1 /* ---------------------------------------------------------------------------
2 * $Id: Schedule.c,v 1.158 2002/12/10 13:38:40 wolfgang Exp $
4 * (c) The GHC Team, 1998-2000
8 * Different GHC ways use this scheduler quite differently (see comments below)
9 * Here is the global picture:
11 * WAY Name CPP flag What's it for
12 * --------------------------------------
13 * mp GUM PAR Parallel execution on a distributed memory machine
14 * s SMP SMP Parallel execution on a shared memory machine
15 * mg GranSim GRAN Simulation of parallel execution
16 * md GUM/GdH DIST Distributed execution (based on GUM)
18 * --------------------------------------------------------------------------*/
20 //@node Main scheduling code, , ,
21 //@section Main scheduling code
24 * Version with scheduler monitor support for SMPs (WAY=s):
26 This design provides a high-level API to create and schedule threads etc.
27 as documented in the SMP design document.
29 It uses a monitor design controlled by a single mutex to exercise control
30 over accesses to shared data structures, and builds on the Posix threads
33 The majority of state is shared. In order to keep essential per-task state,
34 there is a Capability structure, which contains all the information
35 needed to run a thread: its STG registers, a pointer to its TSO, a
36 nursery etc. During STG execution, a pointer to the capability is
37 kept in a register (BaseReg).
39 In a non-SMP build, there is one global capability, namely MainRegTable.
43 * Version with support for distributed memory parallelism aka GUM (WAY=mp):
45 The main scheduling loop in GUM iterates until a finish message is received.
46 In that case a global flag @receivedFinish@ is set and this instance of
47 the RTS shuts down. See ghc/rts/parallel/HLComms.c:processMessages()
48 for the handling of incoming messages, such as PP_FINISH.
49 Note that in the parallel case we have a system manager that coordinates
50 different PEs, each of which are running one instance of the RTS.
51 See ghc/rts/parallel/SysMan.c for the main routine of the parallel program.
52 From this routine processes executing ghc/rts/Main.c are spawned. -- HWL
54 * Version with support for simulating parallel execution aka GranSim (WAY=mg):
56 The main scheduling code in GranSim is quite different from that in std
57 (concurrent) Haskell: while concurrent Haskell just iterates over the
58 threads in the runnable queue, GranSim is event driven, i.e. it iterates
59 over the events in the global event queue. -- HWL
64 //* Variables and Data structures::
65 //* Main scheduling loop::
66 //* Suspend and Resume::
68 //* Garbage Collextion Routines::
69 //* Blocking Queue Routines::
70 //* Exception Handling Routines::
71 //* Debugging Routines::
75 //@node Includes, Variables and Data structures, Main scheduling code, Main scheduling code
76 //@subsection Includes
78 #include "PosixSource.h"
85 #include "StgStartup.h"
87 #define COMPILING_SCHEDULER
89 #include "StgMiscClosures.h"
91 #include "Interpreter.h"
92 #include "Exception.h"
100 #include "ThreadLabels.h"
102 #include "Proftimer.h"
103 #include "ProfHeap.h"
105 #if defined(GRAN) || defined(PAR)
106 # include "GranSimRts.h"
107 # include "GranSim.h"
108 # include "ParallelRts.h"
109 # include "Parallel.h"
110 # include "ParallelDebug.h"
111 # include "FetchMe.h"
115 #include "Capability.h"
116 #include "OSThreads.h"
119 #ifdef HAVE_SYS_TYPES_H
120 #include <sys/types.h>
130 //@node Variables and Data structures, Prototypes, Includes, Main scheduling code
131 //@subsection Variables and Data structures
133 /* Main thread queue.
134 * Locks required: sched_mutex.
136 StgMainThread *main_threads = NULL;
139 * Locks required: sched_mutex.
143 StgTSO* ActiveTSO = NULL; /* for assigning system costs; GranSim-Light only */
144 /* rtsTime TimeOfNextEvent, EndOfTimeSlice; now in GranSim.c */
147 In GranSim we have a runnable and a blocked queue for each processor.
148 In order to minimise code changes new arrays run_queue_hds/tls
149 are created. run_queue_hd is then a short cut (macro) for
150 run_queue_hds[CurrentProc] (see GranSim.h).
153 StgTSO *run_queue_hds[MAX_PROC], *run_queue_tls[MAX_PROC];
154 StgTSO *blocked_queue_hds[MAX_PROC], *blocked_queue_tls[MAX_PROC];
155 StgTSO *ccalling_threadss[MAX_PROC];
156 /* We use the same global list of threads (all_threads) in GranSim as in
157 the std RTS (i.e. we are cheating). However, we don't use this list in
158 the GranSim specific code at the moment (so we are only potentially
163 StgTSO *run_queue_hd = NULL;
164 StgTSO *run_queue_tl = NULL;
165 StgTSO *blocked_queue_hd = NULL;
166 StgTSO *blocked_queue_tl = NULL;
167 StgTSO *sleeping_queue = NULL; /* perhaps replace with a hash table? */
171 /* Linked list of all threads.
172 * Used for detecting garbage collected threads.
174 StgTSO *all_threads = NULL;
176 /* When a thread performs a safe C call (_ccall_GC, using old
177 * terminology), it gets put on the suspended_ccalling_threads
178 * list. Used by the garbage collector.
180 static StgTSO *suspended_ccalling_threads;
182 static StgTSO *threadStackOverflow(StgTSO *tso);
184 /* KH: The following two flags are shared memory locations. There is no need
185 to lock them, since they are only unset at the end of a scheduler
189 /* flag set by signal handler to precipitate a context switch */
190 //@cindex context_switch
191 nat context_switch = 0;
193 /* if this flag is set as well, give up execution */
194 //@cindex interrupted
195 rtsBool interrupted = rtsFalse;
197 /* Next thread ID to allocate.
198 * Locks required: thread_id_mutex
200 //@cindex next_thread_id
201 static StgThreadID next_thread_id = 1;
204 * Pointers to the state of the current thread.
205 * Rule of thumb: if CurrentTSO != NULL, then we're running a Haskell
206 * thread. If CurrentTSO == NULL, then we're at the scheduler level.
209 /* The smallest stack size that makes any sense is:
210 * RESERVED_STACK_WORDS (so we can get back from the stack overflow)
211 * + sizeofW(StgStopFrame) (the stg_stop_thread_info frame)
212 * + 1 (the realworld token for an IO thread)
213 * + 1 (the closure to enter)
215 * A thread with this stack will bomb immediately with a stack
216 * overflow, which will increase its stack size.
219 #define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 2)
226 /* This is used in `TSO.h' and gcc 2.96 insists that this variable actually
227 * exists - earlier gccs apparently didn't.
232 static rtsBool ready_to_gc;
235 * Set to TRUE when entering a shutdown state (via shutdownHaskellAndExit()) --
236 * in an MT setting, needed to signal that a worker thread shouldn't hang around
237 * in the scheduler when it is out of work.
239 static rtsBool shutting_down_scheduler = rtsFalse;
241 void addToBlockedQueue ( StgTSO *tso );
243 static void schedule ( void );
244 void interruptStgRts ( void );
246 static void detectBlackHoles ( void );
249 static void sched_belch(char *s, ...);
252 #if defined(RTS_SUPPORTS_THREADS)
253 /* ToDo: carefully document the invariants that go together
254 * with these synchronisation objects.
256 Mutex sched_mutex = INIT_MUTEX_VAR;
257 Mutex term_mutex = INIT_MUTEX_VAR;
260 * A heavyweight solution to the problem of protecting
261 * the thread_id from concurrent update.
263 Mutex thread_id_mutex = INIT_MUTEX_VAR;
267 static Condition gc_pending_cond = INIT_COND_VAR;
271 #endif /* RTS_SUPPORTS_THREADS */
275 rtsTime TimeOfLastYield;
276 rtsBool emitSchedule = rtsTrue;
280 static char *whatNext_strs[] = {
290 StgTSO * createSparkThread(rtsSpark spark);
291 StgTSO * activateSpark (rtsSpark spark);
295 * The thread state for the main thread.
296 // ToDo: check whether not needed any more
300 #if defined(PAR) || defined(RTS_SUPPORTS_THREADS)
301 static void taskStart(void);
312 //@node Main scheduling loop, Suspend and Resume, Prototypes, Main scheduling code
313 //@subsection Main scheduling loop
315 /* ---------------------------------------------------------------------------
316 Main scheduling loop.
318 We use round-robin scheduling, each thread returning to the
319 scheduler loop when one of these conditions is detected:
322 * timer expires (thread yields)
327 Locking notes: we acquire the scheduler lock once at the beginning
328 of the scheduler loop, and release it when
330 * running a thread, or
331 * waiting for work, or
332 * waiting for a GC to complete.
335 In a GranSim setup this loop iterates over the global event queue.
336 This revolves around the global event queue, which determines what
337 to do next. Therefore, it's more complicated than either the
338 concurrent or the parallel (GUM) setup.
341 GUM iterates over incoming messages.
342 It starts with nothing to do (thus CurrentTSO == END_TSO_QUEUE),
343 and sends out a fish whenever it has nothing to do; in-between
344 doing the actual reductions (shared code below) it processes the
345 incoming messages and deals with delayed operations
346 (see PendingFetches).
347 This is not the ugliest code you could imagine, but it's bloody close.
349 ------------------------------------------------------------------------ */
356 StgThreadReturnCode ret;
364 rtsBool receivedFinish = rtsFalse;
366 nat tp_size, sp_size; // stats only
369 rtsBool was_interrupted = rtsFalse;
371 ACQUIRE_LOCK(&sched_mutex);
373 #if defined(RTS_SUPPORTS_THREADS)
374 waitForWorkCapability(&sched_mutex, &cap, rtsFalse);
376 /* simply initialise it in the non-threaded case */
377 grabCapability(&cap);
381 /* set up first event to get things going */
382 /* ToDo: assign costs for system setup and init MainTSO ! */
383 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
385 CurrentTSO, (StgClosure*)NULL, (rtsSpark*)NULL);
388 fprintf(stderr, "GRAN: Init CurrentTSO (in schedule) = %p\n", CurrentTSO);
389 G_TSO(CurrentTSO, 5));
391 if (RtsFlags.GranFlags.Light) {
392 /* Save current time; GranSim Light only */
393 CurrentTSO->gran.clock = CurrentTime[CurrentProc];
396 event = get_next_event();
398 while (event!=(rtsEvent*)NULL) {
399 /* Choose the processor with the next event */
400 CurrentProc = event->proc;
401 CurrentTSO = event->tso;
405 while (!receivedFinish) { /* set by processMessages */
406 /* when receiving PP_FINISH message */
413 IF_DEBUG(scheduler, printAllThreads());
415 #if defined(RTS_SUPPORTS_THREADS)
416 /* Check to see whether there are any worker threads
417 waiting to deposit external call results. If so,
418 yield our capability */
419 yieldToReturningWorker(&sched_mutex, &cap);
422 /* If we're interrupted (the user pressed ^C, or some other
423 * termination condition occurred), kill all the currently running
427 IF_DEBUG(scheduler, sched_belch("interrupted"));
429 interrupted = rtsFalse;
430 was_interrupted = rtsTrue;
433 /* Go through the list of main threads and wake up any
434 * clients whose computations have finished. ToDo: this
435 * should be done more efficiently without a linear scan
436 * of the main threads list, somehow...
438 #if defined(RTS_SUPPORTS_THREADS)
440 StgMainThread *m, **prev;
441 prev = &main_threads;
442 for (m = main_threads; m != NULL; m = m->link) {
443 switch (m->tso->what_next) {
446 *(m->ret) = (StgClosure *)m->tso->sp[0];
450 broadcastCondition(&m->wakeup);
452 removeThreadLabel((StgWord)m->tso);
456 if (m->ret) *(m->ret) = NULL;
458 if (was_interrupted) {
459 m->stat = Interrupted;
463 broadcastCondition(&m->wakeup);
465 removeThreadLabel((StgWord)m->tso);
474 #else /* not threaded */
477 /* in GUM do this only on the Main PE */
480 /* If our main thread has finished or been killed, return.
483 StgMainThread *m = main_threads;
484 if (m->tso->what_next == ThreadComplete
485 || m->tso->what_next == ThreadKilled) {
487 removeThreadLabel((StgWord)m->tso);
489 main_threads = main_threads->link;
490 if (m->tso->what_next == ThreadComplete) {
491 /* we finished successfully, fill in the return value */
492 if (m->ret) { *(m->ret) = (StgClosure *)m->tso->sp[0]; };
496 if (m->ret) { *(m->ret) = NULL; };
497 if (was_interrupted) {
498 m->stat = Interrupted;
508 /* Top up the run queue from our spark pool. We try to make the
509 * number of threads in the run queue equal to the number of
512 * Disable spark support in SMP for now, non-essential & requires
513 * a little bit of work to make it compile cleanly. -- sof 1/02.
515 #if 0 /* defined(SMP) */
517 nat n = getFreeCapabilities();
518 StgTSO *tso = run_queue_hd;
520 /* Count the run queue */
521 while (n > 0 && tso != END_TSO_QUEUE) {
528 spark = findSpark(rtsFalse);
530 break; /* no more sparks in the pool */
532 /* I'd prefer this to be done in activateSpark -- HWL */
533 /* tricky - it needs to hold the scheduler lock and
534 * not try to re-acquire it -- SDM */
535 createSparkThread(spark);
537 sched_belch("==^^ turning spark of closure %p into a thread",
538 (StgClosure *)spark));
541 /* We need to wake up the other tasks if we just created some
544 if (getFreeCapabilities() - n > 1) {
545 signalCondition( &thread_ready_cond );
550 /* check for signals each time around the scheduler */
551 #ifndef mingw32_TARGET_OS
552 if (signals_pending()) {
553 RELEASE_LOCK(&sched_mutex); /* ToDo: kill */
554 startSignalHandlers();
555 ACQUIRE_LOCK(&sched_mutex);
559 /* Check whether any waiting threads need to be woken up. If the
560 * run queue is empty, and there are no other tasks running, we
561 * can wait indefinitely for something to happen.
