Light) {
802 /* Save current time; GranSim Light only */
803 CurrentTSO->gran.clock = CurrentTime[CurrentProc];
808 /* ----------------------------------------------------------------------------
809 * Start any pending signal handlers
810 * ASSUMES: sched_mutex
811 * ------------------------------------------------------------------------- */
814 scheduleStartSignalHandlers(void)
816 #if defined(RTS_USER_SIGNALS) && !defined(RTS_SUPPORTS_THREADS)
817 if (signals_pending()) {
818 RELEASE_LOCK(&sched_mutex); /* ToDo: kill */
819 startSignalHandlers();
820 ACQUIRE_LOCK(&sched_mutex);
825 /* ----------------------------------------------------------------------------
826 * Check for blocked threads that can be woken up.
827 * ASSUMES: sched_mutex
828 * ------------------------------------------------------------------------- */
831 scheduleCheckBlockedThreads(void)
834 // Check whether any waiting threads need to be woken up. If the
835 // run queue is empty, and there are no other tasks running, we
836 // can wait indefinitely for something to happen.
838 if ( !EMPTY_QUEUE(blocked_queue_hd) || !EMPTY_QUEUE(sleeping_queue) )
840 #if defined(RTS_SUPPORTS_THREADS)
841 // We shouldn't be here...
842 barf("schedule: awaitEvent() in threaded RTS");
844 awaitEvent( EMPTY_RUN_QUEUE() );
849 /* ----------------------------------------------------------------------------
850 * Check for threads blocked on BLACKHOLEs that can be woken up
851 * ASSUMES: sched_mutex
852 * ------------------------------------------------------------------------- */
854 scheduleCheckBlackHoles( void )
856 if ( blackholes_need_checking )
859 blackholes_need_checking = rtsFalse;
863 /* ----------------------------------------------------------------------------
864 * Detect deadlock conditions and attempt to resolve them.
865 * ASSUMES: sched_mutex
866 * ------------------------------------------------------------------------- */
869 scheduleDetectDeadlock()
872 #if defined(PARALLEL_HASKELL)
873 // ToDo: add deadlock detection in GUM (similar to SMP) -- HWL
878 * Detect deadlock: when we have no threads to run, there are no
879 * threads blocked, waiting for I/O, or sleeping, and all the
880 * other tasks are waiting for work, we must have a deadlock of
883 if ( EMPTY_THREAD_QUEUES() )
885 #if defined(RTS_SUPPORTS_THREADS)
887 * In the threaded RTS, we only check for deadlock if there
888 * has been no activity in a complete timeslice. This means
889 * we won't eagerly start a full GC just because we don't have
890 * any threads to run currently.
892 if (recent_activity != ACTIVITY_INACTIVE) return;
895 IF_DEBUG(scheduler, sched_belch("deadlocked, forcing major GC..."));
897 // Garbage collection can release some new threads due to
898 // either (a) finalizers or (b) threads resurrected because
899 // they are unreachable and will therefore be sent an
900 // exception. Any threads thus released will be immediately
903 scheduleDoGC( rtsTrue/*force major GC*/ );
904 recent_activity = ACTIVITY_DONE_GC;
905 if ( !EMPTY_RUN_QUEUE() ) return;
907 #if defined(RTS_USER_SIGNALS) && !defined(RTS_SUPPORTS_THREADS)
908 /* If we have user-installed signal handlers, then wait
909 * for signals to arrive rather then bombing out with a
912 if ( anyUserHandlers() ) {
914 sched_belch("still deadlocked, waiting for signals..."));
918 if (signals_pending()) {
919 RELEASE_LOCK(&sched_mutex);
920 startSignalHandlers();
921 ACQUIRE_LOCK(&sched_mutex);
924 // either we have threads to run, or we were interrupted:
925 ASSERT(!EMPTY_RUN_QUEUE() || interrupted);
929 #if !defined(RTS_SUPPORTS_THREADS)
930 /* Probably a real deadlock. Send the current main thread the
931 * Deadlock exception (or in the SMP build, send *all* main
932 * threads the deadlock exception, since none of them can make
938 switch (m->tso->why_blocked) {
940 case BlockedOnBlackHole:
941 case BlockedOnException:
943 raiseAsync(m->tso, (StgClosure *)NonTermination_closure);
946 barf("deadlock: main thread blocked in a strange way");
953 /* ----------------------------------------------------------------------------
954 * Process an event (GRAN only)
955 * ------------------------------------------------------------------------- */
959 scheduleProcessEvent(rtsEvent *event)
963 if (RtsFlags.GranFlags.Light)
964 GranSimLight_enter_system(event, &ActiveTSO); // adjust ActiveTSO etc
966 /* adjust time based on time-stamp */
967 if (event->time > CurrentTime[CurrentProc] &&
968 event->evttype != ContinueThread)
969 CurrentTime[CurrentProc] = event->time;
971 /* Deal with the idle PEs (may issue FindWork or MoveSpark events) */
972 if (!RtsFlags.GranFlags.Light)
975 IF_DEBUG(gran, debugBelch("GRAN: switch by event-type\n"));
977 /* main event dispatcher in GranSim */
978 switch (event->evttype) {
979 /* Should just be continuing execution */
981 IF_DEBUG(gran, debugBelch("GRAN: doing ContinueThread\n"));
982 /* ToDo: check assertion
983 ASSERT(run_queue_hd != (StgTSO*)NULL &&
984 run_queue_hd != END_TSO_QUEUE);
986 /* Ignore ContinueThreads for fetching threads (if synchr comm) */
987 if (!RtsFlags.GranFlags.DoAsyncFetch &&
988 procStatus[CurrentProc]==Fetching) {
989 debugBelch("ghuH: Spurious ContinueThread while Fetching ignored; TSO %d (%p) [PE %d]\n",
990 CurrentTSO->id, CurrentTSO, CurrentProc);
993 /* Ignore ContinueThreads for completed threads */
994 if (CurrentTSO->what_next == ThreadComplete) {
995 debugBelch("ghuH: found a ContinueThread event for completed thread %d (%p) [PE %d] (ignoring ContinueThread)\n",
996 CurrentTSO->id, CurrentTSO, CurrentProc);
999 /* Ignore ContinueThreads for threads that are being migrated */
1000 if (PROCS(CurrentTSO)==Nowhere) {
1001 debugBelch("ghuH: trying to run the migrating TSO %d (%p) [PE %d] (ignoring ContinueThread)\n",
1002 CurrentTSO->id, CurrentTSO, CurrentProc);
1005 /* The thread should be at the beginning of the run queue */
1006 if (CurrentTSO!=run_queue_hds[CurrentProc]) {
1007 debugBelch("ghuH: TSO %d (%p) [PE %d] is not at the start of the run_queue when doing a ContinueThread\n",
1008 CurrentTSO->id, CurrentTSO, CurrentProc);
1009 break; // run the thread anyway
1012 new_event(proc, proc, CurrentTime[proc],
1014 (StgTSO*)NULL, (StgClosure*)NULL, (rtsSpark*)NULL);
1016 */ /* Catches superfluous CONTINUEs -- should be unnecessary */
1017 break; // now actually run the thread; DaH Qu'vam yImuHbej
1020 do_the_fetchnode(event);
1021 goto next_thread; /* handle next event in event queue */
1024 do_the_globalblock(event);
1025 goto next_thread; /* handle next event in event queue */
1028 do_the_fetchreply(event);
1029 goto next_thread; /* handle next event in event queue */
1031 case UnblockThread: /* Move from the blocked queue to the tail of */
1032 do_the_unblock(event);
1033 goto next_thread; /* handle next event in event queue */
1035 case ResumeThread: /* Move from the blocked queue to the tail of */
1036 /* the runnable queue ( i.e. Qu' SImqa'lu') */
1037 event->tso->gran.blocktime +=
1038 CurrentTime[CurrentProc] - event->tso->gran.blockedat;
1039 do_the_startthread(event);
1040 goto next_thread; /* handle next event in event queue */
1043 do_the_startthread(event);
1044 goto next_thread; /* handle next event in event queue */
1047 do_the_movethread(event);
1048 goto next_thread; /* handle next event in event queue */
1051 do_the_movespark(event);
1052 goto next_thread; /* handle next event in event queue */
1055 do_the_findwork(event);
1056 goto next_thread; /* handle next event in event queue */
1059 barf("Illegal event type %u\n", event->evttype);
1062 /* This point was scheduler_loop in the old RTS */
1064 IF_DEBUG(gran, debugBelch("GRAN: after main switch\n"));
1066 TimeOfLastEvent = CurrentTime[CurrentProc];
1067 TimeOfNextEvent = get_time_of_next_event();
1068 IgnoreEvents=(TimeOfNextEvent==0); // HWL HACK
1069 // CurrentTSO = ThreadQueueHd;
1071 IF_DEBUG(gran, debugBelch("GRAN: time of next event is: %ld\n",
1074 if (RtsFlags.GranFlags.Light)
1075 GranSimLight_leave_system(event, &ActiveTSO);
1077 EndOfTimeSlice = CurrentTime[CurrentProc]+RtsFlags.GranFlags.time_slice;
1080 debugBelch("GRAN: end of time-slice is %#lx\n", EndOfTimeSlice));
1082 /* in a GranSim setup the TSO stays on the run queue */
1084 /* Take a thread from the run queue. */
1085 POP_RUN_QUEUE(t); // take_off_run_queue(t);
1088 debugBelch("GRAN: About to run current thread, which is\n");
1091 context_switch = 0; // turned on via GranYield, checking events and time slice
1094 DumpGranEvent(GR_SCHEDULE, t));
1096 procStatus[CurrentProc] = Busy;
1100 /* ----------------------------------------------------------------------------
1101 * Send pending messages (PARALLEL_HASKELL only)
1102 * ------------------------------------------------------------------------- */
1104 #if defined(PARALLEL_HASKELL)
1106 scheduleSendPendingMessages(void)
1112 # if defined(PAR) // global Mem.Mgmt., omit for now
1113 if (PendingFetches != END_BF_QUEUE) {
1118 if (RtsFlags.ParFlags.BufferTime) {
1119 // if we use message buffering, we must send away all message
1120 // packets which have become too old...
1126 /* ----------------------------------------------------------------------------
1127 * Activate spark threads (PARALLEL_HASKELL only)
1128 * ------------------------------------------------------------------------- */
1130 #if defined(PARALLEL_HASKELL)
1132 scheduleActivateSpark(void)
1135 ASSERT(EMPTY_RUN_QUEUE());
1136 /* We get here if the run queue is empty and want some work.