562 * ToDo: what if another client comes along & requests another
565 if ( !EMPTY_QUEUE(blocked_queue_hd) || !EMPTY_QUEUE(sleeping_queue) ) {
566 awaitEvent( EMPTY_RUN_QUEUE()
568 && allFreeCapabilities()
572 /* we can be interrupted while waiting for I/O... */
573 if (interrupted) continue;
576 * Detect deadlock: when we have no threads to run, there are no
577 * threads waiting on I/O or sleeping, and all the other tasks are
578 * waiting for work, we must have a deadlock of some description.
580 * We first try to find threads blocked on themselves (ie. black
581 * holes), and generate NonTermination exceptions where necessary.
583 * If no threads are black holed, we have a deadlock situation, so
584 * inform all the main threads.
587 if ( EMPTY_THREAD_QUEUES()
588 #if defined(RTS_SUPPORTS_THREADS)
589 && EMPTY_QUEUE(suspended_ccalling_threads)
592 && allFreeCapabilities()
596 IF_DEBUG(scheduler, sched_belch("deadlocked, forcing major GC..."));
597 #if defined(THREADED_RTS)
598 /* and SMP mode ..? */
599 releaseCapability(cap);
601 // Garbage collection can release some new threads due to
602 // either (a) finalizers or (b) threads resurrected because
603 // they are about to be send BlockedOnDeadMVar. Any threads
604 // thus released will be immediately runnable.
605 GarbageCollect(GetRoots,rtsTrue);
607 if ( !EMPTY_RUN_QUEUE() ) { goto not_deadlocked; }
610 sched_belch("still deadlocked, checking for black holes..."));
613 if ( !EMPTY_RUN_QUEUE() ) { goto not_deadlocked; }
615 #ifndef mingw32_TARGET_OS
616 /* If we have user-installed signal handlers, then wait
617 * for signals to arrive rather then bombing out with a
620 #if defined(RTS_SUPPORTS_THREADS)
621 if ( 0 ) { /* hmm..what to do? Simply stop waiting for
622 a signal with no runnable threads (or I/O
623 suspended ones) leads nowhere quick.
624 For now, simply shut down when we reach this
627 ToDo: define precisely under what conditions
628 the Scheduler should shut down in an MT setting.
631 if ( anyUserHandlers() ) {
634 sched_belch("still deadlocked, waiting for signals..."));
638 // we might be interrupted...
639 if (interrupted) { continue; }
641 if (signals_pending()) {
642 RELEASE_LOCK(&sched_mutex);
643 startSignalHandlers();
644 ACQUIRE_LOCK(&sched_mutex);
646 ASSERT(!EMPTY_RUN_QUEUE());
651 /* Probably a real deadlock. Send the current main thread the
652 * Deadlock exception (or in the SMP build, send *all* main
653 * threads the deadlock exception, since none of them can make
658 #if defined(RTS_SUPPORTS_THREADS)
659 for (m = main_threads; m != NULL; m = m->link) {
660 switch (m->tso->why_blocked) {
661 case BlockedOnBlackHole:
662 raiseAsync(m->tso, (StgClosure *)NonTermination_closure);
664 case BlockedOnException:
666 raiseAsync(m->tso, (StgClosure *)Deadlock_closure);
669 barf("deadlock: main thread blocked in a strange way");
674 switch (m->tso->why_blocked) {
675 case BlockedOnBlackHole:
676 raiseAsync(m->tso, (StgClosure *)NonTermination_closure);
678 case BlockedOnException:
680 raiseAsync(m->tso, (StgClosure *)Deadlock_closure);
683 barf("deadlock: main thread blocked in a strange way");
688 #if defined(RTS_SUPPORTS_THREADS)
689 /* ToDo: revisit conditions (and mechanism) for shutting
690 down a multi-threaded world */
691 IF_DEBUG(scheduler, sched_belch("all done, i think...shutting down."));
692 RELEASE_LOCK(&sched_mutex);
700 /* ToDo: add deadlock detection in GUM (similar to SMP) -- HWL */
704 /* If there's a GC pending, don't do anything until it has
708 IF_DEBUG(scheduler,sched_belch("waiting for GC"));
709 waitCondition( &gc_pending_cond, &sched_mutex );
713 #if defined(RTS_SUPPORTS_THREADS)
714 /* block until we've got a thread on the run queue and a free
718 if ( EMPTY_RUN_QUEUE() ) {
719 /* Give up our capability */
720 releaseCapability(cap);
722 /* If we're in the process of shutting down (& running the
723 * a batch of finalisers), don't wait around.
725 if ( shutting_down_scheduler ) {
726 RELEASE_LOCK(&sched_mutex);
729 IF_DEBUG(scheduler, sched_belch("thread %d: waiting for work", osThreadId()));
730 waitForWorkCapability(&sched_mutex, &cap, rtsTrue);
731 IF_DEBUG(scheduler, sched_belch("thread %d: work now available", osThreadId()));
736 if (RtsFlags.GranFlags.Light)
737 GranSimLight_enter_system(event, &ActiveTSO); // adjust ActiveTSO etc
739 /* adjust time based on time-stamp */
740 if (event->time > CurrentTime[CurrentProc] &&
741 event->evttype != ContinueThread)
742 CurrentTime[CurrentProc] = event->time;
744 /* Deal with the idle PEs (may issue FindWork or MoveSpark events) */
745 if (!RtsFlags.GranFlags.Light)
748 IF_DEBUG(gran, fprintf(stderr, "GRAN: switch by event-type\n"));
750 /* main event dispatcher in GranSim */
751 switch (event->evttype) {
752 /* Should just be continuing execution */
754 IF_DEBUG(gran, fprintf(stderr, "GRAN: doing ContinueThread\n"));
755 /* ToDo: check assertion
756 ASSERT(run_queue_hd != (StgTSO*)NULL &&
757 run_queue_hd != END_TSO_QUEUE);
759 /* Ignore ContinueThreads for fetching threads (if synchr comm) */
760 if (!RtsFlags.GranFlags.DoAsyncFetch &&
761 procStatus[CurrentProc]==Fetching) {
762 belch("ghuH: Spurious ContinueThread while Fetching ignored; TSO %d (%p) [PE %d]",
763 CurrentTSO->id, CurrentTSO, CurrentProc);
766 /* Ignore ContinueThreads for completed threads */
767 if (CurrentTSO->what_next == ThreadComplete) {
768 belch("ghuH: found a ContinueThread event for completed thread %d (%p) [PE %d] (ignoring ContinueThread)",
769 CurrentTSO->id, CurrentTSO, CurrentProc);
772 /* Ignore ContinueThreads for threads that are being migrated */
773 if (PROCS(CurrentTSO)==Nowhere) {
774 belch("ghuH: trying to run the migrating TSO %d (%p) [PE %d] (ignoring ContinueThread)",
775 CurrentTSO->id, CurrentTSO, CurrentProc);
778 /* The thread should be at the beginning of the run queue */
779 if (CurrentTSO!=run_queue_hds[CurrentProc]) {
780 belch("ghuH: TSO %d (%p) [PE %d] is not at the start of the run_queue when doing a ContinueThread",
781 CurrentTSO->id, CurrentTSO, CurrentProc);
782 break; // run the thread anyway
785 new_event(proc, proc, CurrentTime[proc],
787 (StgTSO*)NULL, (StgClosure*)NULL, (rtsSpark*)NULL);
789 */ /* Catches superfluous CONTINUEs -- should be unnecessary */
790 break; // now actually run the thread; DaH Qu'vam yImuHbej
793 do_the_fetchnode(event);
794 goto next_thread; /* handle next event in event queue */
797 do_the_globalblock(event);
798 goto next_thread; /* handle next event in event queue */
801 do_the_fetchreply(event);
802 goto next_thread; /* handle next event in event queue */
804 case UnblockThread: /* Move from the blocked queue to the tail of */
805 do_the_unblock(event);
806 goto next_thread; /* handle next event in event queue */
808 case ResumeThread: /* Move from the blocked queue to the tail of */
809 /* the runnable queue ( i.e. Qu' SImqa'lu') */
810 event->tso->gran.blocktime +=
811 CurrentTime[CurrentProc] - event->tso->gran.blockedat;
812 do_the_startthread(event);
813 goto next_thread; /* handle next event in event queue */
816 do_the_startthread(event);
817 goto next_thread; /* handle next event in event queue */
820 do_the_movethread(event);
821 goto next_thread; /* handle next event in event queue */
824 do_the_movespark(event);
825 goto next_thread; /* handle next event in event queue */
828 do_the_findwork(event);
829 goto next_thread; /* handle next event in event queue */
832 barf("Illegal event type %u\n", event->evttype);
835 /* This point was scheduler_loop in the old RTS */
837 IF_DEBUG(gran, belch("GRAN: after main switch"));
839 TimeOfLastEvent = CurrentTime[CurrentProc];
840 TimeOfNextEvent = get_time_of_next_event();
841 IgnoreEvents=(TimeOfNextEvent==0); // HWL HACK
842 // CurrentTSO = ThreadQueueHd;
844 IF_DEBUG(gran, belch("GRAN: time of next event is: %ld",
847 if (RtsFlags.GranFlags.Light)
848 GranSimLight_leave_system(event, &ActiveTSO);
850 EndOfTimeSlice = CurrentTime[CurrentProc]+RtsFlags.GranFlags.time_slice;
853 belch("GRAN: end of time-slice is %#lx", EndOfTimeSlice));
855 /* in a GranSim setup the TSO stays on the run queue */
857 /* Take a thread from the run queue. */
858 t = POP_RUN_QUEUE(); // take_off_run_queue(t);
861 fprintf(stderr, "GRAN: About to run current thread, which is\n");
864 context_switch = 0; // turned on via GranYield, checking events and time slice
867 DumpGranEvent(GR_SCHEDULE, t));
869 procStatus[CurrentProc] = Busy;
872 if (PendingFetches != END_BF_QUEUE) {
876 /* ToDo: phps merge with spark activation above */
877 /* check whether we have local work and send requests if we have none */
878 if (EMPTY_RUN_QUEUE()) { /* no runnable threads */
879 /* :-[ no local threads => look out for local sparks */
880 /* the spark pool for the current PE */
881 pool = &(MainRegTable.rSparks); // generalise to cap = &MainRegTable
882 if (advisory_thread_count < RtsFlags.ParFlags.maxThreads &&
883 pool->hd < pool->tl) {
885 * ToDo: add GC code check that we really have enough heap afterwards!!
887 * If we're here (no runnable threads) and we have pending
888 * sparks, we must have a space problem. Get enough space
889 * to turn one of those pending sparks into a
893 spark = findSpark(rtsFalse); /* get a spark */
894 if (spark != (rtsSpark) NULL) {
895 tso = activateSpark(spark); /* turn the spark into a thread */
896 IF_PAR_DEBUG(schedule,
897 belch("==== schedule: Created TSO %d (%p); %d threads active",
898 tso->id, tso, advisory_thread_count));
900 if (tso==END_TSO_QUEUE) { /* failed to activate spark->back to loop */
901 belch("==^^ failed to activate spark");
903 } /* otherwise fall through & pick-up new tso */
905 IF_PAR_DEBUG(verbose,
906 belch("==^^ no local sparks (spark pool contains only NFs: %d)",
907 spark_queue_len(pool)));
912 /* If we still have no work we need to send a FISH to get a spark
915 if (EMPTY_RUN_QUEUE()) {
916 /* =8-[ no local sparks => look for work on other PEs */
918 * We really have absolutely no work. Send out a fish
919 * (there may be some out there already), and wait for
920 * something to arrive. We clearly can't run any threads
921 * until a SCHEDULE or RESUME arrives, and so that's what
922 * we're hoping to see. (Of course, we still have to
923 * respond to other types of messages.)
925 TIME now = msTime() /*CURRENT_TIME*/;
926 IF_PAR_DEBUG(verbose,
927 belch("-- now=%ld", now));
928 IF_PAR_DEBUG(verbose,
929 if (outstandingFishes < RtsFlags.ParFlags.maxFishes &&
930 (last_fish_arrived_at!=0 &&
931 last_fish_arrived_at+RtsFlags.ParFlags.fishDelay > now)) {
932 belch("--$$ delaying FISH until %ld (last fish %ld, delay %ld, now %ld)",
933 last_fish_arrived_at+RtsFlags.ParFlags.fishDelay,
934 last_fish_arrived_at,
935 RtsFlags.ParFlags.fishDelay, now);
938 if (outstandingFishes < RtsFlags.ParFlags.maxFishes &&
939 (last_fish_arrived_at==0 ||
940 (last_fish_arrived_at+RtsFlags.ParFlags.fishDelay <= now))) {
941 /* outstandingFishes is set in sendFish, processFish;
942 avoid flooding system with fishes via delay */
944 sendFish(pe, mytid, NEW_FISH_AGE, NEW_FISH_HISTORY,
947 // Global statistics: count no. of fishes
948 if (RtsFlags.ParFlags.ParStats.Global &&
949 RtsFlags.GcFlags.giveStats > NO_GC_STATS) {
950 globalParStats.tot_fish_mess++;
954 receivedFinish = processMessages();
957 } else if (PacketsWaiting()) { /* Look for incoming messages */
958 receivedFinish = processMessages();
961 /* Now we are sure that we have some work available */
962 ASSERT(run_queue_hd != END_TSO_QUEUE);
964 /* Take a thread from the run queue, if we have work */
965 t = POP_RUN_QUEUE(); // take_off_run_queue(END_TSO_QUEUE);
966 IF_DEBUG(sanity,checkTSO(t));
968 /* ToDo: write something to the log-file
969 if (RTSflags.ParFlags.granSimStats && !sameThread)
970 DumpGranEvent(GR_SCHEDULE, RunnableThreadsHd);
974 /* the spark pool for the current PE */
975 pool = &(MainRegTable.rSparks); // generalise to cap = &MainRegTable
978 belch("--=^ %d threads, %d sparks on [%#x]",
979 run_queue_len(), spark_queue_len(pool), CURRENT_PROC));
982 if (0 && RtsFlags.ParFlags.ParStats.Full &&
983 t && LastTSO && t->id != LastTSO->id &&
984 LastTSO->why_blocked == NotBlocked &&
985 LastTSO->what_next != ThreadComplete) {
986 // if previously scheduled TSO not blocked we have to record the context switch
987 DumpVeryRawGranEvent(TimeOfLastYield, CURRENT_PROC, CURRENT_PROC,
988 GR_DESCHEDULE, LastTSO, (StgClosure *)NULL, 0, 0);
991 if (RtsFlags.ParFlags.ParStats.Full &&
992 (emitSchedule /* forced emit */ ||
993 (t && LastTSO && t->id != LastTSO->id))) {
995 we are running a different TSO, so write a schedule event to log file
996 NB: If we use fair scheduling we also have to write a deschedule
997 event for LastTSO; with unfair scheduling we know that the
998 previous tso has blocked whenever we switch to another tso, so
999 we don't need it in GUM for now
1001 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
1002 GR_SCHEDULE, t, (StgClosure *)NULL, 0, 0);
1003 emitSchedule = rtsFalse;
1007 #else /* !GRAN && !PAR */
1009 /* grab a thread from the run queue */
1010 ASSERT(run_queue_hd != END_TSO_QUEUE);
1011 t = POP_RUN_QUEUE();
1012 // Sanity check the thread we're about to run. This can be
1013 // expensive if there is lots of thread switching going on...
1014 IF_DEBUG(sanity,checkTSO(t));
1017 cap->r.rCurrentTSO = t;
1019 /* context switches are now initiated by the timer signal, unless
1020 * the user specified "context switch as often as possible", with
1025 RtsFlags.ProfFlags.profileInterval == 0 ||
1027 (RtsFlags.ConcFlags.ctxtSwitchTicks == 0
1028 && (run_queue_hd != END_TSO_QUEUE
1029 || blocked_queue_hd != END_TSO_QUEUE
1030 || sleeping_queue != END_TSO_QUEUE)))
1035 RELEASE_LOCK(&sched_mutex);
1037 IF_DEBUG(scheduler, sched_belch("-->> Running TSO %ld (%p) %s ...",
1038 t->id, t, whatNext_strs[t->what_next]));
1041 startHeapProfTimer();
1044 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
1045 /* Run the current thread
1047 switch (cap->r.rCurrentTSO->what_next) {
1049 case ThreadComplete:
1050 /* Thread already finished, return to scheduler. */
1051 ret = ThreadFinished;
1053 case ThreadEnterGHC:
1054 ret = StgRun((StgFunPtr) stg_enterStackTop, &cap->r);
1057 ret = StgRun((StgFunPtr) stg_returnToStackTop, &cap->r);
1059 case ThreadEnterInterp:
1060 ret = interpretBCO(cap);
1063 barf("schedule: invalid what_next field");
1065 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
1067 /* Costs for the scheduler are assigned to CCS_SYSTEM */
1069 stopHeapProfTimer();
1073 ACQUIRE_LOCK(&sched_mutex);
1076 IF_DEBUG(scheduler,fprintf(stderr,"scheduler (task %ld): ", osThreadId()););
1077 #elif !defined(GRAN) && !defined(PAR)
1078 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: "););
1080 t = cap->r.rCurrentTSO;
1083 /* HACK 675: if the last thread didn't yield, make sure to print a
1084 SCHEDULE event to the log file when StgRunning the next thread, even
1085 if it is the same one as before */
1087 TimeOfLastYield = CURRENT_TIME;
1093 IF_DEBUG(gran, DumpGranEvent(GR_DESCHEDULE, t));
1094 globalGranStats.tot_heapover++;
1096 globalParStats.tot_heapover++;
1099 // did the task ask for a large block?
1100 if (cap->r.rHpAlloc > BLOCK_SIZE_W) {
1101 // if so, get one and push it on the front of the nursery.
1105 blocks = (nat)BLOCK_ROUND_UP(cap->r.rHpAlloc * sizeof(W_)) / BLOCK_SIZE;
1107 IF_DEBUG(scheduler,belch("--<< thread %ld (%p; %s) stopped: requesting a large block (size %d)",
1109 whatNext_strs[t->what_next], blocks));
1111 // don't do this if it would push us over the
1112 // alloc_blocks_lim limit; we'll GC first.
1113 if (alloc_blocks + blocks < alloc_blocks_lim) {
1115 alloc_blocks += blocks;
1116 bd = allocGroup( blocks );
1118 // link the new group into the list
1119 bd->link = cap->r.rCurrentNursery;
1120 bd->u.back = cap->r.rCurrentNursery->u.back;
1121 if (cap->r.rCurrentNursery->u.back != NULL) {
1122 cap->r.rCurrentNursery->u.back->link = bd;
1124 ASSERT(g0s0->blocks == cap->r.rCurrentNursery &&
1125 g0s0->blocks == cap->r.rNursery);
1126 cap->r.rNursery = g0s0->blocks = bd;
1128 cap->r.rCurrentNursery->u.back = bd;
1130 // initialise it as a nursery block. We initialise the
1131 // step, gen_no, and flags field of *every* sub-block in
1132 // this large block, because this is easier than making
1133 // sure that we always find the block head of a large
1134 // block whenever we call Bdescr() (eg. evacuate() and
1135 // isAlive() in the GC would both have to do this, at
1139 for (x = bd; x < bd + blocks; x++) {
1147 // don't forget to update the block count in g0s0.
1148 g0s0->n_blocks += blocks;
1149 ASSERT(countBlocks(g0s0->blocks) == g0s0->n_blocks);
1151 // now update the nursery to point to the new block
1152 cap->r.rCurrentNursery = bd;
1154 // we might be unlucky and have another thread get on the
1155 // run queue before us and steal the large block, but in that
1156 // case the thread will just end up requesting another large
1158 PUSH_ON_RUN_QUEUE(t);
1163 /* make all the running tasks block on a condition variable,
1164 * maybe set context_switch and wait till they all pile in,
1165 * then have them wait on a GC condition variable.
1167 IF_DEBUG(scheduler,belch("--<< thread %ld (%p; %s) stopped: HeapOverflow",
1168 t->id, t, whatNext_strs[t->what_next]));
1171 ASSERT(!is_on_queue(t,CurrentProc));
1173 /* Currently we emit a DESCHEDULE event before GC in GUM.
1174 ToDo: either add separate event to distinguish SYSTEM time from rest
1175 or just nuke this DESCHEDULE (and the following SCHEDULE) */
1176 if (0 && RtsFlags.ParFlags.ParStats.Full) {
1177 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
1178 GR_DESCHEDULE, t, (StgClosure *)NULL, 0, 0);
1179 emitSchedule = rtsTrue;
1183 ready_to_gc = rtsTrue;
1184 context_switch = 1; /* stop other threads ASAP */
1185 PUSH_ON_RUN_QUEUE(t);
1186 /* actual GC is done at the end of the while loop */
1192 DumpGranEvent(GR_DESCHEDULE, t));
1193 globalGranStats.tot_stackover++;
1196 // DumpGranEvent(GR_DESCHEDULE, t);
1197 globalParStats.tot_stackover++;
1199 IF_DEBUG(scheduler,belch("--<< thread %ld (%p; %s) stopped, StackOverflow",
1200 t->id, t, whatNext_strs[t->what_next]));
1201 /* just adjust the stack for this thread, then pop it back
1207 /* enlarge the stack */
1208 StgTSO *new_t = threadStackOverflow(t);
1210 /* This TSO has moved, so update any pointers to it from the
1211 * main thread stack. It better not be on any other queues...
1212 * (it shouldn't be).
1214 for (m = main_threads; m != NULL; m = m->link) {
1219 threadPaused(new_t);
1220 PUSH_ON_RUN_QUEUE(new_t);
1224 case ThreadYielding:
1227 DumpGranEvent(GR_DESCHEDULE, t));
1228 globalGranStats.tot_yields++;
1231 // DumpGranEvent(GR_DESCHEDULE, t);
1232 globalParStats.tot_yields++;
1234 /* put the thread back on the run queue. Then, if we're ready to
1235 * GC, check whether this is the last task to stop. If so, wake
1236 * up the GC thread. getThread will block during a GC until the
1240 if (t->what_next == ThreadEnterInterp) {
1241 /* ToDo: or maybe a timer expired when we were in Hugs?
1242 * or maybe someone hit ctrl-C
1244 belch("--<< thread %ld (%p; %s) stopped to switch to Hugs",
1245 t->id, t, whatNext_strs[t->what_next]);
1247 belch("--<< thread %ld (%p; %s) stopped, yielding",
1248 t->id, t, whatNext_strs[t->what_next]);
1255 //belch("&& Doing sanity check on yielding TSO %ld.", t->id);
1257 ASSERT(t->link == END_TSO_QUEUE);
1259 ASSERT(!is_on_queue(t,CurrentProc));
1262 //belch("&& Doing sanity check on all ThreadQueues (and their TSOs).");
1263 checkThreadQsSanity(rtsTrue));
1266 if (RtsFlags.ParFlags.doFairScheduling) {
1267 /* this does round-robin scheduling; good for concurrency */
1268 APPEND_TO_RUN_QUEUE(t);
1270 /* this does unfair scheduling; good for parallelism */
1271 PUSH_ON_RUN_QUEUE(t);
1274 /* this does round-robin scheduling; good for concurrency */
1275 APPEND_TO_RUN_QUEUE(t);
1278 /* add a ContinueThread event to actually process the thread */
1279 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
1281 t, (StgClosure*)NULL, (rtsSpark*)NULL);
1283 belch("GRAN: eventq and runnableq after adding yielded thread to queue again:");
1292 belch("--<< thread %ld (%p; %s) stopped, blocking on node %p [PE %d] with BQ: ",
1293 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)));
1294 if (t->block_info.closure!=(StgClosure*)NULL) print_bq(t->block_info.closure));
1296 // ??? needed; should emit block before
1298 DumpGranEvent(GR_DESCHEDULE, t));
1299 prune_eventq(t, (StgClosure *)NULL); // prune ContinueThreads for t
1302 ASSERT(procStatus[CurrentProc]==Busy ||
1303 ((procStatus[CurrentProc]==Fetching) &&
1304 (t->block_info.closure!=(StgClosure*)NULL)));
1305 if (run_queue_hds[CurrentProc] == END_TSO_QUEUE &&
1306 !(!RtsFlags.GranFlags.DoAsyncFetch &&
1307 procStatus[CurrentProc]==Fetching))
1308 procStatus[CurrentProc] = Idle;
1312 belch("--<< thread %ld (%p; %s) stopped, blocking on node %p with BQ: ",
1313 t->id, t, whatNext_strs[t->what_next], t->block_info.closure));
1316 if (t->block_info.closure!=(StgClosure*)NULL)
1317 print_bq(t->block_info.closure));
1319 /* Send a fetch (if BlockedOnGA) and dump event to log file */
1322 /* whatever we schedule next, we must log that schedule */
1323 emitSchedule = rtsTrue;
1326 /* don't need to do anything. Either the thread is blocked on
1327 * I/O, in which case we'll have called addToBlockedQueue
1328 * previously, or it's blocked on an MVar or Blackhole, in which
1329 * case it'll be on the relevant queue already.
1332 fprintf(stderr, "--<< thread %d (%p) stopped: ", t->id, t);
1333 printThreadBlockage(t);
1334 fprintf(stderr, "\n"));
1336 /* Only for dumping event to log file
1337 ToDo: do I need this in GranSim, too?
1344 case ThreadFinished:
1345 /* Need to check whether this was a main thread, and if so, signal
1346 * the task that started it with the return value. If we have no
1347 * more main threads, we probably need to stop all the tasks until
1350 /* We also end up here if the thread kills itself with an
1351 * uncaught exception, see Exception.hc.
1353 IF_DEBUG(scheduler,belch("--++ thread %d (%p) finished", t->id, t));
1355 endThread(t, CurrentProc); // clean-up the thread
1357 /* For now all are advisory -- HWL */
1358 //if(t->priority==AdvisoryPriority) ??
1359 advisory_thread_count--;
1362 if(t->dist.priority==RevalPriority)
1366 if (RtsFlags.ParFlags.ParStats.Full &&
1367 !RtsFlags.ParFlags.ParStats.Suppressed)
1368 DumpEndEvent(CURRENT_PROC, t, rtsFalse /* not mandatory */);
1373 barf("schedule: invalid thread return code %d", (int)ret);
1377 if (RtsFlags.ProfFlags.profileInterval==0 || performHeapProfile) {
1378 GarbageCollect(GetRoots, rtsTrue);
1380 performHeapProfile = rtsFalse;
1381 ready_to_gc = rtsFalse; // we already GC'd
1387 && allFreeCapabilities()
1390 /* everybody back, start the GC.
1391 * Could do it in this thread, or signal a condition var
1392 * to do it in another thread. Either way, we need to
1393 * broadcast on gc_pending_cond afterward.
1395 #if defined(RTS_SUPPORTS_THREADS)
1396 IF_DEBUG(scheduler,sched_belch("doing GC"));
1398 GarbageCollect(GetRoots,rtsFalse);
1399 ready_to_gc = rtsFalse;
1401 broadcastCondition(&gc_pending_cond);
1404 /* add a ContinueThread event to continue execution of current thread */
1405 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
1407 t, (StgClosure*)NULL, (rtsSpark*)NULL);
1409 fprintf(stderr, "GRAN: eventq and runnableq after Garbage collection:\n");
1417 IF_GRAN_DEBUG(unused,
1418 print_eventq(EventHd));
1420 event = get_next_event();
1423 /* ToDo: wait for next message to arrive rather than busy wait */
1426 } /* end of while(1) */
1428 IF_PAR_DEBUG(verbose,
1429 belch("== Leaving schedule() after having received Finish"));
1432 /* ---------------------------------------------------------------------------
1433 * Singleton fork(). Do not copy any running threads.