1137 We try to turn a spark into a thread, and add it to the run queue,
1138 from where it will be picked up in the next iteration of the scheduler
1142 /* :-[ no local threads => look out for local sparks */
1143 /* the spark pool for the current PE */
1144 pool = &(cap.r.rSparks); // JB: cap = (old) MainCap
1145 if (advisory_thread_count < RtsFlags.ParFlags.maxThreads &&
1146 pool->hd < pool->tl) {
1148 * ToDo: add GC code check that we really have enough heap afterwards!!
1150 * If we're here (no runnable threads) and we have pending
1151 * sparks, we must have a space problem. Get enough space
1152 * to turn one of those pending sparks into a
1156 spark = findSpark(rtsFalse); /* get a spark */
1157 if (spark != (rtsSpark) NULL) {
1158 tso = createThreadFromSpark(spark); /* turn the spark into a thread */
1159 IF_PAR_DEBUG(fish, // schedule,
1160 debugBelch("==== schedule: Created TSO %d (%p); %d threads active\n",
1161 tso->id, tso, advisory_thread_count));
1163 if (tso==END_TSO_QUEUE) { /* failed to activate spark->back to loop */
1164 IF_PAR_DEBUG(fish, // schedule,
1165 debugBelch("==^^ failed to create thread from spark @ %lx\n",
1167 return rtsFalse; /* failed to generate a thread */
1168 } /* otherwise fall through & pick-up new tso */
1170 IF_PAR_DEBUG(fish, // schedule,
1171 debugBelch("==^^ no local sparks (spark pool contains only NFs: %d)\n",
1172 spark_queue_len(pool)));
1173 return rtsFalse; /* failed to generate a thread */
1175 return rtsTrue; /* success in generating a thread */
1176 } else { /* no more threads permitted or pool empty */
1177 return rtsFalse; /* failed to generateThread */
1180 tso = NULL; // avoid compiler warning only
1181 return rtsFalse; /* dummy in non-PAR setup */
1184 #endif // PARALLEL_HASKELL
1186 /* ----------------------------------------------------------------------------
1187 * Get work from a remote node (PARALLEL_HASKELL only)
1188 * ------------------------------------------------------------------------- */
1190 #if defined(PARALLEL_HASKELL)
1192 scheduleGetRemoteWork(rtsBool *receivedFinish)
1194 ASSERT(EMPTY_RUN_QUEUE());
1196 if (RtsFlags.ParFlags.BufferTime) {
1197 IF_PAR_DEBUG(verbose,
1198 debugBelch("...send all pending data,"));
1201 for (i=1; i<=nPEs; i++)
1202 sendImmediately(i); // send all messages away immediately
1206 //++EDEN++ idle() , i.e. send all buffers, wait for work
1207 // suppress fishing in EDEN... just look for incoming messages
1208 // (blocking receive)
1209 IF_PAR_DEBUG(verbose,
1210 debugBelch("...wait for incoming messages...\n"));
1211 *receivedFinish = processMessages(); // blocking receive...
1213 // and reenter scheduling loop after having received something
1214 // (return rtsFalse below)
1216 # else /* activate SPARKS machinery */
1217 /* We get here, if we have no work, tried to activate a local spark, but still
1218 have no work. We try to get a remote spark, by sending a FISH message.
1219 Thread migration should be added here, and triggered when a sequence of
1220 fishes returns without work. */
1221 delay = (RtsFlags.ParFlags.fishDelay!=0ll ? RtsFlags.ParFlags.fishDelay : 0ll);
1223 /* =8-[ no local sparks => look for work on other PEs */
1225 * We really have absolutely no work. Send out a fish
1226 * (there may be some out there already), and wait for
1227 * something to arrive. We clearly can't run any threads
1228 * until a SCHEDULE or RESUME arrives, and so that's what
1229 * we're hoping to see. (Of course, we still have to
1230 * respond to other types of messages.)
1232 rtsTime now = msTime() /*CURRENT_TIME*/;
1233 IF_PAR_DEBUG(verbose,
1234 debugBelch("-- now=%ld\n", now));
1235 IF_PAR_DEBUG(fish, // verbose,
1236 if (outstandingFishes < RtsFlags.ParFlags.maxFishes &&
1237 (last_fish_arrived_at!=0 &&
1238 last_fish_arrived_at+delay > now)) {
1239 debugBelch("--$$ <%llu> delaying FISH until %llu (last fish %llu, delay %llu)\n",
1240 now, last_fish_arrived_at+delay,
1241 last_fish_arrived_at,
1245 if (outstandingFishes < RtsFlags.ParFlags.maxFishes &&
1246 advisory_thread_count < RtsFlags.ParFlags.maxThreads) { // send a FISH, but when?
1247 if (last_fish_arrived_at==0 ||
1248 (last_fish_arrived_at+delay <= now)) { // send FISH now!
1249 /* outstandingFishes is set in sendFish, processFish;
1250 avoid flooding system with fishes via delay */
1251 next_fish_to_send_at = 0;
1253 /* ToDo: this should be done in the main scheduling loop to avoid the
1254 busy wait here; not so bad if fish delay is very small */
1255 int iq = 0; // DEBUGGING -- HWL
1256 next_fish_to_send_at = last_fish_arrived_at+delay; // remember when to send
1257 /* send a fish when ready, but process messages that arrive in the meantime */
1259 if (PacketsWaiting()) {
1261 *receivedFinish = processMessages();
1264 } while (!*receivedFinish || now<next_fish_to_send_at);
1265 // JB: This means the fish could become obsolete, if we receive
1266 // work. Better check for work again?
1267 // last line: while (!receivedFinish || !haveWork || now<...)
1268 // next line: if (receivedFinish || haveWork )
1270 if (*receivedFinish) // no need to send a FISH if we are finishing anyway
1271 return rtsFalse; // NB: this will leave scheduler loop
1272 // immediately after return!
1274 IF_PAR_DEBUG(fish, // verbose,
1275 debugBelch("--$$ <%llu> sent delayed fish (%d processMessages); active/total threads=%d/%d\n",now,iq,run_queue_len(),advisory_thread_count));
1279 // JB: IMHO, this should all be hidden inside sendFish(...)
1281 sendFish(pe, thisPE, NEW_FISH_AGE, NEW_FISH_HISTORY,
1284 // Global statistics: count no. of fishes
1285 if (RtsFlags.ParFlags.ParStats.Global &&
1286 RtsFlags.GcFlags.giveStats > NO_GC_STATS) {
1287 globalParStats.tot_fish_mess++;
1291 /* delayed fishes must have been sent by now! */
1292 next_fish_to_send_at = 0;
1295 *receivedFinish = processMessages();
1296 # endif /* SPARKS */
1299 /* NB: this function always returns rtsFalse, meaning the scheduler
1300 loop continues with the next iteration;
1302 return code means success in finding work; we enter this function
1303 if there is no local work, thus have to send a fish which takes
1304 time until it arrives with work; in the meantime we should process
1305 messages in the main loop;
1308 #endif // PARALLEL_HASKELL
1310 /* ----------------------------------------------------------------------------
1311 * PAR/GRAN: Report stats & debugging info(?)
1312 * ------------------------------------------------------------------------- */
1314 #if defined(PAR) || defined(GRAN)
1316 scheduleGranParReport(void)
1318 ASSERT(run_queue_hd != END_TSO_QUEUE);
1320 /* Take a thread from the run queue, if we have work */
1321 POP_RUN_QUEUE(t); // take_off_run_queue(END_TSO_QUEUE);
1323 /* If this TSO has got its outport closed in the meantime,
1324 * it mustn't be run. Instead, we have to clean it up as if it was finished.
1325 * It has to be marked as TH_DEAD for this purpose.
1326 * If it is TH_TERM instead, it is supposed to have finished in the normal way.
1328 JB: TODO: investigate wether state change field could be nuked
1329 entirely and replaced by the normal tso state (whatnext
1330 field). All we want to do is to kill tsos from outside.
1333 /* ToDo: write something to the log-file
1334 if (RTSflags.ParFlags.granSimStats && !sameThread)
1335 DumpGranEvent(GR_SCHEDULE, RunnableThreadsHd);
1339 /* the spark pool for the current PE */
1340 pool = &(cap.r.rSparks); // cap = (old) MainCap
1343 debugBelch("--=^ %d threads, %d sparks on [%#x]\n",
1344 run_queue_len(), spark_queue_len(pool), CURRENT_PROC));
1347 debugBelch("--=^ %d threads, %d sparks on [%#x]\n",
1348 run_queue_len(), spark_queue_len(pool), CURRENT_PROC));
1350 if (RtsFlags.ParFlags.ParStats.Full &&
1351 (t->par.sparkname != (StgInt)0) && // only log spark generated threads
1352 (emitSchedule || // forced emit
1353 (t && LastTSO && t->id != LastTSO->id))) {
1355 we are running a different TSO, so write a schedule event to log file
1356 NB: If we use fair scheduling we also have to write a deschedule
1357 event for LastTSO; with unfair scheduling we know that the
1358 previous tso has blocked whenever we switch to another tso, so
1359 we don't need it in GUM for now
1361 IF_PAR_DEBUG(fish, // schedule,
1362 debugBelch("____ scheduling spark generated thread %d (%lx) (%lx) via a forced emit\n",t->id,t,t->par.sparkname));
1364 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
1365 GR_SCHEDULE, t, (StgClosure *)NULL, 0, 0);
1366 emitSchedule = rtsFalse;
1371 /* ----------------------------------------------------------------------------
1372 * After running a thread...