1434 * ------------------------------------------------------------------------- */
1436 StgInt forkProcess(StgTSO* tso) {
1438 #ifndef mingw32_TARGET_OS
1444 IF_DEBUG(scheduler,sched_belch("forking!"));
1447 if (pid) { /* parent */
1449 /* just return the pid */
1451 } else { /* child */
1452 /* wipe all other threads */
1453 run_queue_hd = run_queue_tl = tso;
1454 tso->link = END_TSO_QUEUE;
1456 /* When clearing out the threads, we need to ensure
1457 that a 'main thread' is left behind; if there isn't,
1458 the Scheduler will shutdown next time it is entered.
1460 ==> we don't kill a thread that's on the main_threads
1461 list (nor the current thread.)
1463 [ Attempts at implementing the more ambitious scheme of
1464 killing the main_threads also, and then adding the
1465 current thread onto the main_threads list if it wasn't
1466 there already, failed -- waitThread() (for one) wasn't
1467 up to it. If it proves to be desirable to also kill
1468 the main threads, then this scheme will have to be
1469 revisited (and fully debugged!)
1474 /* DO NOT TOUCH THE QUEUES directly because most of the code around
1475 us is picky about finding the thread still in its queue when
1476 handling the deleteThread() */
1478 for (t = all_threads; t != END_TSO_QUEUE; t = next) {
1481 /* Don't kill the current thread.. */
1482 if (t->id == tso->id) continue;
1484 /* ..or a main thread */
1485 for (m = main_threads; m != NULL; m = m->link) {
1486 if (m->tso->id == t->id) {
1498 barf("forkProcess#: primop not implemented for mingw32, sorry! (%u)\n", tso->id);
1499 /* pointlessly printing out the TSOs 'id' to avoid CC unused warning. */
1501 #endif /* mingw32 */
1504 /* ---------------------------------------------------------------------------
1505 * deleteAllThreads(): kill all the live threads.
1507 * This is used when we catch a user interrupt (^C), before performing
1508 * any necessary cleanups and running finalizers.
1510 * Locks: sched_mutex held.
1511 * ------------------------------------------------------------------------- */
1513 void deleteAllThreads ( void )
1516 IF_DEBUG(scheduler,sched_belch("deleting all threads"));
1517 for (t = all_threads; t != END_TSO_QUEUE; t = next) {
1518 next = t->global_link;
1521 run_queue_hd = run_queue_tl = END_TSO_QUEUE;
1522 blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
1523 sleeping_queue = END_TSO_QUEUE;
1526 /* startThread and insertThread are now in GranSim.c -- HWL */
1529 //@node Suspend and Resume, Run queue code, Main scheduling loop, Main scheduling code
1530 //@subsection Suspend and Resume
1532 /* ---------------------------------------------------------------------------
1533 * Suspending & resuming Haskell threads.
1535 * When making a "safe" call to C (aka _ccall_GC), the task gives back
1536 * its capability before calling the C function. This allows another
1537 * task to pick up the capability and carry on running Haskell
1538 * threads. It also means that if the C call blocks, it won't lock
1541 * The Haskell thread making the C call is put to sleep for the
1542 * duration of the call, on the susepended_ccalling_threads queue. We
1543 * give out a token to the task, which it can use to resume the thread
1544 * on return from the C function.
1545 * ------------------------------------------------------------------------- */
1548 suspendThread( StgRegTable *reg,
1550 #if !defined(RTS_SUPPORTS_THREADS) && !defined(DEBUG)
1558 /* assume that *reg is a pointer to the StgRegTable part
1561 cap = (Capability *)((void *)reg - sizeof(StgFunTable));
1563 ACQUIRE_LOCK(&sched_mutex);
1566 sched_belch("thread %d did a _ccall_gc (is_concurrent: %d)", cap->r.rCurrentTSO->id,concCall));
1568 threadPaused(cap->r.rCurrentTSO);
1569 cap->r.rCurrentTSO->link = suspended_ccalling_threads;
1570 suspended_ccalling_threads = cap->r.rCurrentTSO;
1572 #if defined(RTS_SUPPORTS_THREADS)
1573 cap->r.rCurrentTSO->why_blocked = BlockedOnCCall;
1576 /* Use the thread ID as the token; it should be unique */
1577 tok = cap->r.rCurrentTSO->id;
1579 /* Hand back capability */
1580 releaseCapability(cap);
1582 #if defined(RTS_SUPPORTS_THREADS)
1583 /* Preparing to leave the RTS, so ensure there's a native thread/task
1584 waiting to take over.
1586 ToDo: optimise this and only create a new task if there's a need
1587 for one (i.e., if there's only one Concurrent Haskell thread alive,
1588 there's no need to create a new task).
1590 IF_DEBUG(scheduler, sched_belch("worker thread (%d): leaving RTS", tok));
1592 startTask(taskStart);
1596 /* Other threads _might_ be available for execution; signal this */
1598 RELEASE_LOCK(&sched_mutex);
1603 resumeThread( StgInt tok,
1605 #if !defined(RTS_SUPPORTS_THREADS)
1610 StgTSO *tso, **prev;
1613 #if defined(RTS_SUPPORTS_THREADS)
1614 /* Wait for permission to re-enter the RTS with the result. */
1616 ACQUIRE_LOCK(&sched_mutex);
1617 grabReturnCapability(&sched_mutex, &cap);
1619 grabCapability(&cap);
1622 grabCapability(&cap);
1625 /* Remove the thread off of the suspended list */
1626 prev = &suspended_ccalling_threads;
1627 for (tso = suspended_ccalling_threads;
1628 tso != END_TSO_QUEUE;
1629 prev = &tso->link, tso = tso->link) {
1630 if (tso->id == (StgThreadID)tok) {
1635 if (tso == END_TSO_QUEUE) {
1636 barf("resumeThread: thread not found");
1638 tso->link = END_TSO_QUEUE;
1639 /* Reset blocking status */
1640 tso->why_blocked = NotBlocked;
1642 cap->r.rCurrentTSO = tso;
1643 RELEASE_LOCK(&sched_mutex);
1648 /* ---------------------------------------------------------------------------
1650 * ------------------------------------------------------------------------ */
1651 static void unblockThread(StgTSO *tso);
1653 /* ---------------------------------------------------------------------------
1654 * Comparing Thread ids.
1656 * This is used from STG land in the implementation of the
1657 * instances of Eq/Ord for ThreadIds.
1658 * ------------------------------------------------------------------------ */
1661 cmp_thread(StgPtr tso1, StgPtr tso2)
1663 StgThreadID id1 = ((StgTSO *)tso1)->id;
1664 StgThreadID id2 = ((StgTSO *)tso2)->id;
1666 if (id1 < id2) return (-1);
1667 if (id1 > id2) return 1;
1671 /* ---------------------------------------------------------------------------
1672 * Fetching the ThreadID from an StgTSO.
1674 * This is used in the implementation of Show for ThreadIds.
1675 * ------------------------------------------------------------------------ */
1677 rts_getThreadId(StgPtr tso)
1679 return ((StgTSO *)tso)->id;
1684 labelThread(StgPtr tso, char *label)
1689 /* Caveat: Once set, you can only set the thread name to "" */
1690 len = strlen(label)+1;
1693 fprintf(stderr,"insufficient memory for labelThread!\n");
1695 strncpy(buf,label,len);
1696 /* Update will free the old memory for us */
1697 updateThreadLabel((StgWord)tso,buf);
1701 /* ---------------------------------------------------------------------------
1702 Create a new thread.
1704 The new thread starts with the given stack size. Before the
1705 scheduler can run, however, this thread needs to have a closure
1706 (and possibly some arguments) pushed on its stack. See
1707 pushClosure() in Schedule.h.
1709 createGenThread() and createIOThread() (in SchedAPI.h) are
1710 convenient packaged versions of this function.
1712 currently pri (priority) is only used in a GRAN setup -- HWL
1713 ------------------------------------------------------------------------ */
1714 //@cindex createThread
1716 /* currently pri (priority) is only used in a GRAN setup -- HWL */
1718 createThread(nat size, StgInt pri)
1721 createThread(nat size)
1728 /* First check whether we should create a thread at all */
1730 /* check that no more than RtsFlags.ParFlags.maxThreads threads are created */
1731 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads) {
1733 belch("{createThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
1734 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
1735 return END_TSO_QUEUE;
1741 ASSERT(!RtsFlags.GranFlags.Light || CurrentProc==0);
1744 // ToDo: check whether size = stack_size - TSO_STRUCT_SIZEW
1746 /* catch ridiculously small stack sizes */
1747 if (size < MIN_STACK_WORDS + TSO_STRUCT_SIZEW) {
1748 size = MIN_STACK_WORDS + TSO_STRUCT_SIZEW;
1751 stack_size = size - TSO_STRUCT_SIZEW;
1753 tso = (StgTSO *)allocate(size);
1754 TICK_ALLOC_TSO(stack_size, 0);
1756 SET_HDR(tso, &stg_TSO_info, CCS_SYSTEM);
1758 SET_GRAN_HDR(tso, ThisPE);
1760 tso->what_next = ThreadEnterGHC;
1762 /* tso->id needs to be unique. For now we use a heavyweight mutex to
1763 * protect the increment operation on next_thread_id.
1764 * In future, we could use an atomic increment instead.
1766 ACQUIRE_LOCK(&thread_id_mutex);
1767 tso->id = next_thread_id++;
1768 RELEASE_LOCK(&thread_id_mutex);
1770 tso->why_blocked = NotBlocked;
1771 tso->blocked_exceptions = NULL;
1773 tso->stack_size = stack_size;
1774 tso->max_stack_size = round_to_mblocks(RtsFlags.GcFlags.maxStkSize)
1776 tso->sp = (P_)&(tso->stack) + stack_size;
1779 tso->prof.CCCS = CCS_MAIN;
1782 /* put a stop frame on the stack */
1783 tso->sp -= sizeofW(StgStopFrame);
1784 SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_SYSTEM);
1785 tso->su = (StgUpdateFrame*)tso->sp;
1789 tso->link = END_TSO_QUEUE;
1790 /* uses more flexible routine in GranSim */
1791 insertThread(tso, CurrentProc);
1793 /* In a non-GranSim setup the pushing of a TSO onto the runq is separated
1799 if (RtsFlags.GranFlags.GranSimStats.Full)
1800 DumpGranEvent(GR_START,tso);
1802 if (RtsFlags.ParFlags.ParStats.Full)
1803 DumpGranEvent(GR_STARTQ,tso);
1804 /* HACk to avoid SCHEDULE
1808 /* Link the new thread on the global thread list.
1810 tso->global_link = all_threads;
1814 tso->dist.priority = MandatoryPriority; //by default that is...
1818 tso->gran.pri = pri;
1820 tso->gran.magic = TSO_MAGIC; // debugging only
1822 tso->gran.sparkname = 0;
1823 tso->gran.startedat = CURRENT_TIME;
1824 tso->gran.exported = 0;
1825 tso->gran.basicblocks = 0;
1826 tso->gran.allocs = 0;
1827 tso->gran.exectime = 0;
1828 tso->gran.fetchtime = 0;
1829 tso->gran.fetchcount = 0;
1830 tso->gran.blocktime = 0;
1831 tso->gran.blockcount = 0;
1832 tso->gran.blockedat = 0;
1833 tso->gran.globalsparks = 0;
1834 tso->gran.localsparks = 0;
1835 if (RtsFlags.GranFlags.Light)
1836 tso->gran.clock = Now; /* local clock */
1838 tso->gran.clock = 0;
1840 IF_DEBUG(gran,printTSO(tso));
1843 tso->par.magic = TSO_MAGIC; // debugging only
1845 tso->par.sparkname = 0;
1846 tso->par.startedat = CURRENT_TIME;
1847 tso->par.exported = 0;
1848 tso->par.basicblocks = 0;
1849 tso->par.allocs = 0;
1850 tso->par.exectime = 0;
1851 tso->par.fetchtime = 0;
1852 tso->par.fetchcount = 0;
1853 tso->par.blocktime = 0;
1854 tso->par.blockcount = 0;
1855 tso->par.blockedat = 0;
1856 tso->par.globalsparks = 0;
1857 tso->par.localsparks = 0;
1861 globalGranStats.tot_threads_created++;
1862 globalGranStats.threads_created_on_PE[CurrentProc]++;
1863 globalGranStats.tot_sq_len += spark_queue_len(CurrentProc);
1864 globalGranStats.tot_sq_probes++;
1866 // collect parallel global statistics (currently done together with GC stats)
1867 if (RtsFlags.ParFlags.ParStats.Global &&
1868 RtsFlags.GcFlags.giveStats > NO_GC_STATS) {
1869 //fprintf(stderr, "Creating thread %d @ %11.2f\n", tso->id, usertime());
1870 globalParStats.tot_threads_created++;
1876 belch("==__ schedule: Created TSO %d (%p);",
1877 CurrentProc, tso, tso->id));
1879 IF_PAR_DEBUG(verbose,
1880 belch("==__ schedule: Created TSO %d (%p); %d threads active",
1881 tso->id, tso, advisory_thread_count));
1883 IF_DEBUG(scheduler,sched_belch("created thread %ld, stack size = %lx words",
1884 tso->id, tso->stack_size));
1891 all parallel thread creation calls should fall through the following routine.
1894 createSparkThread(rtsSpark spark)
1896 ASSERT(spark != (rtsSpark)NULL);
1897 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads)
1899 barf("{createSparkThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
1900 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
1901 return END_TSO_QUEUE;
1905 tso = createThread(RtsFlags.GcFlags.initialStkSize);
1906 if (tso==END_TSO_QUEUE)
1907 barf("createSparkThread: Cannot create TSO");
1909 tso->priority = AdvisoryPriority;
1911 pushClosure(tso,spark);
1912 PUSH_ON_RUN_QUEUE(tso);
1913 advisory_thread_count++;
1920 Turn a spark into a thread.
1921 ToDo: fix for SMP (needs to acquire SCHED_MUTEX!)
1924 //@cindex activateSpark
1926 activateSpark (rtsSpark spark)
1930 tso = createSparkThread(spark);
1931 if (RtsFlags.ParFlags.ParStats.Full) {
1932 //ASSERT(run_queue_hd == END_TSO_QUEUE); // I think ...
1933 IF_PAR_DEBUG(verbose,
1934 belch("==^^ activateSpark: turning spark of closure %p (%s) into a thread",
1935 (StgClosure *)spark, info_type((StgClosure *)spark)));
1937 // ToDo: fwd info on local/global spark to thread -- HWL
1938 // tso->gran.exported = spark->exported;
1939 // tso->gran.locked = !spark->global;
1940 // tso->gran.sparkname = spark->name;
1946 static SchedulerStatus waitThread_(/*out*/StgMainThread* m
1947 #if defined(THREADED_RTS)
1948 , rtsBool blockWaiting
1953 /* ---------------------------------------------------------------------------
1956 * scheduleThread puts a thread on the head of the runnable queue.
1957 * This will usually be done immediately after a thread is created.
1958 * The caller of scheduleThread must create the thread using e.g.
1959 * createThread and push an appropriate closure
1960 * on this thread's stack before the scheduler is invoked.
1961 * ------------------------------------------------------------------------ */
1963 static void scheduleThread_ (StgTSO* tso, rtsBool createTask);
1966 scheduleThread_(StgTSO *tso
1967 , rtsBool createTask
1968 #if !defined(THREADED_RTS)
1973 // Precondition: sched_mutex must be held.
1975 /* Put the new thread on the head of the runnable queue. The caller
1976 * better push an appropriate closure on this thread's stack
1977 * beforehand. In the SMP case, the thread may start running as
1978 * soon as we release the scheduler lock below.
1980 PUSH_ON_RUN_QUEUE(tso);
1981 #if defined(THREADED_RTS)
1982 /* If main() is scheduling a thread, don't bother creating a
1986 startTask(taskStart);
1992 IF_DEBUG(scheduler,printTSO(tso));
1996 void scheduleThread(StgTSO* tso)
1998 ACQUIRE_LOCK(&sched_mutex);
1999 scheduleThread_(tso, rtsFalse);
2000 RELEASE_LOCK(&sched_mutex);
2004 scheduleWaitThread(StgTSO* tso, /*[out]*/HaskellObj* ret)
2008 m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
2012 #if defined(RTS_SUPPORTS_THREADS)
2013 initCondition(&m->wakeup);
2016 /* Put the thread on the main-threads list prior to scheduling the TSO.
2017 Failure to do so introduces a race condition in the MT case (as
2018 identified by Wolfgang Thaller), whereby the new task/OS thread
2019 created by scheduleThread_() would complete prior to the thread
2020 that spawned it managed to put 'itself' on the main-threads list.
2021 The upshot of it all being that the worker thread wouldn't get to
2022 signal the completion of the its work item for the main thread to
2023 see (==> it got stuck waiting.) -- sof 6/02.
2025 ACQUIRE_LOCK(&sched_mutex);
2026 IF_DEBUG(scheduler, sched_belch("== scheduler: waiting for thread (%d)\n", tso->id));
2028 m->link = main_threads;
2031 scheduleThread_(tso, rtsTrue);
2032 #if defined(THREADED_RTS)
2033 return waitThread_(m, rtsTrue); // waitThread_ releases sched_mutex
2035 return waitThread_(m);
2039 /* ---------------------------------------------------------------------------
2042 * Initialise the scheduler. This resets all the queues - if the
2043 * queues contained any threads, they'll be garbage collected at the
2046 * ------------------------------------------------------------------------ */
2050 term_handler(int sig STG_UNUSED)
2053 ACQUIRE_LOCK(&term_mutex);
2055 RELEASE_LOCK(&term_mutex);
2066 for (i=0; i<=MAX_PROC; i++) {
2067 run_queue_hds[i] = END_TSO_QUEUE;
2068 run_queue_tls[i] = END_TSO_QUEUE;
2069 blocked_queue_hds[i] = END_TSO_QUEUE;
2070 blocked_queue_tls[i] = END_TSO_QUEUE;
2071 ccalling_threadss[i] = END_TSO_QUEUE;
2072 sleeping_queue = END_TSO_QUEUE;
2075 run_queue_hd = END_TSO_QUEUE;
2076 run_queue_tl = END_TSO_QUEUE;
2077 blocked_queue_hd = END_TSO_QUEUE;
2078 blocked_queue_tl = END_TSO_QUEUE;
2079 sleeping_queue = END_TSO_QUEUE;
2082 suspended_ccalling_threads = END_TSO_QUEUE;
2084 main_threads = NULL;
2085 all_threads = END_TSO_QUEUE;
2090 RtsFlags.ConcFlags.ctxtSwitchTicks =
2091 RtsFlags.ConcFlags.ctxtSwitchTime / TICK_MILLISECS;
2093 #if defined(RTS_SUPPORTS_THREADS)
2094 /* Initialise the mutex and condition variables used by
2096 initMutex(&sched_mutex);
2097 initMutex(&term_mutex);
2098 initMutex(&thread_id_mutex);
2100 initCondition(&thread_ready_cond);
2104 initCondition(&gc_pending_cond);
2107 #if defined(RTS_SUPPORTS_THREADS)
2108 ACQUIRE_LOCK(&sched_mutex);
2111 /* Install the SIGHUP handler */
2114 struct sigaction action,oact;
2116 action.sa_handler = term_handler;
2117 sigemptyset(&action.sa_mask);
2118 action.sa_flags = 0;
2119 if (sigaction(SIGTERM, &action, &oact) != 0) {
2120 barf("can't install TERM handler");
2125 /* A capability holds the state a native thread needs in
2126 * order to execute STG code. At least one capability is
2127 * floating around (only SMP builds have more than one).
2131 #if defined(RTS_SUPPORTS_THREADS)
2132 /* start our haskell execution tasks */
2134 startTaskManager(RtsFlags.ParFlags.nNodes, taskStart);
2136 startTaskManager(0,taskStart);
2140 #if /* defined(SMP) ||*/ defined(PAR)
2144 #if defined(RTS_SUPPORTS_THREADS)
2145 RELEASE_LOCK(&sched_mutex);
2151 exitScheduler( void )
2153 #if defined(RTS_SUPPORTS_THREADS)
2156 shutting_down_scheduler = rtsTrue;
2159 /* -----------------------------------------------------------------------------
2160 Managing the per-task allocation areas.
2162 Each capability comes with an allocation area. These are
2163 fixed-length block lists into which allocation can be done.
2165 ToDo: no support for two-space collection at the moment???
2166 -------------------------------------------------------------------------- */
2168 /* -----------------------------------------------------------------------------
2169 * waitThread is the external interface for running a new computation
2170 * and waiting for the result.
2172 * In the non-SMP case, we create a new main thread, push it on the
2173 * main-thread stack, and invoke the scheduler to run it. The
2174 * scheduler will return when the top main thread on the stack has
2175 * completed or died, and fill in the necessary fields of the
2176 * main_thread structure.
2178 * In the SMP case, we create a main thread as before, but we then
2179 * create a new condition variable and sleep on it. When our new
2180 * main thread has completed, we'll be woken up and the status/result
2181 * will be in the main_thread struct.
2182 * -------------------------------------------------------------------------- */
2185 howManyThreadsAvail ( void )
2189 for (q = run_queue_hd; q != END_TSO_QUEUE; q = q->link)
2191 for (q = blocked_queue_hd; q != END_TSO_QUEUE; q = q->link)
2193 for (q = sleeping_queue; q != END_TSO_QUEUE; q = q->link)
2199 finishAllThreads ( void )
2202 while (run_queue_hd != END_TSO_QUEUE) {
2203 waitThread ( run_queue_hd, NULL);
2205 while (blocked_queue_hd != END_TSO_QUEUE) {
2206 waitThread ( blocked_queue_hd, NULL);
2208 while (sleeping_queue != END_TSO_QUEUE) {
2209 waitThread ( blocked_queue_hd, NULL);
2212 (blocked_queue_hd != END_TSO_QUEUE ||
2213 run_queue_hd != END_TSO_QUEUE ||
2214 sleeping_queue != END_TSO_QUEUE);
2218 waitThread(StgTSO *tso, /*out*/StgClosure **ret)
2222 m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
2226 #if defined(RTS_SUPPORTS_THREADS)
2227 initCondition(&m->wakeup);
2230 /* see scheduleWaitThread() comment */
2231 ACQUIRE_LOCK(&sched_mutex);
2232 IF_DEBUG(scheduler, sched_belch("== scheduler: waiting for thread (%d)\n", tso->id));
2233 m->link = main_threads;
2236 IF_DEBUG(scheduler, sched_belch("== scheduler: waiting for thread (%d)\n", tso->id));
2237 #if defined(THREADED_RTS)
2238 return waitThread_(m, rtsFalse); // waitThread_ releases sched_mutex
2240 return waitThread_(m);
2246 waitThread_(StgMainThread* m
2247 #if defined(THREADED_RTS)
2248 , rtsBool blockWaiting
2252 SchedulerStatus stat;
2254 // Precondition: sched_mutex must be held.
2255 IF_DEBUG(scheduler, sched_belch("== scheduler: new main thread (%d)\n", m->tso->id));
2257 #if defined(RTS_SUPPORTS_THREADS)
2259 # if defined(THREADED_RTS)
2260 if (!blockWaiting) {
2261 /* In the threaded case, the OS thread that called main()
2262 * gets to enter the RTS directly without going via another
2265 RELEASE_LOCK(&sched_mutex);
2267 ASSERT(m->stat != NoStatus);
2272 waitCondition(&m->wakeup, &sched_mutex);
2273 } while (m->stat == NoStatus);
2276 /* GranSim specific init */
2277 CurrentTSO = m->tso; // the TSO to run
2278 procStatus[MainProc] = Busy; // status of main PE
2279 CurrentProc = MainProc; // PE to run it on
2281 RELEASE_LOCK(&sched_mutex);
2284 RELEASE_LOCK(&sched_mutex);
2286 ASSERT(m->stat != NoStatus);
2291 #if defined(RTS_SUPPORTS_THREADS)
2292 closeCondition(&m->wakeup);
2295 IF_DEBUG(scheduler, fprintf(stderr, "== scheduler: main thread (%d) finished\n",
2299 #if defined(THREADED_RTS)
2302 RELEASE_LOCK(&sched_mutex);
2304 // Postcondition: sched_mutex must not be held
2308 //@node Run queue code, Garbage Collextion Routines, Suspend and Resume, Main scheduling code
2309 //@subsection Run queue code
2313 NB: In GranSim we have many run queues; run_queue_hd is actually a macro
2314 unfolding to run_queue_hds[CurrentProc], thus CurrentProc is an
2315 implicit global variable that has to be correct when calling these
2319 /* Put the new thread on the head of the runnable queue.
2320 * The caller of createThread better push an appropriate closure
2321 * on this thread's stack before the scheduler is invoked.
2323 static /* inline */ void
2324 add_to_run_queue(tso)
2327 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
2328 tso->link = run_queue_hd;
2330 if (run_queue_tl == END_TSO_QUEUE) {
2335 /* Put the new thread at the end of the runnable queue. */
2336 static /* inline */ void
2337 push_on_run_queue(tso)
2340 ASSERT(get_itbl((StgClosure *)tso)->type == TSO);
2341 ASSERT(run_queue_hd!=NULL && run_queue_tl!=NULL);
2342 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
2343 if (run_queue_hd == END_TSO_QUEUE) {
2346 run_queue_tl->link = tso;
2352 Should be inlined because it's used very often in schedule. The tso
2353 argument is actually only needed in GranSim, where we want to have the
2354 possibility to schedule *any* TSO on the run queue, irrespective of the
2355 actual ordering. Therefore, if tso is not the nil TSO then we traverse
2356 the run queue and dequeue the tso, adjusting the links in the queue.
2358 //@cindex take_off_run_queue
2359 static /* inline */ StgTSO*
2360 take_off_run_queue(StgTSO *tso) {
2364 qetlaHbogh Qu' ngaSbogh ghomDaQ {tso} yIteq!
2366 if tso is specified, unlink that tso from the run_queue (doesn't have
2367 to be at the beginning of the queue); GranSim only
2369 if (tso!=END_TSO_QUEUE) {
2370 /* find tso in queue */
2371 for (t=run_queue_hd, prev=END_TSO_QUEUE;
2372 t!=END_TSO_QUEUE && t!=tso;
2376 /* now actually dequeue the tso */
2377 if (prev!=END_TSO_QUEUE) {
2378 ASSERT(run_queue_hd!=t);
2379 prev->link = t->link;
2381 /* t is at beginning of thread queue */
2382 ASSERT(run_queue_hd==t);
2383 run_queue_hd = t->link;
2385 /* t is at end of thread queue */
2386 if (t->link==END_TSO_QUEUE) {
2387 ASSERT(t==run_queue_tl);
2388 run_queue_tl = prev;
2390 ASSERT(run_queue_tl!=t);
2392 t->link = END_TSO_QUEUE;
2394 /* take tso from the beginning of the queue; std concurrent code */
2396 if (t != END_TSO_QUEUE) {
2397 run_queue_hd = t->link;
2398 t->link = END_TSO_QUEUE;
2399 if (run_queue_hd == END_TSO_QUEUE) {
2400 run_queue_tl = END_TSO_QUEUE;
2409 //@node Garbage Collextion Routines, Blocking Queue Routines, Run queue code, Main scheduling code
2410 //@subsection Garbage Collextion Routines
2412 /* ---------------------------------------------------------------------------
2413 Where are the roots that we know about?
2415 - all the threads on the runnable queue
2416 - all the threads on the blocked queue
2417 - all the threads on the sleeping queue
2418 - all the thread currently executing a _ccall_GC
2419 - all the "main threads"
2421 ------------------------------------------------------------------------ */
2423 /* This has to be protected either by the scheduler monitor, or by the
2424 garbage collection monitor (probably the latter).