1373 * ASSUMES: sched_mutex
1374 * ------------------------------------------------------------------------- */
1377 schedulePostRunThread(void)
1380 /* HACK 675: if the last thread didn't yield, make sure to print a
1381 SCHEDULE event to the log file when StgRunning the next thread, even
1382 if it is the same one as before */
1384 TimeOfLastYield = CURRENT_TIME;
1387 /* some statistics gathering in the parallel case */
1389 #if defined(GRAN) || defined(PAR) || defined(EDEN)
1393 IF_DEBUG(gran, DumpGranEvent(GR_DESCHEDULE, t));
1394 globalGranStats.tot_heapover++;
1396 globalParStats.tot_heapover++;
1403 DumpGranEvent(GR_DESCHEDULE, t));
1404 globalGranStats.tot_stackover++;
1407 // DumpGranEvent(GR_DESCHEDULE, t);
1408 globalParStats.tot_stackover++;
1412 case ThreadYielding:
1415 DumpGranEvent(GR_DESCHEDULE, t));
1416 globalGranStats.tot_yields++;
1419 // DumpGranEvent(GR_DESCHEDULE, t);
1420 globalParStats.tot_yields++;
1427 debugBelch("--<< thread %ld (%p; %s) stopped, blocking on node %p [PE %d] with BQ: ",
1428 t->id, t, whatNext_strs[t->what_next], t->block_info.closure,
1429 (t->block_info.closure==(StgClosure*)NULL ? 99 : where_is(t->block_info.closure)));
1430 if (t->block_info.closure!=(StgClosure*)NULL)
1431 print_bq(t->block_info.closure);
1434 // ??? needed; should emit block before
1436 DumpGranEvent(GR_DESCHEDULE, t));
1437 prune_eventq(t, (StgClosure *)NULL); // prune ContinueThreads for t
1440 ASSERT(procStatus[CurrentProc]==Busy ||
1441 ((procStatus[CurrentProc]==Fetching) &&
1442 (t->block_info.closure!=(StgClosure*)NULL)));
1443 if (run_queue_hds[CurrentProc] == END_TSO_QUEUE &&
1444 !(!RtsFlags.GranFlags.DoAsyncFetch &&
1445 procStatus[CurrentProc]==Fetching))
1446 procStatus[CurrentProc] = Idle;
1449 //++PAR++ blockThread() writes the event (change?)
1453 case ThreadFinished:
1457 barf("parGlobalStats: unknown return code");
1463 /* -----------------------------------------------------------------------------
1464 * Handle a thread that returned to the scheduler with ThreadHeepOverflow
1465 * ASSUMES: sched_mutex
1466 * -------------------------------------------------------------------------- */
1469 scheduleHandleHeapOverflow( Capability *cap, StgTSO *t )
1471 // did the task ask for a large block?
1472 if (cap->r.rHpAlloc > BLOCK_SIZE) {
1473 // if so, get one and push it on the front of the nursery.
1477 blocks = (lnat)BLOCK_ROUND_UP(cap->r.rHpAlloc) / BLOCK_SIZE;
1480 debugBelch("--<< thread %ld (%s) stopped: requesting a large block (size %ld)\n",
1481 (long)t->id, whatNext_strs[t->what_next], blocks));
1483 // don't do this if the nursery is (nearly) full, we'll GC first.
1484 if (cap->r.rCurrentNursery->link != NULL ||
1485 cap->r.rNursery->n_blocks == 1) { // paranoia to prevent infinite loop
1486 // if the nursery has only one block.
1488 bd = allocGroup( blocks );
1489 cap->r.rNursery->n_blocks += blocks;
1491 // link the new group into the list
1492 bd->link = cap->r.rCurrentNursery;
1493 bd->u.back = cap->r.rCurrentNursery->u.back;
1494 if (cap->r.rCurrentNursery->u.back != NULL) {
1495 cap->r.rCurrentNursery->u.back->link = bd;
1498 ASSERT(g0s0->blocks == cap->r.rCurrentNursery &&
1499 g0s0 == cap->r.rNursery);
1501 cap->r.rNursery->blocks = bd;
1503 cap->r.rCurrentNursery->u.back = bd;
1505 // initialise it as a nursery block. We initialise the
1506 // step, gen_no, and flags field of *every* sub-block in
1507 // this large block, because this is easier than making
1508 // sure that we always find the block head of a large
1509 // block whenever we call Bdescr() (eg. evacuate() and
1510 // isAlive() in the GC would both have to do this, at
1514 for (x = bd; x < bd + blocks; x++) {
1515 x->step = cap->r.rNursery;
1521 // This assert can be a killer if the app is doing lots
1522 // of large block allocations.
1523 IF_DEBUG(sanity, checkNurserySanity(cap->r.rNursery));
1525 // now update the nursery to point to the new block
1526 cap->r.rCurrentNursery = bd;
1528 // we might be unlucky and have another thread get on the
1529 // run queue before us and steal the large block, but in that
1530 // case the thread will just end up requesting another large
1532 PUSH_ON_RUN_QUEUE(t);
1533 return rtsFalse; /* not actually GC'ing */
1538 debugBelch("--<< thread %ld (%s) stopped: HeapOverflow\n",
1539 (long)t->id, whatNext_strs[t->what_next]));
1541 ASSERT(!is_on_queue(t,CurrentProc));
1542 #elif defined(PARALLEL_HASKELL)
1543 /* Currently we emit a DESCHEDULE event before GC in GUM.
1544 ToDo: either add separate event to distinguish SYSTEM time from rest
1545 or just nuke this DESCHEDULE (and the following SCHEDULE) */
1546 if (0 && RtsFlags.ParFlags.ParStats.Full) {
1547 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
1548 GR_DESCHEDULE, t, (StgClosure *)NULL, 0, 0);
1549 emitSchedule = rtsTrue;
1553 PUSH_ON_RUN_QUEUE(t);
1555 /* actual GC is done at the end of the while loop in schedule() */
1558 /* -----------------------------------------------------------------------------
1559 * Handle a thread that returned to the scheduler with ThreadStackOverflow
1560 * ASSUMES: sched_mutex
1561 * -------------------------------------------------------------------------- */
1564 scheduleHandleStackOverflow( StgTSO *t)
1566 IF_DEBUG(scheduler,debugBelch("--<< thread %ld (%s) stopped, StackOverflow\n",
1567 (long)t->id, whatNext_strs[t->what_next]));
1568 /* just adjust the stack for this thread, then pop it back
1572 /* enlarge the stack */
1573 StgTSO *new_t = threadStackOverflow(t);
1575 /* This TSO has moved, so update any pointers to it from the
1576 * main thread stack. It better not be on any other queues...
1577 * (it shouldn't be).
1579 if (t->main != NULL) {
1580 t->main->tso = new_t;
1582 PUSH_ON_RUN_QUEUE(new_t);
1586 /* -----------------------------------------------------------------------------
1587 * Handle a thread that returned to the scheduler with ThreadYielding
1588 * ASSUMES: sched_mutex
1589 * -------------------------------------------------------------------------- */
1592 scheduleHandleYield( StgTSO *t, nat prev_what_next )
1594 // Reset the context switch flag. We don't do this just before
1595 // running the thread, because that would mean we would lose ticks
1596 // during GC, which can lead to unfair scheduling (a thread hogs
1597 // the CPU because the tick always arrives during GC). This way
1598 // penalises threads that do a lot of allocation, but that seems
1599 // better than the alternative.
1602 /* put the thread back on the run queue. Then, if we're ready to
1603 * GC, check whether this is the last task to stop. If so, wake
1604 * up the GC thread. getThread will block during a GC until the
1608 if (t->what_next != prev_what_next) {
1609 debugBelch("--<< thread %ld (%s) stopped to switch evaluators\n",
1610 (long)t->id, whatNext_strs[t->what_next]);
1612 debugBelch("--<< thread %ld (%s) stopped, yielding\n",
1613 (long)t->id, whatNext_strs[t->what_next]);
1618 //debugBelch("&& Doing sanity check on yielding TSO %ld.", t->id);
1620 ASSERT(t->link == END_TSO_QUEUE);
1622 // Shortcut if we're just switching evaluators: don't bother
1623 // doing stack squeezing (which can be expensive), just run the
1625 if (t->what_next != prev_what_next) {
1630 ASSERT(!is_on_queue(t,CurrentProc));
1633 //debugBelch("&& Doing sanity check on all ThreadQueues (and their TSOs).");
1634 checkThreadQsSanity(rtsTrue));
1641 /* add a ContinueThread event to actually process the thread */
1642 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
1644 t, (StgClosure*)NULL, (rtsSpark*)NULL);
1646 debugBelch("GRAN: eventq and runnableq after adding yielded thread to queue again:\n");
1653 /* -----------------------------------------------------------------------------
1654 * Handle a thread that returned to the scheduler with ThreadBlocked
1655 * ASSUMES: sched_mutex
1656 * -------------------------------------------------------------------------- */
1659 scheduleHandleThreadBlocked( StgTSO *t
1660 #if !defined(GRAN) && !defined(DEBUG)
1667 debugBelch("--<< thread %ld (%p; %s) stopped, blocking on node %p [PE %d] with BQ: \n",
1668 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)));
1669 if (t->block_info.closure!=(StgClosure*)NULL) print_bq(t->block_info.closure));
1671 // ??? needed; should emit block before
1673 DumpGranEvent(GR_DESCHEDULE, t));
1674 prune_eventq(t, (StgClosure *)NULL); // prune ContinueThreads for t
1677 ASSERT(procStatus[CurrentProc]==Busy ||
1684 if (RtsFlags.GranFlags.GranSimStats.Full)
1685 DumpGranEvent(GR_START,tso);
1686 #elif defined(PARALLEL_HASKELL)
1687 if (RtsFlags.ParFlags.ParStats.Full)
1688 DumpGranEvent(GR_STARTQ,tso);
1689 /* HACk to avoid SCHEDULE
1693 /* Link the new thread on the global thread list.
1695 tso->global_link = all_threads;
1699 tso->dist.priority = MandatoryPriority; //by default that is...
1703 tso->gran.pri = pri;
1705 tso->gran.magic = TSO_MAGIC; // debugging only
1707 tso->gran.sparkname = 0;
1708 tso->gran.startedat = CURRENT_TIME;
1709 tso->gran.exported = 0;
1710 tso->gran.basicblocks = 0;
1711 tso->gran.allocs = 0;
1712 tso->gran.exectime = 0;
1713 tso->gran.fetchtime = 0;
1714 tso->gran.fetchcount = 0;
1715 tso->gran.blocktime = 0;
1716 tso->gran.blockcount = 0;
1717 tso->gran.blockedat = 0;
1718 tso->gran.globalsparks = 0;
1719 tso->gran.localsparks = 0;
1720 if (RtsFlags.GranFlags.Light)
1721 tso->gran.clock = Now; /* local clock */
1723 tso->gran.clock = 0;
1725 IF_DEBUG(gran,printTSO(tso));
1726 #elif defined(PARALLEL_HASKELL)
1728 tso->par.magic = TSO_MAGIC; // debugging only
1730 tso->par.sparkname = 0;
1731 tso->par.startedat = CURRENT_TIME;
1732 tso->par.exported = 0;
1733 tso->par.basicblocks = 0;
1734 tso->par.allocs = 0;
1735 tso->par.exectime = 0;
1736 tso->par.fetchtime = 0;
1737 tso->par.fetchcount = 0;
1738 tso->par.blocktime = 0;
1739 tso->par.blockcount = 0;
1740 tso->par.blockedat = 0;
1741 tso->par.globalsparks = 0;
1742 tso->par.localsparks = 0;
1746 globalGranStats.tot_threads_created++;
1747 globalGranStats.threads_created_on_PE[CurrentProc]++;
1748 globalGranStats.tot_sq_len += spark_queue_len(CurrentProc);
1749 globalGranStats.tot_sq_probes++;
1750 #elif defined(PARALLEL_HASKELL)
1751 // collect parallel global statistics (currently done together with GC stats)
1752 if (RtsFlags.ParFlags.ParStats.Global &&
1753 RtsFlags.GcFlags.giveStats > NO_GC_STATS) {
1754 //debugBelch("Creating thread %d @ %11.2f\n", tso->id, usertime());
1755 globalParStats.tot_threads_created++;
1761 sched_belch("==__ schedule: Created TSO %d (%p);",
1762 CurrentProc, tso, tso->id));
1763 #elif defined(PARALLEL_HASKELL)
1764 IF_PAR_DEBUG(verbose,
1765 sched_belch("==__ schedule: Created TSO %d (%p); %d threads active",
1766 (long)tso->id, tso, advisory_thread_count));
1768 IF_DEBUG(scheduler,sched_belch("created thread %ld, stack size = %lx words",
1769 (long)tso->id, (long)tso->stack_size));
1776 all parallel thread creation calls should fall through the following routine.
1779 createThreadFromSpark(rtsSpark spark)
1781 ASSERT(spark != (rtsSpark)NULL);
1782 // JB: TAKE CARE OF THIS COUNTER! BUGGY
1783 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads)
1785 barf("{createSparkThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
1786 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
1787 return END_TSO_QUEUE;
1791 tso = createThread(RtsFlags.GcFlags.initialStkSize);
1792 if (tso==END_TSO_QUEUE)
1793 barf("createSparkThread: Cannot create TSO");
1795 tso->priority = AdvisoryPriority;
1797 pushClosure(tso,spark);
1799 advisory_thread_count++; // JB: TAKE CARE OF THIS COUNTER! BUGGY
1806 Turn a spark into a thread.
1807 ToDo: fix for SMP (needs to acquire SCHED_MUTEX!)
1811 activateSpark (rtsSpark spark)
1815 tso = createSparkThread(spark);
1816 if (RtsFlags.ParFlags.ParStats.Full) {
1817 //ASSERT(run_queue_hd == END_TSO_QUEUE); // I think ...
1818 IF_PAR_DEBUG(verbose,
1819 debugBelch("==^^ activateSpark: turning spark of closure %p (%s) into a thread\n",
1820 (StgClosure *)spark, info_type((StgClosure *)spark)));
1822 // ToDo: fwd info on local/global spark to thread -- HWL
1823 // tso->gran.exported = spark->exported;
1824 // tso->gran.locked = !spark->global;
1825 // tso->gran.sparkname = spark->name;
1831 /* ---------------------------------------------------------------------------
1834 * scheduleThread puts a thread on the head of the runnable queue.
1835 * This will usually be done immediately after a thread is created.
1836 * The caller of scheduleThread must create the thread using e.g.
1837 * createThread and push an appropriate closure
1838 * on this thread's stack before the scheduler is invoked.
1839 * ------------------------------------------------------------------------ */
1842 scheduleThread_(StgTSO *tso)
1844 // The thread goes at the *end* of the run-queue, to avoid possible
1845 // starvation of any threads already on the queue.
1846 APPEND_TO_RUN_QUEUE(tso);
1851 scheduleThread(StgTSO* tso)
1853 ACQUIRE_LOCK(&sched_mutex);
1854 scheduleThread_(tso);
1855 RELEASE_LOCK(&sched_mutex);
1858 #if defined(RTS_SUPPORTS_THREADS)
1859 static Condition bound_cond_cache;
1860 static int bound_cond_cache_full = 0;
1865 scheduleWaitThread(StgTSO* tso, /*[out]*/HaskellObj* ret,
1866 Capability *initialCapability)
1868 // Precondition: sched_mutex must be held
1871 m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
1876 m->link = main_threads;
1878 if (main_threads != NULL) {
1879 main_threads->prev = m;
1883 #if defined(RTS_SUPPORTS_THREADS)
1884 // Allocating a new condition for each thread is expensive, so we
1885 // cache one. This is a pretty feeble hack, but it helps speed up
1886 // consecutive call-ins quite a bit.
1887 if (bound_cond_cache_full) {
1888 m->bound_thread_cond = bound_cond_cache;
1889 bound_cond_cache_full = 0;
1891 initCondition(&m->bound_thread_cond);
1895 /* Put the thread on the main-threads list prior to scheduling the TSO.
1896 Failure to do so introduces a race condition in the MT case (as
1897 identified by Wolfgang Thaller), whereby the new task/OS thread
1898 created by scheduleThread_() would complete prior to the thread
1899 that spawned it managed to put 'itself' on the main-threads list.
1900 The upshot of it all being that the worker thread wouldn't get to
1901 signal the completion of the its work item for the main thread to
1902 see (==> it got stuck waiting.) -- sof 6/02.
1904 IF_DEBUG(scheduler, sched_belch("waiting for thread (%d)", tso->id));
1906 APPEND_TO_RUN_QUEUE(tso);
1907 // NB. Don't call threadRunnable() here, because the thread is
1908 // bound and only runnable by *this* OS thread, so waking up other
1909 // workers will just slow things down.
1911 return waitThread_(m, initialCapability);
1914 /* ---------------------------------------------------------------------------
1917 * Initialise the scheduler. This resets all the queues - if the
1918 * queues contained any threads, they'll be garbage collected at the
1921 * ------------------------------------------------------------------------ */
1929 for (i=0; i<=MAX_PROC; i++) {
1930 run_queue_hds[i] = END_TSO_QUEUE;
1931 run_queue_tls[i] = END_TSO_QUEUE;
1932 blocked_queue_hds[i] = END_TSO_QUEUE;
1933 blocked_queue_tls[i] = END_TSO_QUEUE;
1934 ccalling_threadss[i] = END_TSO_QUEUE;
1935 blackhole_queue[i] = END_TSO_QUEUE;
1936 sleeping_queue = END_TSO_QUEUE;
1939 run_queue_hd = END_TSO_QUEUE;
1940 run_queue_tl = END_TSO_QUEUE;
1941 blocked_queue_hd = END_TSO_QUEUE;
1942 blocked_queue_tl = END_TSO_QUEUE;
1943 blackhole_queue = END_TSO_QUEUE;
1944 sleeping_queue = END_TSO_QUEUE;
1947 suspended_ccalling_threads = END_TSO_QUEUE;
1949 main_threads = NULL;
1950 all_threads = END_TSO_QUEUE;
1955 RtsFlags.ConcFlags.ctxtSwitchTicks =
1956 RtsFlags.ConcFlags.ctxtSwitchTime / TICK_MILLISECS;
1958 #if defined(RTS_SUPPORTS_THREADS)
1959 /* Initialise the mutex and condition variables used by
1961 initMutex(&sched_mutex);
1962 initMutex(&term_mutex);
1965 ACQUIRE_LOCK(&sched_mutex);
1967 /* A capability holds the state a native thread needs in
1968 * order to execute STG code. At least one capability is
1969 * floating around (only SMP builds have more than one).
1973 #if defined(RTS_SUPPORTS_THREADS)
1978 /* eagerly start some extra workers */
1979 startingWorkerThread = RtsFlags.ParFlags.nNodes;
1980 startTasks(RtsFlags.ParFlags.nNodes, taskStart);
1983 #if /* defined(SMP) ||*/ defined(PARALLEL_HASKELL)
1987 RELEASE_LOCK(&sched_mutex);
1991 exitScheduler( void )
1993 interrupted = rtsTrue;
1994 shutting_down_scheduler = rtsTrue;
1995 #if defined(RTS_SUPPORTS_THREADS)
1996 if (threadIsTask(osThreadId())) { taskStop(); }
2001 /* ----------------------------------------------------------------------------
2002 Managing the per-task allocation areas.
2004 Each capability comes with an allocation area. These are
2005 fixed-length block lists into which allocation can be done.
2007 ToDo: no support for two-space collection at the moment???
2008 ------------------------------------------------------------------------- */
2010 static SchedulerStatus
2011 waitThread_(StgMainThread* m, Capability *initialCapability)
2013 SchedulerStatus stat;
2015 // Precondition: sched_mutex must be held.
2016 IF_DEBUG(scheduler, sched_belch("new main thread (%d)", m->tso->id));
2019 /* GranSim specific init */
2020 CurrentTSO = m->tso; // the TSO to run
2021 procStatus[MainProc] = Busy; // status of main PE
2022 CurrentProc = MainProc; // PE to run it on
2023 schedule(m,initialCapability);
2025 schedule(m,initialCapability);
2026 ASSERT(m->stat != NoStatus);
2031 #if defined(RTS_SUPPORTS_THREADS)
2032 // Free the condition variable, returning it to the cache if possible.
2033 if (!bound_cond_cache_full) {
2034 bound_cond_cache = m->bound_thread_cond;
2035 bound_cond_cache_full = 1;
2037 closeCondition(&m->bound_thread_cond);
2041 IF_DEBUG(scheduler, sched_belch("main thread (%d) finished", m->tso->id));
2044 // Postcondition: sched_mutex still held
2048 /* ---------------------------------------------------------------------------
2049 Where are the roots that we know about?
2051 - all the threads on the runnable queue
2052 - all the threads on the blocked queue
2053 - all the threads on the sleeping queue
2054 - all the thread currently executing a _ccall_GC
2055 - all the "main threads"
2057 ------------------------------------------------------------------------ */
2059 /* This has to be protected either by the scheduler monitor, or by the
2060 garbage collection monitor (probably the latter).