2429 GetRoots(evac_fn evac)
2434 for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
2435 if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
2436 evac((StgClosure **)&run_queue_hds[i]);
2437 if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
2438 evac((StgClosure **)&run_queue_tls[i]);
2440 if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
2441 evac((StgClosure **)&blocked_queue_hds[i]);
2442 if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
2443 evac((StgClosure **)&blocked_queue_tls[i]);
2444 if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
2445 evac((StgClosure **)&ccalling_threads[i]);
2452 if (run_queue_hd != END_TSO_QUEUE) {
2453 ASSERT(run_queue_tl != END_TSO_QUEUE);
2454 evac((StgClosure **)&run_queue_hd);
2455 evac((StgClosure **)&run_queue_tl);
2458 if (blocked_queue_hd != END_TSO_QUEUE) {
2459 ASSERT(blocked_queue_tl != END_TSO_QUEUE);
2460 evac((StgClosure **)&blocked_queue_hd);
2461 evac((StgClosure **)&blocked_queue_tl);
2464 if (sleeping_queue != END_TSO_QUEUE) {
2465 evac((StgClosure **)&sleeping_queue);
2469 if (suspended_ccalling_threads != END_TSO_QUEUE) {
2470 evac((StgClosure **)&suspended_ccalling_threads);
2473 #if defined(PAR) || defined(GRAN)
2474 markSparkQueue(evac);
2477 #ifndef mingw32_TARGET_OS
2478 // mark the signal handlers (signals should be already blocked)
2479 markSignalHandlers(evac);
2482 // main threads which have completed need to be retained until they
2483 // are dealt with in the main scheduler loop. They won't be
2484 // retained any other way: the GC will drop them from the
2485 // all_threads list, so we have to be careful to treat them as roots
2489 for (m = main_threads; m != NULL; m = m->link) {
2490 switch (m->tso->what_next) {
2491 case ThreadComplete:
2493 evac((StgClosure **)&m->tso);
2502 /* -----------------------------------------------------------------------------
2505 This is the interface to the garbage collector from Haskell land.
2506 We provide this so that external C code can allocate and garbage
2507 collect when called from Haskell via _ccall_GC.
2509 It might be useful to provide an interface whereby the programmer
2510 can specify more roots (ToDo).
2512 This needs to be protected by the GC condition variable above. KH.
2513 -------------------------------------------------------------------------- */
2515 static void (*extra_roots)(evac_fn);
2520 /* Obligated to hold this lock upon entry */
2521 ACQUIRE_LOCK(&sched_mutex);
2522 GarbageCollect(GetRoots,rtsFalse);
2523 RELEASE_LOCK(&sched_mutex);
2527 performMajorGC(void)
2529 ACQUIRE_LOCK(&sched_mutex);
2530 GarbageCollect(GetRoots,rtsTrue);
2531 RELEASE_LOCK(&sched_mutex);
2535 AllRoots(evac_fn evac)
2537 GetRoots(evac); // the scheduler's roots
2538 extra_roots(evac); // the user's roots
2542 performGCWithRoots(void (*get_roots)(evac_fn))
2544 ACQUIRE_LOCK(&sched_mutex);
2545 extra_roots = get_roots;
2546 GarbageCollect(AllRoots,rtsFalse);
2547 RELEASE_LOCK(&sched_mutex);
2550 /* -----------------------------------------------------------------------------
2553 If the thread has reached its maximum stack size, then raise the
2554 StackOverflow exception in the offending thread. Otherwise
2555 relocate the TSO into a larger chunk of memory and adjust its stack
2557 -------------------------------------------------------------------------- */
2560 threadStackOverflow(StgTSO *tso)
2562 nat new_stack_size, new_tso_size, diff, stack_words;
2566 IF_DEBUG(sanity,checkTSO(tso));
2567 if (tso->stack_size >= tso->max_stack_size) {
2570 belch("@@ threadStackOverflow of TSO %d (%p): stack too large (now %ld; max is %ld",
2571 tso->id, tso, tso->stack_size, tso->max_stack_size);
2572 /* If we're debugging, just print out the top of the stack */
2573 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2576 /* Send this thread the StackOverflow exception */
2577 raiseAsync(tso, (StgClosure *)stackOverflow_closure);
2581 /* Try to double the current stack size. If that takes us over the
2582 * maximum stack size for this thread, then use the maximum instead.
2583 * Finally round up so the TSO ends up as a whole number of blocks.
2585 new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
2586 new_tso_size = (nat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
2587 TSO_STRUCT_SIZE)/sizeof(W_);
2588 new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
2589 new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
2591 IF_DEBUG(scheduler, fprintf(stderr,"== scheduler: increasing stack size from %d words to %d.\n", tso->stack_size, new_stack_size));
2593 dest = (StgTSO *)allocate(new_tso_size);
2594 TICK_ALLOC_TSO(new_stack_size,0);
2596 /* copy the TSO block and the old stack into the new area */
2597 memcpy(dest,tso,TSO_STRUCT_SIZE);
2598 stack_words = tso->stack + tso->stack_size - tso->sp;
2599 new_sp = (P_)dest + new_tso_size - stack_words;
2600 memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
2602 /* relocate the stack pointers... */
2603 diff = (P_)new_sp - (P_)tso->sp; /* In *words* */
2604 dest->su = (StgUpdateFrame *) ((P_)dest->su + diff);
2606 dest->stack_size = new_stack_size;
2608 /* and relocate the update frame list */
2609 relocate_stack(dest, diff);
2611 /* Mark the old TSO as relocated. We have to check for relocated
2612 * TSOs in the garbage collector and any primops that deal with TSOs.
2614 * It's important to set the sp and su values to just beyond the end
2615 * of the stack, so we don't attempt to scavenge any part of the
2618 tso->what_next = ThreadRelocated;
2620 tso->sp = (P_)&(tso->stack[tso->stack_size]);
2621 tso->su = (StgUpdateFrame *)tso->sp;
2622 tso->why_blocked = NotBlocked;
2623 dest->mut_link = NULL;
2625 IF_PAR_DEBUG(verbose,
2626 belch("@@ threadStackOverflow of TSO %d (now at %p): stack size increased to %ld",
2627 tso->id, tso, tso->stack_size);
2628 /* If we're debugging, just print out the top of the stack */
2629 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2632 IF_DEBUG(sanity,checkTSO(tso));
2634 IF_DEBUG(scheduler,printTSO(dest));
2640 //@node Blocking Queue Routines, Exception Handling Routines, Garbage Collextion Routines, Main scheduling code
2641 //@subsection Blocking Queue Routines
2643 /* ---------------------------------------------------------------------------
2644 Wake up a queue that was blocked on some resource.
2645 ------------------------------------------------------------------------ */
2649 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2654 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2656 /* write RESUME events to log file and
2657 update blocked and fetch time (depending on type of the orig closure) */
2658 if (RtsFlags.ParFlags.ParStats.Full) {
2659 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
2660 GR_RESUMEQ, ((StgTSO *)bqe), ((StgTSO *)bqe)->block_info.closure,
2661 0, 0 /* spark_queue_len(ADVISORY_POOL) */);
2662 if (EMPTY_RUN_QUEUE())
2663 emitSchedule = rtsTrue;
2665 switch (get_itbl(node)->type) {
2667 ((StgTSO *)bqe)->par.fetchtime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2672 ((StgTSO *)bqe)->par.blocktime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2679 barf("{unblockOneLocked}Daq Qagh: unexpected closure in blocking queue");
2686 static StgBlockingQueueElement *
2687 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2690 PEs node_loc, tso_loc;
2692 node_loc = where_is(node); // should be lifted out of loop
2693 tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2694 tso_loc = where_is((StgClosure *)tso);
2695 if (IS_LOCAL_TO(PROCS(node),tso_loc)) { // TSO is local
2696 /* !fake_fetch => TSO is on CurrentProc is same as IS_LOCAL_TO */
2697 ASSERT(CurrentProc!=node_loc || tso_loc==CurrentProc);
2698 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.lunblocktime;
2699 // insertThread(tso, node_loc);
2700 new_event(tso_loc, tso_loc, CurrentTime[CurrentProc],
2702 tso, node, (rtsSpark*)NULL);
2703 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2706 } else { // TSO is remote (actually should be FMBQ)
2707 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.mpacktime +
2708 RtsFlags.GranFlags.Costs.gunblocktime +
2709 RtsFlags.GranFlags.Costs.latency;
2710 new_event(tso_loc, CurrentProc, CurrentTime[CurrentProc],
2712 tso, node, (rtsSpark*)NULL);
2713 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2716 /* the thread-queue-overhead is accounted for in either Resume or UnblockThread */
2718 fprintf(stderr," %s TSO %d (%p) [PE %d] (block_info.closure=%p) (next=%p) ,",
2719 (node_loc==tso_loc ? "Local" : "Global"),
2720 tso->id, tso, CurrentProc, tso->block_info.closure, tso->link));
2721 tso->block_info.closure = NULL;
2722 IF_DEBUG(scheduler,belch("-- Waking up thread %ld (%p)",
2726 static StgBlockingQueueElement *
2727 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2729 StgBlockingQueueElement *next;
2731 switch (get_itbl(bqe)->type) {
2733 ASSERT(((StgTSO *)bqe)->why_blocked != NotBlocked);
2734 /* if it's a TSO just push it onto the run_queue */
2736 // ((StgTSO *)bqe)->link = END_TSO_QUEUE; // debugging?
2737 PUSH_ON_RUN_QUEUE((StgTSO *)bqe);
2739 unblockCount(bqe, node);
2740 /* reset blocking status after dumping event */
2741 ((StgTSO *)bqe)->why_blocked = NotBlocked;
2745 /* if it's a BLOCKED_FETCH put it on the PendingFetches list */
2747 bqe->link = (StgBlockingQueueElement *)PendingFetches;
2748 PendingFetches = (StgBlockedFetch *)bqe;
2752 /* can ignore this case in a non-debugging setup;
2753 see comments on RBHSave closures above */
2755 /* check that the closure is an RBHSave closure */
2756 ASSERT(get_itbl((StgClosure *)bqe) == &stg_RBH_Save_0_info ||
2757 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_1_info ||
2758 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_2_info);
2762 barf("{unblockOneLocked}Daq Qagh: Unexpected IP (%#lx; %s) in blocking queue at %#lx\n",
2763 get_itbl((StgClosure *)bqe), info_type((StgClosure *)bqe),
2767 IF_PAR_DEBUG(bq, fprintf(stderr, ", %p (%s)", bqe, info_type((StgClosure*)bqe)));
2771 #else /* !GRAN && !PAR */
2773 unblockOneLocked(StgTSO *tso)
2777 ASSERT(get_itbl(tso)->type == TSO);
2778 ASSERT(tso->why_blocked != NotBlocked);
2779 tso->why_blocked = NotBlocked;
2781 PUSH_ON_RUN_QUEUE(tso);
2783 IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
2788 #if defined(GRAN) || defined(PAR)
2789 inline StgBlockingQueueElement *
2790 unblockOne(StgBlockingQueueElement *bqe, StgClosure *node)
2792 ACQUIRE_LOCK(&sched_mutex);
2793 bqe = unblockOneLocked(bqe, node);
2794 RELEASE_LOCK(&sched_mutex);
2799 unblockOne(StgTSO *tso)
2801 ACQUIRE_LOCK(&sched_mutex);
2802 tso = unblockOneLocked(tso);
2803 RELEASE_LOCK(&sched_mutex);
2810 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2812 StgBlockingQueueElement *bqe;
2817 belch("##-_ AwBQ for node %p on PE %d @ %ld by TSO %d (%p): ", \
2818 node, CurrentProc, CurrentTime[CurrentProc],
2819 CurrentTSO->id, CurrentTSO));
2821 node_loc = where_is(node);
2823 ASSERT(q == END_BQ_QUEUE ||
2824 get_itbl(q)->type == TSO || // q is either a TSO or an RBHSave
2825 get_itbl(q)->type == CONSTR); // closure (type constructor)
2826 ASSERT(is_unique(node));
2828 /* FAKE FETCH: magically copy the node to the tso's proc;
2829 no Fetch necessary because in reality the node should not have been
2830 moved to the other PE in the first place
2832 if (CurrentProc!=node_loc) {
2834 belch("## node %p is on PE %d but CurrentProc is %d (TSO %d); assuming fake fetch and adjusting bitmask (old: %#x)",
2835 node, node_loc, CurrentProc, CurrentTSO->id,
2836 // CurrentTSO, where_is(CurrentTSO),
2837 node->header.gran.procs));
2838 node->header.gran.procs = (node->header.gran.procs) | PE_NUMBER(CurrentProc);
2840 belch("## new bitmask of node %p is %#x",
2841 node, node->header.gran.procs));
2842 if (RtsFlags.GranFlags.GranSimStats.Global) {
2843 globalGranStats.tot_fake_fetches++;
2848 // ToDo: check: ASSERT(CurrentProc==node_loc);
2849 while (get_itbl(bqe)->type==TSO) { // q != END_TSO_QUEUE) {
2852 bqe points to the current element in the queue
2853 next points to the next element in the queue
2855 //tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2856 //tso_loc = where_is(tso);
2858 bqe = unblockOneLocked(bqe, node);
2861 /* if this is the BQ of an RBH, we have to put back the info ripped out of
2862 the closure to make room for the anchor of the BQ */
2863 if (bqe!=END_BQ_QUEUE) {
2864 ASSERT(get_itbl(node)->type == RBH && get_itbl(bqe)->type == CONSTR);
2866 ASSERT((info_ptr==&RBH_Save_0_info) ||
2867 (info_ptr==&RBH_Save_1_info) ||
2868 (info_ptr==&RBH_Save_2_info));
2870 /* cf. convertToRBH in RBH.c for writing the RBHSave closure */
2871 ((StgRBH *)node)->blocking_queue = (StgBlockingQueueElement *)((StgRBHSave *)bqe)->payload[0];
2872 ((StgRBH *)node)->mut_link = (StgMutClosure *)((StgRBHSave *)bqe)->payload[1];
2875 belch("## Filled in RBH_Save for %p (%s) at end of AwBQ",
2876 node, info_type(node)));
2879 /* statistics gathering */
2880 if (RtsFlags.GranFlags.GranSimStats.Global) {
2881 // globalGranStats.tot_bq_processing_time += bq_processing_time;
2882 globalGranStats.tot_bq_len += len; // total length of all bqs awakened
2883 // globalGranStats.tot_bq_len_local += len_local; // same for local TSOs only
2884 globalGranStats.tot_awbq++; // total no. of bqs awakened
2887 fprintf(stderr,"## BQ Stats of %p: [%d entries] %s\n",
2888 node, len, (bqe!=END_BQ_QUEUE) ? "RBH" : ""));
2892 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2894 StgBlockingQueueElement *bqe;
2896 ACQUIRE_LOCK(&sched_mutex);
2898 IF_PAR_DEBUG(verbose,
2899 belch("##-_ AwBQ for node %p on [%x]: ",
2903 if(get_itbl(q)->type == CONSTR || q==END_BQ_QUEUE) {
2904 IF_PAR_DEBUG(verbose, belch("## ... nothing to unblock so lets just return. RFP (BUG?)"));
2909 ASSERT(q == END_BQ_QUEUE ||
2910 get_itbl(q)->type == TSO ||
2911 get_itbl(q)->type == BLOCKED_FETCH ||
2912 get_itbl(q)->type == CONSTR);
2915 while (get_itbl(bqe)->type==TSO ||
2916 get_itbl(bqe)->type==BLOCKED_FETCH) {
2917 bqe = unblockOneLocked(bqe, node);
2919 RELEASE_LOCK(&sched_mutex);
2922 #else /* !GRAN && !PAR */
2924 awakenBlockedQueue(StgTSO *tso)
2926 ACQUIRE_LOCK(&sched_mutex);
2927 while (tso != END_TSO_QUEUE) {
2928 tso = unblockOneLocked(tso);
2930 RELEASE_LOCK(&sched_mutex);
2934 //@node Exception Handling Routines, Debugging Routines, Blocking Queue Routines, Main scheduling code
2935 //@subsection Exception Handling Routines
2937 /* ---------------------------------------------------------------------------
2939 - usually called inside a signal handler so it mustn't do anything fancy.
2940 ------------------------------------------------------------------------ */
2943 interruptStgRts(void)
2949 /* -----------------------------------------------------------------------------
2952 This is for use when we raise an exception in another thread, which
2954 This has nothing to do with the UnblockThread event in GranSim. -- HWL
2955 -------------------------------------------------------------------------- */
2957 #if defined(GRAN) || defined(PAR)
2959 NB: only the type of the blocking queue is different in GranSim and GUM
2960 the operations on the queue-elements are the same
2961 long live polymorphism!
2963 Locks: sched_mutex is held upon entry and exit.
2967 unblockThread(StgTSO *tso)
2969 StgBlockingQueueElement *t, **last;
2971 switch (tso->why_blocked) {
2974 return; /* not blocked */
2977 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
2979 StgBlockingQueueElement *last_tso = END_BQ_QUEUE;
2980 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
2982 last = (StgBlockingQueueElement **)&mvar->head;
2983 for (t = (StgBlockingQueueElement *)mvar->head;
2985 last = &t->link, last_tso = t, t = t->link) {
2986 if (t == (StgBlockingQueueElement *)tso) {
2987 *last = (StgBlockingQueueElement *)tso->link;
2988 if (mvar->tail == tso) {
2989 mvar->tail = (StgTSO *)last_tso;
2994 barf("unblockThread (MVAR): TSO not found");
2997 case BlockedOnBlackHole:
2998 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
3000 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
3002 last = &bq->blocking_queue;
3003 for (t = bq->blocking_queue;
3005 last = &t->link, t = t->link) {
3006 if (t == (StgBlockingQueueElement *)tso) {
3007 *last = (StgBlockingQueueElement *)tso->link;
3011 barf("unblockThread (BLACKHOLE): TSO not found");
3014 case BlockedOnException:
3016 StgTSO *target = tso->block_info.tso;
3018 ASSERT(get_itbl(target)->type == TSO);
3020 if (target->what_next == ThreadRelocated) {
3021 target = target->link;
3022 ASSERT(get_itbl(target)->type == TSO);
3025 ASSERT(target->blocked_exceptions != NULL);
3027 last = (StgBlockingQueueElement **)&target->blocked_exceptions;
3028 for (t = (StgBlockingQueueElement *)target->blocked_exceptions;
3030 last = &t->link, t = t->link) {
3031 ASSERT(get_itbl(t)->type == TSO);
3032 if (t == (StgBlockingQueueElement *)tso) {
3033 *last = (StgBlockingQueueElement *)tso->link;
3037 barf("unblockThread (Exception): TSO not found");
3041 case BlockedOnWrite:
3043 /* take TSO off blocked_queue */
3044 StgBlockingQueueElement *prev = NULL;
3045 for (t = (StgBlockingQueueElement *)blocked_queue_hd; t != END_BQ_QUEUE;
3046 prev = t, t = t->link) {
3047 if (t == (StgBlockingQueueElement *)tso) {
3049 blocked_queue_hd = (StgTSO *)t->link;
3050 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
3051 blocked_queue_tl = END_TSO_QUEUE;
3054 prev->link = t->link;
3055 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
3056 blocked_queue_tl = (StgTSO *)prev;
3062 barf("unblockThread (I/O): TSO not found");
3065 case BlockedOnDelay:
3067 /* take TSO off sleeping_queue */
3068 StgBlockingQueueElement *prev = NULL;
3069 for (t = (StgBlockingQueueElement *)sleeping_queue; t != END_BQ_QUEUE;
3070 prev = t, t = t->link) {
3071 if (t == (StgBlockingQueueElement *)tso) {
3073 sleeping_queue = (StgTSO *)t->link;
3075 prev->link = t->link;
3080 barf("unblockThread (I/O): TSO not found");
3084 barf("unblockThread");
3088 tso->link = END_TSO_QUEUE;
3089 tso->why_blocked = NotBlocked;
3090 tso->block_info.closure = NULL;
3091 PUSH_ON_RUN_QUEUE(tso);
3095 unblockThread(StgTSO *tso)
3099 /* To avoid locking unnecessarily. */
3100 if (tso->why_blocked == NotBlocked) {
3104 switch (tso->why_blocked) {
3107 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
3109 StgTSO *last_tso = END_TSO_QUEUE;
3110 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
3113 for (t = mvar->head; t != END_TSO_QUEUE;
3114 last = &t->link, last_tso = t, t = t->link) {
3117 if (mvar->tail == tso) {
3118 mvar->tail = last_tso;
3123 barf("unblockThread (MVAR): TSO not found");
3126 case BlockedOnBlackHole:
3127 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
3129 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
3131 last = &bq->blocking_queue;
3132 for (t = bq->blocking_queue; t != END_TSO_QUEUE;
3133 last = &t->link, t = t->link) {
3139 barf("unblockThread (BLACKHOLE): TSO not found");
3142 case BlockedOnException:
3144 StgTSO *target = tso->block_info.tso;
3146 ASSERT(get_itbl(target)->type == TSO);
3148 while (target->what_next == ThreadRelocated) {
3149 target = target->link;
3150 ASSERT(get_itbl(target)->type == TSO);
3153 ASSERT(target->blocked_exceptions != NULL);
3155 last = &target->blocked_exceptions;
3156 for (t = target->blocked_exceptions; t != END_TSO_QUEUE;
3157 last = &t->link, t = t->link) {
3158 ASSERT(get_itbl(t)->type == TSO);
3164 barf("unblockThread (Exception): TSO not found");
3168 case BlockedOnWrite:
3170 StgTSO *prev = NULL;
3171 for (t = blocked_queue_hd; t != END_TSO_QUEUE;
3172 prev = t, t = t->link) {
3175 blocked_queue_hd = t->link;
3176 if (blocked_queue_tl == t) {
3177 blocked_queue_tl = END_TSO_QUEUE;
3180 prev->link = t->link;
3181 if (blocked_queue_tl == t) {
3182 blocked_queue_tl = prev;
3188 barf("unblockThread (I/O): TSO not found");
3191 case BlockedOnDelay:
3193 StgTSO *prev = NULL;
3194 for (t = sleeping_queue; t != END_TSO_QUEUE;
3195 prev = t, t = t->link) {
3198 sleeping_queue = t->link;
3200 prev->link = t->link;
3205 barf("unblockThread (I/O): TSO not found");
3209 barf("unblockThread");
3213 tso->link = END_TSO_QUEUE;
3214 tso->why_blocked = NotBlocked;
3215 tso->block_info.closure = NULL;
3216 PUSH_ON_RUN_QUEUE(tso);
3220 /* -----------------------------------------------------------------------------
3223 * The following function implements the magic for raising an
3224 * asynchronous exception in an existing thread.
3226 * We first remove the thread from any queue on which it might be
3227 * blocked. The possible blockages are MVARs and BLACKHOLE_BQs.
3229 * We strip the stack down to the innermost CATCH_FRAME, building
3230 * thunks in the heap for all the active computations, so they can
3231 * be restarted if necessary. When we reach a CATCH_FRAME, we build
3232 * an application of the handler to the exception, and push it on
3233 * the top of the stack.
3235 * How exactly do we save all the active computations? We create an
3236 * AP_UPD for every UpdateFrame on the stack. Entering one of these
3237 * AP_UPDs pushes everything from the corresponding update frame
3238 * upwards onto the stack. (Actually, it pushes everything up to the
3239 * next update frame plus a pointer to the next AP_UPD object.
3240 * Entering the next AP_UPD object pushes more onto the stack until we
3241 * reach the last AP_UPD object - at which point the stack should look
3242 * exactly as it did when we killed the TSO and we can continue
3243 * execution by entering the closure on top of the stack.
3245 * We can also kill a thread entirely - this happens if either (a) the
3246 * exception passed to raiseAsync is NULL, or (b) there's no
3247 * CATCH_FRAME on the stack. In either case, we strip the entire
3248 * stack and replace the thread with a zombie.
3250 * Locks: sched_mutex held upon entry nor exit.
3252 * -------------------------------------------------------------------------- */
3255 deleteThread(StgTSO *tso)
3257 raiseAsync(tso,NULL);
3261 raiseAsyncWithLock(StgTSO *tso, StgClosure *exception)
3263 /* When raising async exs from contexts where sched_mutex isn't held;
3264 use raiseAsyncWithLock(). */
3265 ACQUIRE_LOCK(&sched_mutex);
3266 raiseAsync(tso,exception);
3267 RELEASE_LOCK(&sched_mutex);
3271 raiseAsync(StgTSO *tso, StgClosure *exception)
3273 StgUpdateFrame* su = tso->su;
3274 StgPtr sp = tso->sp;
3276 /* Thread already dead? */
3277 if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) {
3281 IF_DEBUG(scheduler, sched_belch("raising exception in thread %ld.", tso->id));
3283 /* Remove it from any blocking queues */
3286 /* The stack freezing code assumes there's a closure pointer on
3287 * the top of the stack. This isn't always the case with compiled
3288 * code, so we have to push a dummy closure on the top which just
3289 * returns to the next return address on the stack.
3291 if ( LOOKS_LIKE_GHC_INFO((void*)*sp) ) {
3292 *(--sp) = (W_)&stg_dummy_ret_closure;
3296 nat words = ((P_)su - (P_)sp) - 1;
3300 ASSERT((P_)su > (P_)sp);
3302 /* If we find a CATCH_FRAME, and we've got an exception to raise,
3303 * then build the THUNK raise(exception), and leave it on
3304 * top of the CATCH_FRAME ready to enter.
3306 if (get_itbl(su)->type == CATCH_FRAME && exception != NULL) {
3308 StgCatchFrame *cf = (StgCatchFrame *)su;
3312 /* we've got an exception to raise, so let's pass it to the
3313 * handler in this frame.
3315 raise = (StgClosure *)allocate(sizeofW(StgClosure)+1);
3316 TICK_ALLOC_SE_THK(1,0);
3317 SET_HDR(raise,&stg_raise_info,cf->header.prof.ccs);
3318 raise->payload[0] = exception;
3320 /* throw away the stack from Sp up to the CATCH_FRAME.
3324 /* Ensure that async excpetions are blocked now, so we don't get
3325 * a surprise exception before we get around to executing the
3328 if (tso->blocked_exceptions == NULL) {
3329 tso->blocked_exceptions = END_TSO_QUEUE;
3332 /* Put the newly-built THUNK on top of the stack, ready to execute
3333 * when the thread restarts.
3338 tso->what_next = ThreadEnterGHC;
3339 IF_DEBUG(sanity, checkTSO(tso));
3343 /* First build an AP_UPD consisting of the stack chunk above the
3344 * current update frame, with the top word on the stack as the
3347 ap = (StgAP_UPD *)allocate(AP_sizeW(words));
3350 ap->fun = (StgClosure *)sp[0];
3352 for(i=0; i < (nat)words; ++i) {
3353 ap->payload[i] = (StgClosure *)*sp++;
3356 switch (get_itbl(su)->type) {
3360 SET_HDR(ap,&stg_AP_UPD_info,su->header.prof.ccs /* ToDo */);
3361 TICK_ALLOC_UP_THK(words+1,0);
3364 fprintf(stderr, "scheduler: Updating ");
3365 printPtr((P_)su->updatee);
3366 fprintf(stderr, " with ");
3367 printObj((StgClosure *)ap);
3370 /* Replace the updatee with an indirection - happily
3371 * this will also wake up any threads currently
3372 * waiting on the result.