2065 GetRoots( evac_fn evac )
2070 for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
2071 if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
2072 evac((StgClosure **)&run_queue_hds[i]);
2073 if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
2074 evac((StgClosure **)&run_queue_tls[i]);
2076 if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
2077 evac((StgClosure **)&blocked_queue_hds[i]);
2078 if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
2079 evac((StgClosure **)&blocked_queue_tls[i]);
2080 if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
2081 evac((StgClosure **)&ccalling_threads[i]);
2088 if (run_queue_hd != END_TSO_QUEUE) {
2089 ASSERT(run_queue_tl != END_TSO_QUEUE);
2090 evac((StgClosure **)&run_queue_hd);
2091 evac((StgClosure **)&run_queue_tl);
2094 if (blocked_queue_hd != END_TSO_QUEUE) {
2095 ASSERT(blocked_queue_tl != END_TSO_QUEUE);
2096 evac((StgClosure **)&blocked_queue_hd);
2097 evac((StgClosure **)&blocked_queue_tl);
2100 if (sleeping_queue != END_TSO_QUEUE) {
2101 evac((StgClosure **)&sleeping_queue);
2105 if (blackhole_queue != END_TSO_QUEUE) {
2106 evac((StgClosure **)&blackhole_queue);
2109 if (suspended_ccalling_threads != END_TSO_QUEUE) {
2110 evac((StgClosure **)&suspended_ccalling_threads);
2113 #if defined(PARALLEL_HASKELL) || defined(GRAN)
2114 markSparkQueue(evac);
2117 #if defined(RTS_USER_SIGNALS)
2118 // mark the signal handlers (signals should be already blocked)
2119 markSignalHandlers(evac);
2123 /* -----------------------------------------------------------------------------
2126 This is the interface to the garbage collector from Haskell land.
2127 We provide this so that external C code can allocate and garbage
2128 collect when called from Haskell via _ccall_GC.
2130 It might be useful to provide an interface whereby the programmer
2131 can specify more roots (ToDo).
2133 This needs to be protected by the GC condition variable above. KH.
2134 -------------------------------------------------------------------------- */
2136 static void (*extra_roots)(evac_fn);
2141 /* Obligated to hold this lock upon entry */
2142 ACQUIRE_LOCK(&sched_mutex);
2143 GarbageCollect(GetRoots,rtsFalse);
2144 RELEASE_LOCK(&sched_mutex);
2148 performMajorGC(void)
2150 ACQUIRE_LOCK(&sched_mutex);
2151 GarbageCollect(GetRoots,rtsTrue);
2152 RELEASE_LOCK(&sched_mutex);
2156 AllRoots(evac_fn evac)
2158 GetRoots(evac); // the scheduler's roots
2159 extra_roots(evac); // the user's roots
2163 performGCWithRoots(void (*get_roots)(evac_fn))
2165 ACQUIRE_LOCK(&sched_mutex);
2166 extra_roots = get_roots;
2167 GarbageCollect(AllRoots,rtsFalse);
2168 RELEASE_LOCK(&sched_mutex);
2171 /* -----------------------------------------------------------------------------
2174 If the thread has reached its maximum stack size, then raise the
2175 StackOverflow exception in the offending thread. Otherwise
2176 relocate the TSO into a larger chunk of memory and adjust its stack
2178 -------------------------------------------------------------------------- */
2181 threadStackOverflow(StgTSO *tso)
2183 nat new_stack_size, stack_words;
2188 IF_DEBUG(sanity,checkTSO(tso));
2189 if (tso->stack_size >= tso->max_stack_size) {
2192 debugBelch("@@ threadStackOverflow of TSO %ld (%p): stack too large (now %ld; max is %ld)\n",
2193 (long)tso->id, tso, (long)tso->stack_size, (long)tso->max_stack_size);
2194 /* If we're debugging, just print out the top of the stack */
2195 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2198 /* Send this thread the StackOverflow exception */
2199 raiseAsync(tso, (StgClosure *)stackOverflow_closure);
2203 /* Try to double the current stack size. If that takes us over the
2204 * maximum stack size for this thread, then use the maximum instead.
2205 * Finally round up so the TSO ends up as a whole number of blocks.
2207 new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
2208 new_tso_size = (lnat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
2209 TSO_STRUCT_SIZE)/sizeof(W_);
2210 new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
2211 new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
2213 IF_DEBUG(scheduler, debugBelch("== sched: increasing stack size from %d words to %d.\n", tso->stack_size, new_stack_size));
2215 dest = (StgTSO *)allocate(new_tso_size);
2216 TICK_ALLOC_TSO(new_stack_size,0);
2218 /* copy the TSO block and the old stack into the new area */
2219 memcpy(dest,tso,TSO_STRUCT_SIZE);
2220 stack_words = tso->stack + tso->stack_size - tso->sp;
2221 new_sp = (P_)dest + new_tso_size - stack_words;
2222 memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
2224 /* relocate the stack pointers... */
2226 dest->stack_size = new_stack_size;
2228 /* Mark the old TSO as relocated. We have to check for relocated
2229 * TSOs in the garbage collector and any primops that deal with TSOs.
2231 * It's important to set the sp value to just beyond the end
2232 * of the stack, so we don't attempt to scavenge any part of the
2235 tso->what_next = ThreadRelocated;
2237 tso->sp = (P_)&(tso->stack[tso->stack_size]);
2238 tso->why_blocked = NotBlocked;
2240 IF_PAR_DEBUG(verbose,
2241 debugBelch("@@ threadStackOverflow of TSO %d (now at %p): stack size increased to %ld\n",
2242 tso->id, tso, tso->stack_size);
2243 /* If we're debugging, just print out the top of the stack */
2244 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2247 IF_DEBUG(sanity,checkTSO(tso));
2249 IF_DEBUG(scheduler,printTSO(dest));
2255 /* ---------------------------------------------------------------------------
2256 Wake up a queue that was blocked on some resource.
2257 ------------------------------------------------------------------------ */
2261 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2264 #elif defined(PARALLEL_HASKELL)
2266 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2268 /* write RESUME events to log file and
2269 update blocked and fetch time (depending on type of the orig closure) */
2270 if (RtsFlags.ParFlags.ParStats.Full) {
2271 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
2272 GR_RESUMEQ, ((StgTSO *)bqe), ((StgTSO *)bqe)->block_info.closure,
2273 0, 0 /* spark_queue_len(ADVISORY_POOL) */);
2274 if (EMPTY_RUN_QUEUE())
2275 emitSchedule = rtsTrue;
2277 switch (get_itbl(node)->type) {
2279 ((StgTSO *)bqe)->par.fetchtime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2284 ((StgTSO *)bqe)->par.blocktime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2291 barf("{unblockOneLocked}Daq Qagh: unexpected closure in blocking queue");
2298 StgBlockingQueueElement *
2299 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2302 PEs node_loc, tso_loc;
2304 node_loc = where_is(node); // should be lifted out of loop
2305 tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2306 tso_loc = where_is((StgClosure *)tso);
2307 if (IS_LOCAL_TO(PROCS(node),tso_loc)) { // TSO is local
2308 /* !fake_fetch => TSO is on CurrentProc is same as IS_LOCAL_TO */
2309 ASSERT(CurrentProc!=node_loc || tso_loc==CurrentProc);
2310 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.lunblocktime;
2311 // insertThread(tso, node_loc);
2312 new_event(tso_loc, tso_loc, CurrentTime[CurrentProc],
2314 tso, node, (rtsSpark*)NULL);
2315 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2318 } else { // TSO is remote (actually should be FMBQ)
2319 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.mpacktime +
2320 RtsFlags.GranFlags.Costs.gunblocktime +
2321 RtsFlags.GranFlags.Costs.latency;
2322 new_event(tso_loc, CurrentProc, CurrentTime[CurrentProc],
2324 tso, node, (rtsSpark*)NULL);
2325 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2328 /* the thread-queue-overhead is accounted for in either Resume or UnblockThread */
2330 debugBelch(" %s TSO %d (%p) [PE %d] (block_info.closure=%p) (next=%p) ,",
2331 (node_loc==tso_loc ? "Local" : "Global"),
2332 tso->id, tso, CurrentProc, tso->block_info.closure, tso->link));
2333 tso->block_info.closure = NULL;
2334 IF_DEBUG(scheduler,debugBelch("-- Waking up thread %ld (%p)\n",
2337 #elif defined(PARALLEL_HASKELL)
2338 StgBlockingQueueElement *
2339 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2341 StgBlockingQueueElement *next;
2343 switch (get_itbl(bqe)->type) {
2345 ASSERT(((StgTSO *)bqe)->why_blocked != NotBlocked);
2346 /* if it's a TSO just push it onto the run_queue */
2348 ((StgTSO *)bqe)->link = END_TSO_QUEUE; // debugging?