3374 * Warning: if we're in a loop, more than one update frame on
3375 * the stack may point to the same object. Be careful not to
3376 * overwrite an IND_OLDGEN in this case, because we'll screw
3377 * up the mutable lists. To be on the safe side, don't
3378 * overwrite any kind of indirection at all. See also
3379 * threadSqueezeStack in GC.c, where we have to make a similar
3382 if (!closure_IND(su->updatee)) {
3383 UPD_IND_NOLOCK(su->updatee,ap); /* revert the black hole */
3386 sp += sizeofW(StgUpdateFrame) -1;
3387 sp[0] = (W_)ap; /* push onto stack */
3393 StgCatchFrame *cf = (StgCatchFrame *)su;
3396 /* We want a PAP, not an AP_UPD. Fortunately, the
3397 * layout's the same.
3399 SET_HDR(ap,&stg_PAP_info,su->header.prof.ccs /* ToDo */);
3400 TICK_ALLOC_UPD_PAP(words+1,0);
3402 /* now build o = FUN(catch,ap,handler) */
3403 o = (StgClosure *)allocate(sizeofW(StgClosure)+2);
3404 TICK_ALLOC_FUN(2,0);
3405 SET_HDR(o,&stg_catch_info,su->header.prof.ccs /* ToDo */);
3406 o->payload[0] = (StgClosure *)ap;
3407 o->payload[1] = cf->handler;
3410 fprintf(stderr, "scheduler: Built ");
3411 printObj((StgClosure *)o);
3414 /* pop the old handler and put o on the stack */
3416 sp += sizeofW(StgCatchFrame) - 1;
3423 StgSeqFrame *sf = (StgSeqFrame *)su;
3426 SET_HDR(ap,&stg_PAP_info,su->header.prof.ccs /* ToDo */);
3427 TICK_ALLOC_UPD_PAP(words+1,0);
3429 /* now build o = FUN(seq,ap) */
3430 o = (StgClosure *)allocate(sizeofW(StgClosure)+1);
3431 TICK_ALLOC_SE_THK(1,0);
3432 SET_HDR(o,&stg_seq_info,su->header.prof.ccs /* ToDo */);
3433 o->payload[0] = (StgClosure *)ap;
3436 fprintf(stderr, "scheduler: Built ");
3437 printObj((StgClosure *)o);
3440 /* pop the old handler and put o on the stack */
3442 sp += sizeofW(StgSeqFrame) - 1;
3448 /* We've stripped the entire stack, the thread is now dead. */
3449 sp += sizeofW(StgStopFrame) - 1;
3450 sp[0] = (W_)exception; /* save the exception */
3451 tso->what_next = ThreadKilled;
3452 tso->su = (StgUpdateFrame *)(sp+1);
3463 /* -----------------------------------------------------------------------------
3464 resurrectThreads is called after garbage collection on the list of
3465 threads found to be garbage. Each of these threads will be woken
3466 up and sent a signal: BlockedOnDeadMVar if the thread was blocked
3467 on an MVar, or NonTermination if the thread was blocked on a Black
3470 Locks: sched_mutex isn't held upon entry nor exit.
3471 -------------------------------------------------------------------------- */
3474 resurrectThreads( StgTSO *threads )
3478 for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
3479 next = tso->global_link;
3480 tso->global_link = all_threads;
3482 IF_DEBUG(scheduler, sched_belch("resurrecting thread %d", tso->id));
3484 switch (tso->why_blocked) {
3486 case BlockedOnException:
3487 /* Called by GC - sched_mutex lock is currently held. */
3488 raiseAsync(tso,(StgClosure *)BlockedOnDeadMVar_closure);
3490 case BlockedOnBlackHole:
3491 raiseAsync(tso,(StgClosure *)NonTermination_closure);
3494 /* This might happen if the thread was blocked on a black hole
3495 * belonging to a thread that we've just woken up (raiseAsync
3496 * can wake up threads, remember...).
3500 barf("resurrectThreads: thread blocked in a strange way");
3505 /* -----------------------------------------------------------------------------
3506 * Blackhole detection: if we reach a deadlock, test whether any
3507 * threads are blocked on themselves. Any threads which are found to
3508 * be self-blocked get sent a NonTermination exception.
3510 * This is only done in a deadlock situation in order to avoid
3511 * performance overhead in the normal case.
3513 * Locks: sched_mutex is held upon entry and exit.
3514 * -------------------------------------------------------------------------- */
3517 detectBlackHoles( void )
3519 StgTSO *t = all_threads;
3520 StgUpdateFrame *frame;
3521 StgClosure *blocked_on;
3523 for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
3525 while (t->what_next == ThreadRelocated) {
3527 ASSERT(get_itbl(t)->type == TSO);
3530 if (t->why_blocked != BlockedOnBlackHole) {
3534 blocked_on = t->block_info.closure;
3536 for (frame = t->su; ; frame = frame->link) {
3537 switch (get_itbl(frame)->type) {
3540 if (frame->updatee == blocked_on) {
3541 /* We are blocking on one of our own computations, so
3542 * send this thread the NonTermination exception.
3545 sched_belch("thread %d is blocked on itself", t->id));
3546 raiseAsync(t, (StgClosure *)NonTermination_closure);
3567 //@node Debugging Routines, Index, Exception Handling Routines, Main scheduling code
3568 //@subsection Debugging Routines
3570 /* -----------------------------------------------------------------------------
3571 * Debugging: why is a thread blocked
3572 * [Also provides useful information when debugging threaded programs
3573 * at the Haskell source code level, so enable outside of DEBUG. --sof 7/02]
3574 -------------------------------------------------------------------------- */
3578 printThreadBlockage(StgTSO *tso)
3580 switch (tso->why_blocked) {
3582 fprintf(stderr,"is blocked on read from fd %d", tso->block_info.fd);
3584 case BlockedOnWrite:
3585 fprintf(stderr,"is blocked on write to fd %d", tso->block_info.fd);
3587 case BlockedOnDelay:
3588 fprintf(stderr,"is blocked until %d", tso->block_info.target);
3591 fprintf(stderr,"is blocked on an MVar");
3593 case BlockedOnException:
3594 fprintf(stderr,"is blocked on delivering an exception to thread %d",
3595 tso->block_info.tso->id);
3597 case BlockedOnBlackHole:
3598 fprintf(stderr,"is blocked on a black hole");
3601 fprintf(stderr,"is not blocked");
3605 fprintf(stderr,"is blocked on global address; local FM_BQ is %p (%s)",
3606 tso->block_info.closure, info_type(tso->block_info.closure));
3608 case BlockedOnGA_NoSend:
3609 fprintf(stderr,"is blocked on global address (no send); local FM_BQ is %p (%s)",
3610 tso->block_info.closure, info_type(tso->block_info.closure));
3613 #if defined(RTS_SUPPORTS_THREADS)
3614 case BlockedOnCCall:
3615 fprintf(stderr,"is blocked on an external call");
3619 barf("printThreadBlockage: strange tso->why_blocked: %d for TSO %d (%d)",
3620 tso->why_blocked, tso->id, tso);
3626 printThreadStatus(StgTSO *tso)
3628 switch (tso->what_next) {
3630 fprintf(stderr,"has been killed");
3632 case ThreadComplete:
3633 fprintf(stderr,"has completed");
3636 printThreadBlockage(tso);
3641 printAllThreads(void)
3647 char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN];
3648 ullong_format_string(TIME_ON_PROC(CurrentProc),
3649 time_string, rtsFalse/*no commas!*/);
3651 fprintf(stderr, "all threads at [%s]:\n", time_string);
3653 char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN];
3654 ullong_format_string(CURRENT_TIME,
3655 time_string, rtsFalse/*no commas!*/);
3657 fprintf(stderr,"all threads at [%s]:\n", time_string);
3659 fprintf(stderr,"all threads:\n");
3662 for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
3663 fprintf(stderr, "\tthread %d @ %p ", t->id, (void *)t);
3664 label = lookupThreadLabel((StgWord)t);
3665 if (label) fprintf(stderr,"[\"%s\"] ",(char *)label);
3666 printThreadStatus(t);
3667 fprintf(stderr,"\n");
3674 Print a whole blocking queue attached to node (debugging only).
3679 print_bq (StgClosure *node)
3681 StgBlockingQueueElement *bqe;
3685 fprintf(stderr,"## BQ of closure %p (%s): ",
3686 node, info_type(node));
3688 /* should cover all closures that may have a blocking queue */
3689 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3690 get_itbl(node)->type == FETCH_ME_BQ ||
3691 get_itbl(node)->type == RBH ||
3692 get_itbl(node)->type == MVAR);
3694 ASSERT(node!=(StgClosure*)NULL); // sanity check
3696 print_bqe(((StgBlockingQueue*)node)->blocking_queue);
3700 Print a whole blocking queue starting with the element bqe.
3703 print_bqe (StgBlockingQueueElement *bqe)
3708 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3710 for (end = (bqe==END_BQ_QUEUE);
3711 !end; // iterate until bqe points to a CONSTR
3712 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE),
3713 bqe = end ? END_BQ_QUEUE : bqe->link) {
3714 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3715 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
3716 /* types of closures that may appear in a blocking queue */
3717 ASSERT(get_itbl(bqe)->type == TSO ||
3718 get_itbl(bqe)->type == BLOCKED_FETCH ||
3719 get_itbl(bqe)->type == CONSTR);
3720 /* only BQs of an RBH end with an RBH_Save closure */
3721 //ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3723 switch (get_itbl(bqe)->type) {
3725 fprintf(stderr," TSO %u (%x),",
3726 ((StgTSO *)bqe)->id, ((StgTSO *)bqe));
3729 fprintf(stderr," BF (node=%p, ga=((%x, %d, %x)),",
3730 ((StgBlockedFetch *)bqe)->node,
3731 ((StgBlockedFetch *)bqe)->ga.payload.gc.gtid,
3732 ((StgBlockedFetch *)bqe)->ga.payload.gc.slot,
3733 ((StgBlockedFetch *)bqe)->ga.weight);
3736 fprintf(stderr," %s (IP %p),",
3737 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3738 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3739 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3740 "RBH_Save_?"), get_itbl(bqe));
3743 barf("Unexpected closure type %s in blocking queue", // of %p (%s)",
3744 info_type((StgClosure *)bqe)); // , node, info_type(node));
3748 fputc('\n', stderr);
3750 # elif defined(GRAN)
3752 print_bq (StgClosure *node)
3754 StgBlockingQueueElement *bqe;
3755 PEs node_loc, tso_loc;
3758 /* should cover all closures that may have a blocking queue */
3759 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3760 get_itbl(node)->type == FETCH_ME_BQ ||
3761 get_itbl(node)->type == RBH);
3763 ASSERT(node!=(StgClosure*)NULL); // sanity check
3764 node_loc = where_is(node);
3766 fprintf(stderr,"## BQ of closure %p (%s) on [PE %d]: ",
3767 node, info_type(node), node_loc);
3770 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3772 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
3773 !end; // iterate until bqe points to a CONSTR
3774 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
3775 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3776 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
3777 /* types of closures that may appear in a blocking queue */
3778 ASSERT(get_itbl(bqe)->type == TSO ||
3779 get_itbl(bqe)->type == CONSTR);
3780 /* only BQs of an RBH end with an RBH_Save closure */
3781 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3783 tso_loc = where_is((StgClosure *)bqe);
3784 switch (get_itbl(bqe)->type) {
3786 fprintf(stderr," TSO %d (%p) on [PE %d],",
3787 ((StgTSO *)bqe)->id, (StgTSO *)bqe, tso_loc);
3790 fprintf(stderr," %s (IP %p),",
3791 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3792 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3793 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3794 "RBH_Save_?"), get_itbl(bqe));
3797 barf("Unexpected closure type %s in blocking queue of %p (%s)",
3798 info_type((StgClosure *)bqe), node, info_type(node));
3802 fputc('\n', stderr);
3806 Nice and easy: only TSOs on the blocking queue
3809 print_bq (StgClosure *node)
3813 ASSERT(node!=(StgClosure*)NULL); // sanity check
3814 for (tso = ((StgBlockingQueue*)node)->blocking_queue;
3815 tso != END_TSO_QUEUE;
3817 ASSERT(tso!=NULL && tso!=END_TSO_QUEUE); // sanity check
3818 ASSERT(get_itbl(tso)->type == TSO); // guess what, sanity check
3819 fprintf(stderr," TSO %d (%p),", tso->id, tso);
3821 fputc('\n', stderr);
3832 for (i=0, tso=run_queue_hd;
3833 tso != END_TSO_QUEUE;
3842 sched_belch(char *s, ...)
3847 fprintf(stderr, "scheduler (task %ld): ", osThreadId());
3849 fprintf(stderr, "== ");
3851 fprintf(stderr, "scheduler: ");
3853 vfprintf(stderr, s, ap);
3854 fprintf(stderr, "\n");
3861 //@node Index, , Debugging Routines, Main scheduling code
3865 //* StgMainThread:: @cindex\s-+StgMainThread
3866 //* awaken_blocked_queue:: @cindex\s-+awaken_blocked_queue
3867 //* blocked_queue_hd:: @cindex\s-+blocked_queue_hd
3868 //* blocked_queue_tl:: @cindex\s-+blocked_queue_tl
3869 //* context_switch:: @cindex\s-+context_switch
3870 //* createThread:: @cindex\s-+createThread
3871 //* gc_pending_cond:: @cindex\s-+gc_pending_cond
3872 //* initScheduler:: @cindex\s-+initScheduler
3873 //* interrupted:: @cindex\s-+interrupted
3874 //* next_thread_id:: @cindex\s-+next_thread_id
3875 //* print_bq:: @cindex\s-+print_bq
3876 //* run_queue_hd:: @cindex\s-+run_queue_hd
3877 //* run_queue_tl:: @cindex\s-+run_queue_tl
3878 //* sched_mutex:: @cindex\s-+sched_mutex
3879 //* schedule:: @cindex\s-+schedule
3880 //* take_off_run_queue:: @cindex\s-+take_off_run_queue
3881 //* term_mutex:: @cindex\s-+term_mutex