2349 APPEND_TO_RUN_QUEUE((StgTSO *)bqe);
2351 unblockCount(bqe, node);
2352 /* reset blocking status after dumping event */
2353 ((StgTSO *)bqe)->why_blocked = NotBlocked;
2357 /* if it's a BLOCKED_FETCH put it on the PendingFetches list */
2359 bqe->link = (StgBlockingQueueElement *)PendingFetches;
2360 PendingFetches = (StgBlockedFetch *)bqe;
2364 /* can ignore this case in a non-debugging setup;
2365 see comments on RBHSave closures above */
2367 /* check that the closure is an RBHSave closure */
2368 ASSERT(get_itbl((StgClosure *)bqe) == &stg_RBH_Save_0_info ||
2369 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_1_info ||
2370 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_2_info);
2374 barf("{unblockOneLocked}Daq Qagh: Unexpected IP (%#lx; %s) in blocking queue at %#lx\n",
2375 get_itbl((StgClosure *)bqe), info_type((StgClosure *)bqe),
2379 IF_PAR_DEBUG(bq, debugBelch(", %p (%s)\n", bqe, info_type((StgClosure*)bqe)));
2383 #else /* !GRAN && !PARALLEL_HASKELL */
2385 unblockOneLocked(StgTSO *tso)
2389 ASSERT(get_itbl(tso)->type == TSO);
2390 ASSERT(tso->why_blocked != NotBlocked);
2391 tso->why_blocked = NotBlocked;
2393 tso->link = END_TSO_QUEUE;
2394 APPEND_TO_RUN_QUEUE(tso);
2396 IF_DEBUG(scheduler,sched_belch("waking up thread %ld", (long)tso->id));
2401 #if defined(GRAN) || defined(PARALLEL_HASKELL)
2402 INLINE_ME StgBlockingQueueElement *
2403 unblockOne(StgBlockingQueueElement *bqe, StgClosure *node)
2405 ACQUIRE_LOCK(&sched_mutex);
2406 bqe = unblockOneLocked(bqe, node);
2407 RELEASE_LOCK(&sched_mutex);
2412 unblockOne(StgTSO *tso)
2414 ACQUIRE_LOCK(&sched_mutex);
2415 tso = unblockOneLocked(tso);
2416 RELEASE_LOCK(&sched_mutex);
2423 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2425 StgBlockingQueueElement *bqe;
2430 debugBelch("##-_ AwBQ for node %p on PE %d @ %ld by TSO %d (%p): \n", \
2431 node, CurrentProc, CurrentTime[CurrentProc],
2432 CurrentTSO->id, CurrentTSO));
2434 node_loc = where_is(node);
2436 ASSERT(q == END_BQ_QUEUE ||
2437 get_itbl(q)->type == TSO || // q is either a TSO or an RBHSave
2438 get_itbl(q)->type == CONSTR); // closure (type constructor)
2439 ASSERT(is_unique(node));
2441 /* FAKE FETCH: magically copy the node to the tso's proc;
2442 no Fetch necessary because in reality the node should not have been
2443 moved to the other PE in the first place
2445 if (CurrentProc!=node_loc) {
2447 debugBelch("## node %p is on PE %d but CurrentProc is %d (TSO %d); assuming fake fetch and adjusting bitmask (old: %#x)\n",
2448 node, node_loc, CurrentProc, CurrentTSO->id,
2449 // CurrentTSO, where_is(CurrentTSO),
2450 node->header.gran.procs));
2451 node->header.gran.procs = (node->header.gran.procs) | PE_NUMBER(CurrentProc);
2453 debugBelch("## new bitmask of node %p is %#x\n",
2454 node, node->header.gran.procs));
2455 if (RtsFlags.GranFlags.GranSimStats.Global) {
2456 globalGranStats.tot_fake_fetches++;
2461 // ToDo: check: ASSERT(CurrentProc==node_loc);
2462 while (get_itbl(bqe)->type==TSO) { // q != END_TSO_QUEUE) {
2465 bqe points to the current element in the queue
2466 next points to the next element in the queue
2468 //tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2469 //tso_loc = where_is(tso);
2471 bqe = unblockOneLocked(bqe, node);
2474 /* if this is the BQ of an RBH, we have to put back the info ripped out of
2475 the closure to make room for the anchor of the BQ */
2476 if (bqe!=END_BQ_QUEUE) {
2477 ASSERT(get_itbl(node)->type == RBH && get_itbl(bqe)->type == CONSTR);
2479 ASSERT((info_ptr==&RBH_Save_0_info) ||
2480 (info_ptr==&RBH_Save_1_info) ||
2481 (info_ptr==&RBH_Save_2_info));
2483 /* cf. convertToRBH in RBH.c for writing the RBHSave closure */
2484 ((StgRBH *)node)->blocking_queue = (StgBlockingQueueElement *)((StgRBHSave *)bqe)->payload[0];
2485 ((StgRBH *)node)->mut_link = (StgMutClosure *)((StgRBHSave *)bqe)->payload[1];
2488 debugBelch("## Filled in RBH_Save for %p (%s) at end of AwBQ\n",
2489 node, info_type(node)));
2492 /* statistics gathering */
2493 if (RtsFlags.GranFlags.GranSimStats.Global) {
2494 // globalGranStats.tot_bq_processing_time += bq_processing_time;
2495 globalGranStats.tot_bq_len += len; // total length of all bqs awakened
2496 // globalGranStats.tot_bq_len_local += len_local; // same for local TSOs only
2497 globalGranStats.tot_awbq++; // total no. of bqs awakened
2500 debugBelch("## BQ Stats of %p: [%d entries] %s\n",
2501 node, len, (bqe!=END_BQ_QUEUE) ? "RBH" : ""));
2503 #elif defined(PARALLEL_HASKELL)
2505 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2507 StgBlockingQueueElement *bqe;
2509 ACQUIRE_LOCK(&sched_mutex);
2511 IF_PAR_DEBUG(verbose,
2512 debugBelch("##-_ AwBQ for node %p on [%x]: \n",
2516 if(get_itbl(q)->type == CONSTR || q==END_BQ_QUEUE) {
2517 IF_PAR_DEBUG(verbose, debugBelch("## ... nothing to unblock so lets just return. RFP (BUG?)\n"));
2522 ASSERT(q == END_BQ_QUEUE ||
2523 get_itbl(q)->type == TSO ||
2524 get_itbl(q)->type == BLOCKED_FETCH ||
2525 get_itbl(q)->type == CONSTR);
2528 while (get_itbl(bqe)->type==TSO ||
2529 get_itbl(bqe)->type==BLOCKED_FETCH) {
2530 bqe = unblockOneLocked(bqe, node);
2532 RELEASE_LOCK(&sched_mutex);
2535 #else /* !GRAN && !PARALLEL_HASKELL */
2538 awakenBlockedQueueNoLock(StgTSO *tso)
2540 while (tso != END_TSO_QUEUE) {
2541 tso = unblockOneLocked(tso);
2546 awakenBlockedQueue(StgTSO *tso)
2548 ACQUIRE_LOCK(&sched_mutex);
2549 while (tso != END_TSO_QUEUE) {
2550 tso = unblockOneLocked(tso);
2552 RELEASE_LOCK(&sched_mutex);
2556 /* ---------------------------------------------------------------------------
2558 - usually called inside a signal handler so it mustn't do anything fancy.
2559 ------------------------------------------------------------------------ */
2562 interruptStgRts(void)
2567 /* ToDo: if invoked from a signal handler, this threadRunnable
2568 * only works if there's another thread (not this one) waiting to
2573 /* -----------------------------------------------------------------------------
2576 This is for use when we raise an exception in another thread, which
2578 This has nothing to do with the UnblockThread event in GranSim. -- HWL
2579 -------------------------------------------------------------------------- */
2581 #if defined(GRAN) || defined(PARALLEL_HASKELL)
2583 NB: only the type of the blocking queue is different in GranSim and GUM
2584 the operations on the queue-elements are the same
2585 long live polymorphism!
2587 Locks: sched_mutex is held upon entry and exit.
2591 unblockThread(StgTSO *tso)
2593 StgBlockingQueueElement *t, **last;
2595 switch (tso->why_blocked) {
2598 return; /* not blocked */
2601 // Be careful: nothing to do here! We tell the scheduler that the thread
2602 // is runnable and we leave it to the stack-walking code to abort the
2603 // transaction while unwinding the stack. We should perhaps have a debugging
2604 // test to make sure that this really happens and that the 'zombie' transaction
2605 // does not get committed.
2609 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
2611 StgBlockingQueueElement *last_tso = END_BQ_QUEUE;
2612 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
2614 last = (StgBlockingQueueElement **)&mvar->head;
2615 for (t = (StgBlockingQueueElement *)mvar->head;
2617 last = &t->link, last_tso = t, t = t->link) {
2618 if (t == (StgBlockingQueueElement *)tso) {
2619 *last = (StgBlockingQueueElement *)tso->link;
2620 if (mvar->tail == tso) {
2621 mvar->tail = (StgTSO *)last_tso;
2626 barf("unblockThread (MVAR): TSO not found");
2629 case BlockedOnBlackHole:
2630 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
2632 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
2634 last = &bq->blocking_queue;
2635 for (t = bq->blocking_queue;
2637 last = &t->link, t = t->link) {
2638 if (t == (StgBlockingQueueElement *)tso) {
2639 *last = (StgBlockingQueueElement *)tso->link;
2643 barf("unblockThread (BLACKHOLE): TSO not found");
2646 case BlockedOnException:
2648 StgTSO *target = tso->block_info.tso;
2650 ASSERT(get_itbl(target)->type == TSO);
2652 if (target->what_next == ThreadRelocated) {
2653 target = target->link;
2654 ASSERT(get_itbl(target)->type == TSO);
2657 ASSERT(target->blocked_exceptions != NULL);
2659 last = (StgBlockingQueueElement **)&target->blocked_exceptions;
2660 for (t = (StgBlockingQueueElement *)target->blocked_exceptions;
2662 last = &t->link, t = t->link) {
2663 ASSERT(get_itbl(t)->type == TSO);
2664 if (t == (StgBlockingQueueElement *)tso) {
2665 *last = (StgBlockingQueueElement *)tso->link;
2669 barf("unblockThread (Exception): TSO not found");
2673 case BlockedOnWrite:
2674 #if defined(mingw32_HOST_OS)
2675 case BlockedOnDoProc:
2678 /* take TSO off blocked_queue */
2679 StgBlockingQueueElement *prev = NULL;
2680 for (t = (StgBlockingQueueElement *)blocked_queue_hd; t != END_BQ_QUEUE;
2681 prev = t, t = t->link) {
2682 if (t == (StgBlockingQueueElement *)tso) {
2684 blocked_queue_hd = (StgTSO *)t->link;
2685 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
2686 blocked_queue_tl = END_TSO_QUEUE;
2689 prev->link = t->link;
2690 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
2691 blocked_queue_tl = (StgTSO *)prev;
2694 #if defined(mingw32_HOST_OS)
2695 /* (Cooperatively) signal that the worker thread should abort
2698 abandonWorkRequest(tso->block_info.async_result->reqID);
2703 barf("unblockThread (I/O): TSO not found");
2706 case BlockedOnDelay:
2708 /* take TSO off sleeping_queue */
2709 StgBlockingQueueElement *prev = NULL;
2710 for (t = (StgBlockingQueueElement *)sleeping_queue; t != END_BQ_QUEUE;
2711 prev = t, t = t->link) {
2712 if (t == (StgBlockingQueueElement *)tso) {
2714 sleeping_queue = (StgTSO *)t->link;
2716 prev->link = t->link;
2721 barf("unblockThread (delay): TSO not found");
2725 barf("unblockThread");
2729 tso->link = END_TSO_QUEUE;
2730 tso->why_blocked = NotBlocked;
2731 tso->block_info.closure = NULL;
2732 PUSH_ON_RUN_QUEUE(tso);
2736 unblockThread(StgTSO *tso)
2740 /* To avoid locking unnecessarily. */
2741 if (tso->why_blocked == NotBlocked) {
2745 switch (tso->why_blocked) {
2748 // Be careful: nothing to do here! We tell the scheduler that the thread
2749 // is runnable and we leave it to the stack-walking code to abort the
2750 // transaction while unwinding the stack. We should perhaps have a debugging
2751 // test to make sure that this really happens and that the 'zombie' transaction
2752 // does not get committed.
2756 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
2758 StgTSO *last_tso = END_TSO_QUEUE;
2759 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
2762 for (t = mvar->head; t != END_TSO_QUEUE;
2763 last = &t->link, last_tso = t, t = t->link) {
2766 if (mvar->tail == tso) {
2767 mvar->tail = last_tso;
2772 barf("unblockThread (MVAR): TSO not found");
2775 case BlockedOnBlackHole:
2777 last = &blackhole_queue;
2778 for (t = blackhole_queue; t != END_TSO_QUEUE;
2779 last = &t->link, t = t->link) {
2785 barf("unblockThread (BLACKHOLE): TSO not found");
2788 case BlockedOnException:
2790 StgTSO *target = tso->block_info.tso;
2792 ASSERT(get_itbl(target)->type == TSO);
2794 while (target->what_next == ThreadRelocated) {
2795 target = target->link;
2796 ASSERT(get_itbl(target)->type == TSO);
2799 ASSERT(target->blocked_exceptions != NULL);
2801 last = &target->blocked_exceptions;
2802 for (t = target->blocked_exceptions; t != END_TSO_QUEUE;
2803 last = &t->link, t = t->link) {
2804 ASSERT(get_itbl(t)->type == TSO);
2810 barf("unblockThread (Exception): TSO not found");
2814 case BlockedOnWrite:
2815 #if defined(mingw32_HOST_OS)
2816 case BlockedOnDoProc:
2819 StgTSO *prev = NULL;
2820 for (t = blocked_queue_hd; t != END_TSO_QUEUE;
2821 prev = t, t = t->link) {
2824 blocked_queue_hd = t->link;
2825 if (blocked_queue_tl == t) {
2826 blocked_queue_tl = END_TSO_QUEUE;
2829 prev->link = t->link;
2830 if (blocked_queue_tl == t) {
2831 blocked_queue_tl = prev;
2834 #if defined(mingw32_HOST_OS)
2835 /* (Cooperatively) signal that the worker thread should abort
2838 abandonWorkRequest(tso->block_info.async_result->reqID);
2843 barf("unblockThread (I/O): TSO not found");
2846 case BlockedOnDelay:
2848 StgTSO *prev = NULL;
2849 for (t = sleeping_queue; t != END_TSO_QUEUE;
2850 prev = t, t = t->link) {
2853 sleeping_queue = t->link;
2855 prev->link = t->link;
2860 barf("unblockThread (delay): TSO not found");
2864 barf("unblockThread");
2868 tso->link = END_TSO_QUEUE;
2869 tso->why_blocked = NotBlocked;
2870 tso->block_info.closure = NULL;
2871 APPEND_TO_RUN_QUEUE(tso);
2875 /* -----------------------------------------------------------------------------
2878 * Check the blackhole_queue for threads that can be woken up. We do
2879 * this periodically: before every GC, and whenever the run queue is
2882 * An elegant solution might be to just wake up all the blocked
2883 * threads with awakenBlockedQueue occasionally: they'll go back to
2884 * sleep again if the object is still a BLACKHOLE. Unfortunately this
2885 * doesn't give us a way to tell whether we've actually managed to
2886 * wake up any threads, so we would be busy-waiting.
2888 * -------------------------------------------------------------------------- */
2891 checkBlackHoles( void )
2894 rtsBool any_woke_up = rtsFalse;
2897 IF_DEBUG(scheduler, sched_belch("checking threads blocked on black holes"));
2899 // ASSUMES: sched_mutex
2900 prev = &blackhole_queue;
2901 t = blackhole_queue;
2902 while (t != END_TSO_QUEUE) {
2903 ASSERT(t->why_blocked == BlockedOnBlackHole);
2904 type = get_itbl(t->block_info.closure)->type;
2905 if (type != BLACKHOLE && type != CAF_BLACKHOLE) {
2906 t = unblockOneLocked(t);
2908 any_woke_up = rtsTrue;
2918 /* -----------------------------------------------------------------------------
2921 * The following function implements the magic for raising an
2922 * asynchronous exception in an existing thread.
2924 * We first remove the thread from any queue on which it might be
2925 * blocked. The possible blockages are MVARs and BLACKHOLE_BQs.
2927 * We strip the stack down to the innermost CATCH_FRAME, building
2928 * thunks in the heap for all the active computations, so they can
2929 * be restarted if necessary. When we reach a CATCH_FRAME, we build
2930 * an application of the handler to the exception, and push it on
2931 * the top of the stack.
2933 * How exactly do we save all the active computations? We create an
2934 * AP_STACK for every UpdateFrame on the stack. Entering one of these
2935 * AP_STACKs pushes everything from the corresponding update frame
2936 * upwards onto the stack. (Actually, it pushes everything up to the
2937 * next update frame plus a pointer to the next AP_STACK object.
2938 * Entering the next AP_STACK object pushes more onto the stack until we
2939 * reach the last AP_STACK object - at which point the stack should look
2940 * exactly as it did when we killed the TSO and we can continue
2941 * execution by entering the closure on top of the stack.
2943 * We can also kill a thread entirely - this happens if either (a) the
2944 * exception passed to raiseAsync is NULL, or (b) there's no
2945 * CATCH_FRAME on the stack. In either case, we strip the entire
2946 * stack and replace the thread with a zombie.
2948 * Locks: sched_mutex held upon entry nor exit.
2950 * -------------------------------------------------------------------------- */
2953 deleteThread(StgTSO *tso)
2955 if (tso->why_blocked != BlockedOnCCall &&
2956 tso->why_blocked != BlockedOnCCall_NoUnblockExc) {
2957 raiseAsync(tso,NULL);
2961 #ifdef FORKPROCESS_PRIMOP_SUPPORTED
2963 deleteThreadImmediately(StgTSO *tso)
2964 { // for forkProcess only:
2965 // delete thread without giving it a chance to catch the KillThread exception
2967 if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) {
2971 if (tso->why_blocked != BlockedOnCCall &&
2972 tso->why_blocked != BlockedOnCCall_NoUnblockExc) {
2976 tso->what_next = ThreadKilled;
2981 raiseAsyncWithLock(StgTSO *tso, StgClosure *exception)
2983 /* When raising async exs from contexts where sched_mutex isn't held;
2984 use raiseAsyncWithLock(). */
2985 ACQUIRE_LOCK(&sched_mutex);
2986 raiseAsync(tso,exception);
2987 RELEASE_LOCK(&sched_mutex);
2991 raiseAsync(StgTSO *tso, StgClosure *exception)
2993 raiseAsync_(tso, exception, rtsFalse);
2997 raiseAsync_(StgTSO *tso, StgClosure *exception, rtsBool stop_at_atomically)
2999 StgRetInfoTable *info;
3002 // Thread already dead?
3003 if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) {
3008 sched_belch("raising exception in thread %ld.", (long)tso->id));
3010 // Remove it from any blocking queues
3015 // The stack freezing code assumes there's a closure pointer on
3016 // the top of the stack, so we have to arrange that this is the case...
3018 if (sp[0] == (W_)&stg_enter_info) {
3022 sp[0] = (W_)&stg_dummy_ret_closure;
3028 // 1. Let the top of the stack be the "current closure"
3030 // 2. Walk up the stack until we find either an UPDATE_FRAME or a
3033 // 3. If it's an UPDATE_FRAME, then make an AP_STACK containing the
3034 // current closure applied to the chunk of stack up to (but not
3035 // including) the update frame. This closure becomes the "current
3036 // closure". Go back to step 2.
3038 // 4. If it's a CATCH_FRAME, then leave the exception handler on
3039 // top of the stack applied to the exception.
3041 // 5. If it's a STOP_FRAME, then kill the thread.
3043 // NB: if we pass an ATOMICALLY_FRAME then abort the associated
3050 info = get_ret_itbl((StgClosure *)frame);
3052 while (info->i.type != UPDATE_FRAME
3053 && (info->i.type != CATCH_FRAME || exception == NULL)
3054 && info->i.type != STOP_FRAME
3055 && (info->i.type != ATOMICALLY_FRAME || stop_at_atomically == rtsFalse))
3057 if (info->i.type == CATCH_RETRY_FRAME || info->i.type == ATOMICALLY_FRAME) {
3058 // IF we find an ATOMICALLY_FRAME then we abort the
3059 // current transaction and propagate the exception. In
3060 // this case (unlike ordinary exceptions) we do not care
3061 // whether the transaction is valid or not because its
3062 // possible validity cannot have caused the exception
3063 // and will not be visible after the abort.
3065 debugBelch("Found atomically block delivering async exception\n"));
3066 stmAbortTransaction(tso -> trec);
3067 tso -> trec = stmGetEnclosingTRec(tso -> trec);
3069 frame += stack_frame_sizeW((StgClosure *)frame);
3070 info = get_ret_itbl((StgClosure *)frame);
3073 switch (info->i.type) {
3075 case ATOMICALLY_FRAME:
3076 ASSERT(stop_at_atomically);
3077 ASSERT(stmGetEnclosingTRec(tso->trec) == NO_TREC);
3078 stmCondemnTransaction(tso -> trec);
3082 // R1 is not a register: the return convention for IO in
3083 // this case puts the return value on the stack, so we
3084 // need to set up the stack to return to the atomically
3085 // frame properly...
3086 tso->sp = frame - 2;
3087 tso->sp[1] = (StgWord) &stg_NO_FINALIZER_closure; // why not?
3088 tso->sp[0] = (StgWord) &stg_ut_1_0_unreg_info;
3090 tso->what_next = ThreadRunGHC;
3094 // If we find a CATCH_FRAME, and we've got an exception to raise,
3095 // then build the THUNK raise(exception), and leave it on
3096 // top of the CATCH_FRAME ready to enter.
3100 StgCatchFrame *cf = (StgCatchFrame *)frame;
3104 // we've got an exception to raise, so let's pass it to the
3105 // handler in this frame.
3107 raise = (StgThunk *)allocate(sizeofW(StgThunk)+1);
3108 TICK_ALLOC_SE_THK(1,0);
3109 SET_HDR(raise,&stg_raise_info,cf->header.prof.ccs);
3110 raise->payload[0] = exception;
3112 // throw away the stack from Sp up to the CATCH_FRAME.
3116 /* Ensure that async excpetions are blocked now, so we don't get
3117 * a surprise exception before we get around to executing the
3120 if (tso->blocked_exceptions == NULL) {
3121 tso->blocked_exceptions = END_TSO_QUEUE;
3124 /* Put the newly-built THUNK on top of the stack, ready to execute
3125 * when the thread restarts.
3128 sp[-1] = (W_)&stg_enter_info;
3130 tso->what_next = ThreadRunGHC;
3131 IF_DEBUG(sanity, checkTSO(tso));
3140 // First build an AP_STACK consisting of the stack chunk above the
3141 // current update frame, with the top word on the stack as the
3144 words = frame - sp - 1;
3145 ap = (StgAP_STACK *)allocate(AP_STACK_sizeW(words));
3148 ap->fun = (StgClosure *)sp[0];
3150 for(i=0; i < (nat)words; ++i) {
3151 ap->payload[i] = (StgClosure *)*sp++;
3154 SET_HDR(ap,&stg_AP_STACK_info,
3155 ((StgClosure *)frame)->header.prof.ccs /* ToDo */);
3156 TICK_ALLOC_UP_THK(words+1,0);
3159 debugBelch("sched: Updating ");
3160 printPtr((P_)((StgUpdateFrame *)frame)->updatee);
3161 debugBelch(" with ");
3162 printObj((StgClosure *)ap);
3165 // Replace the updatee with an indirection - happily
3166 // this will also wake up any threads currently
3167 // waiting on the result.
3169 // Warning: if we're in a loop, more than one update frame on
3170 // the stack may point to the same object. Be careful not to
3171 // overwrite an IND_OLDGEN in this case, because we'll screw
3172 // up the mutable lists. To be on the safe side, don't
3173 // overwrite any kind of indirection at all. See also
3174 // threadSqueezeStack in GC.c, where we have to make a similar
3177 if (!closure_IND(((StgUpdateFrame *)frame)->updatee)) {
3178 // revert the black hole
3179 UPD_IND_NOLOCK(((StgUpdateFrame *)frame)->updatee,
3182 sp += sizeofW(StgUpdateFrame) - 1;
3183 sp[0] = (W_)ap; // push onto stack
3188 // We've stripped the entire stack, the thread is now dead.
3189 sp += sizeofW(StgStopFrame);
3190 tso->what_next = ThreadKilled;
3201 /* -----------------------------------------------------------------------------
3202 raiseExceptionHelper
3204 This function is called by the raise# primitve, just so that we can
3205 move some of the tricky bits of raising an exception from C-- into
3206 C. Who knows, it might be a useful re-useable thing here too.
3207 -------------------------------------------------------------------------- */
3210 raiseExceptionHelper (StgTSO *tso, StgClosure *exception)
3212 StgThunk *raise_closure = NULL;
3214 StgRetInfoTable *info;
3216 // This closure represents the expression 'raise# E' where E
3217 // is the exception raise. It is used to overwrite all the
3218 // thunks which are currently under evaluataion.
3222 // LDV profiling: stg_raise_info has THUNK as its closure
3223 // type. Since a THUNK takes at least MIN_UPD_SIZE words in its
3224 // payload, MIN_UPD_SIZE is more approprate than 1. It seems that
3225 // 1 does not cause any problem unless profiling is performed.
3226 // However, when LDV profiling goes on, we need to linearly scan
3227 // small object pool, where raise_closure is stored, so we should
3228 // use MIN_UPD_SIZE.
3230 // raise_closure = (StgClosure *)RET_STGCALL1(P_,allocate,
3231 // sizeofW(StgClosure)+1);
3235 // Walk up the stack, looking for the catch frame. On the way,
3236 // we update any closures pointed to from update frames with the
3237 // raise closure that we just built.
3241 info = get_ret_itbl((StgClosure *)p);
3242 next = p + stack_frame_sizeW((StgClosure *)p);
3243 switch (info->i.type) {
3246 // Only create raise_closure if we need to.
3247 if (raise_closure == NULL) {
3249 (StgThunk *)allocate(sizeofW(StgThunk)+MIN_UPD_SIZE);
3250 SET_HDR(raise_closure, &stg_raise_info, CCCS);
3251 raise_closure->payload[0] = exception;
3253 UPD_IND(((StgUpdateFrame *)p)->updatee,(StgClosure *)raise_closure);
3257 case ATOMICALLY_FRAME:
3258 IF_DEBUG(stm, debugBelch("Found ATOMICALLY_FRAME at %p\n", p));
3260 return ATOMICALLY_FRAME;
3266 case CATCH_STM_FRAME:
3267 IF_DEBUG(stm, debugBelch("Found CATCH_STM_FRAME at %p\n", p));
3269 return CATCH_STM_FRAME;
3275 case CATCH_RETRY_FRAME:
3284 /* -----------------------------------------------------------------------------
3285 findRetryFrameHelper
3287 This function is called by the retry# primitive. It traverses the stack
3288 leaving tso->sp referring to the frame which should handle the retry.
3290 This should either be a CATCH_RETRY_FRAME (if the retry# is within an orElse#)
3291 or should be a ATOMICALLY_FRAME (if the retry# reaches the top level).
3293 We skip CATCH_STM_FRAMEs because retries are not considered to be exceptions,
3294 despite the similar implementation.
3296 We should not expect to see CATCH_FRAME or STOP_FRAME because those should
3297 not be created within memory transactions.
3298 -------------------------------------------------------------------------- */
3301 findRetryFrameHelper (StgTSO *tso)
3304 StgRetInfoTable *info;
3308 info = get_ret_itbl((StgClosure *)p);
3309 next = p + stack_frame_sizeW((StgClosure *)p);
3310 switch (info->i.type) {
3312 case ATOMICALLY_FRAME:
3313 IF_DEBUG(stm, debugBelch("Found ATOMICALLY_FRAME at %p during retrry\n", p));
3315 return ATOMICALLY_FRAME;
3317 case CATCH_RETRY_FRAME:
3318 IF_DEBUG(stm, debugBelch("Found CATCH_RETRY_FRAME at %p during retrry\n", p));
3320 return CATCH_RETRY_FRAME;
3322 case CATCH_STM_FRAME:
3324 ASSERT(info->i.type != CATCH_FRAME);
3325 ASSERT(info->i.type != STOP_FRAME);
3332 /* -----------------------------------------------------------------------------
3333 resurrectThreads is called after garbage collection on the list of
3334 threads found to be garbage. Each of these threads will be woken
3335 up and sent a signal: BlockedOnDeadMVar if the thread was blocked
3336 on an MVar, or NonTermination if the thread was blocked on a Black
3339 Locks: sched_mutex isn't held upon entry nor exit.
3340 -------------------------------------------------------------------------- */
3343 resurrectThreads( StgTSO *threads )
3347 for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
3348 next = tso->global_link;
3349 tso->global_link = all_threads;
3351 IF_DEBUG(scheduler, sched_belch("resurrecting thread %d", tso->id));
3353 switch (tso->why_blocked) {
3355 case BlockedOnException:
3356 /* Called by GC - sched_mutex lock is currently held. */
3357 raiseAsync(tso,(StgClosure *)BlockedOnDeadMVar_closure);
3359 case BlockedOnBlackHole:
3360 raiseAsync(tso,(StgClosure *)NonTermination_closure);
3363 raiseAsync(tso,(StgClosure *)BlockedIndefinitely_closure);
3366 /* This might happen if the thread was blocked on a black hole
3367 * belonging to a thread that we've just woken up (raiseAsync
3368 * can wake up threads, remember...).
3372 barf("resurrectThreads: thread blocked in a strange way");
3377 /* ----------------------------------------------------------------------------
3378 * Debugging: why is a thread blocked
3379 * [Also provides useful information when debugging threaded programs
3380 * at the Haskell source code level, so enable outside of DEBUG. --sof 7/02]
3381 ------------------------------------------------------------------------- */
3384 printThreadBlockage(StgTSO *tso)
3386 switch (tso->why_blocked) {
3388 debugBelch("is blocked on read from fd %d", (int)(tso->block_info.fd));
3390 case BlockedOnWrite:
3391 debugBelch("is blocked on write to fd %d", (int)(tso->block_info.fd));
3393 #if defined(mingw32_HOST_OS)
3394 case BlockedOnDoProc:
3395 debugBelch("is blocked on proc (request: %ld)", tso->block_info.async_result->reqID);
3398 case BlockedOnDelay:
3399 debugBelch("is blocked until %ld", (long)(tso->block_info.target));
3402 debugBelch("is blocked on an MVar @ %p", tso->block_info.closure);
3404 case BlockedOnException:
3405 debugBelch("is blocked on delivering an exception to thread %d",
3406 tso->block_info.tso->id);
3408 case BlockedOnBlackHole:
3409 debugBelch("is blocked on a black hole");
3412 debugBelch("is not blocked");
3414 #if defined(PARALLEL_HASKELL)
3416 debugBelch("is blocked on global address; local FM_BQ is %p (%s)",
3417 tso->block_info.closure, info_type(tso->block_info.closure));
3419 case BlockedOnGA_NoSend:
3420 debugBelch("is blocked on global address (no send); local FM_BQ is %p (%s)",
3421 tso->block_info.closure, info_type(tso->block_info.closure));
3424 case BlockedOnCCall:
3425 debugBelch("is blocked on an external call");
3427 case BlockedOnCCall_NoUnblockExc:
3428 debugBelch("is blocked on an external call (exceptions were already blocked)");
3431 debugBelch("is blocked on an STM operation");
3434 barf("printThreadBlockage: strange tso->why_blocked: %d for TSO %d (%d)",
3435 tso->why_blocked, tso->id, tso);
3440 printThreadStatus(StgTSO *tso)
3442 switch (tso->what_next) {
3446 /* should cover all closures that may have a blocking queue */
3447 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3448 get_itbl(node)->type == FETCH_ME_BQ ||
3449 get_itbl(node)->type == RBH);
3451 ASSERT(node!=(StgClosure*)NULL); // sanity check
3452 node_loc = where_is(node);
3454 debugBelch("## BQ of closure %p (%s) on [PE %d]: ",
3455 node, info_type(node), node_loc);
3458 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3460 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
3461 !end; // iterate until bqe points to a CONSTR
3462 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
3463 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3464 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
3465 /* types of closures that may appear in a blocking queue */
3466 ASSERT(get_itbl(bqe)->type == TSO ||
3467 get_itbl(bqe)->type == CONSTR);
3468 /* only BQs of an RBH end with an RBH_Save closure */
3469 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3471 tso_loc = where_is((StgClosure *)bqe);
3472 switch (get_itbl(bqe)->type) {
3474 debugBelch(" TSO %d (%p) on [PE %d],",
3475 ((StgTSO *)bqe)->id, (StgTSO *)bqe, tso_loc);
3478 debugBelch(" %s (IP %p),",
3479 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3480 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3481 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3482 "RBH_Save_?"), get_itbl(bqe));
3485 barf("Unexpected closure type %s in blocking queue of %p (%s)",
3486 info_type((StgClosure *)bqe), node, info_type(node));
3494 #if defined(PARALLEL_HASKELL)
3501 for (i=0, tso=run_queue_hd;
3502 tso != END_TSO_QUEUE;
3511 sched_belch(char *s, ...)
3515 #ifdef RTS_SUPPORTS_THREADS
3516 debugBelch("sched (task %p): ", osThreadId());
3517 #elif defined(PARALLEL_HASKELL)
3520 debugBelch("sched: ");