1 /* ---------------------------------------------------------------------------
2 * $Id: Schedule.c,v 1.161 2003/01/25 15:54:49 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 // Pointer to the thread that executes main
140 // When this thread is finished, the program terminates
141 // by calling shutdownHaskellAndExit.
142 // It would be better to add a call to shutdownHaskellAndExit
143 // to the Main.main wrapper and to remove this hack.
144 StgMainThread *main_main_thread = NULL;
148 * Locks required: sched_mutex.
152 StgTSO* ActiveTSO = NULL; /* for assigning system costs; GranSim-Light only */
153 /* rtsTime TimeOfNextEvent, EndOfTimeSlice; now in GranSim.c */
156 In GranSim we have a runnable and a blocked queue for each processor.
157 In order to minimise code changes new arrays run_queue_hds/tls
158 are created. run_queue_hd is then a short cut (macro) for
159 run_queue_hds[CurrentProc] (see GranSim.h).
162 StgTSO *run_queue_hds[MAX_PROC], *run_queue_tls[MAX_PROC];
163 StgTSO *blocked_queue_hds[MAX_PROC], *blocked_queue_tls[MAX_PROC];
164 StgTSO *ccalling_threadss[MAX_PROC];
165 /* We use the same global list of threads (all_threads) in GranSim as in
166 the std RTS (i.e. we are cheating). However, we don't use this list in
167 the GranSim specific code at the moment (so we are only potentially
172 StgTSO *run_queue_hd = NULL;
173 StgTSO *run_queue_tl = NULL;
174 StgTSO *blocked_queue_hd = NULL;
175 StgTSO *blocked_queue_tl = NULL;
176 StgTSO *sleeping_queue = NULL; /* perhaps replace with a hash table? */
180 /* Linked list of all threads.
181 * Used for detecting garbage collected threads.
183 StgTSO *all_threads = NULL;
185 /* When a thread performs a safe C call (_ccall_GC, using old
186 * terminology), it gets put on the suspended_ccalling_threads
187 * list. Used by the garbage collector.
189 static StgTSO *suspended_ccalling_threads;
191 static StgTSO *threadStackOverflow(StgTSO *tso);
193 /* KH: The following two flags are shared memory locations. There is no need
194 to lock them, since they are only unset at the end of a scheduler
198 /* flag set by signal handler to precipitate a context switch */
199 //@cindex context_switch
200 nat context_switch = 0;
202 /* if this flag is set as well, give up execution */
203 //@cindex interrupted
204 rtsBool interrupted = rtsFalse;
206 /* Next thread ID to allocate.
207 * Locks required: thread_id_mutex
209 //@cindex next_thread_id
210 static StgThreadID next_thread_id = 1;
213 * Pointers to the state of the current thread.
214 * Rule of thumb: if CurrentTSO != NULL, then we're running a Haskell
215 * thread. If CurrentTSO == NULL, then we're at the scheduler level.
218 /* The smallest stack size that makes any sense is:
219 * RESERVED_STACK_WORDS (so we can get back from the stack overflow)
220 * + sizeofW(StgStopFrame) (the stg_stop_thread_info frame)
221 * + 1 (the realworld token for an IO thread)
222 * + 1 (the closure to enter)
224 * A thread with this stack will bomb immediately with a stack
225 * overflow, which will increase its stack size.
228 #define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 2)
235 /* This is used in `TSO.h' and gcc 2.96 insists that this variable actually
236 * exists - earlier gccs apparently didn't.
241 static rtsBool ready_to_gc;
244 * Set to TRUE when entering a shutdown state (via shutdownHaskellAndExit()) --
245 * in an MT setting, needed to signal that a worker thread shouldn't hang around
246 * in the scheduler when it is out of work.
248 static rtsBool shutting_down_scheduler = rtsFalse;
250 void addToBlockedQueue ( StgTSO *tso );
252 static void schedule ( void );
253 void interruptStgRts ( void );
255 static void detectBlackHoles ( void );
258 static void sched_belch(char *s, ...);
261 #if defined(RTS_SUPPORTS_THREADS)
262 /* ToDo: carefully document the invariants that go together
263 * with these synchronisation objects.
265 Mutex sched_mutex = INIT_MUTEX_VAR;
266 Mutex term_mutex = INIT_MUTEX_VAR;
269 * A heavyweight solution to the problem of protecting
270 * the thread_id from concurrent update.
272 Mutex thread_id_mutex = INIT_MUTEX_VAR;
276 static Condition gc_pending_cond = INIT_COND_VAR;
280 #endif /* RTS_SUPPORTS_THREADS */
284 rtsTime TimeOfLastYield;
285 rtsBool emitSchedule = rtsTrue;
289 static char *whatNext_strs[] = {
299 StgTSO * createSparkThread(rtsSpark spark);
300 StgTSO * activateSpark (rtsSpark spark);
304 * The thread state for the main thread.
305 // ToDo: check whether not needed any more
309 #if defined(PAR) || defined(RTS_SUPPORTS_THREADS)
310 static void taskStart(void);
318 #if defined(RTS_SUPPORTS_THREADS)
320 startSchedulerTask(void)
322 startTask(taskStart);
326 //@node Main scheduling loop, Suspend and Resume, Prototypes, Main scheduling code
327 //@subsection Main scheduling loop
329 /* ---------------------------------------------------------------------------
330 Main scheduling loop.
332 We use round-robin scheduling, each thread returning to the
333 scheduler loop when one of these conditions is detected:
336 * timer expires (thread yields)
341 Locking notes: we acquire the scheduler lock once at the beginning
342 of the scheduler loop, and release it when
344 * running a thread, or
345 * waiting for work, or
346 * waiting for a GC to complete.
349 In a GranSim setup this loop iterates over the global event queue.
350 This revolves around the global event queue, which determines what
351 to do next. Therefore, it's more complicated than either the
352 concurrent or the parallel (GUM) setup.
355 GUM iterates over incoming messages.
356 It starts with nothing to do (thus CurrentTSO == END_TSO_QUEUE),
357 and sends out a fish whenever it has nothing to do; in-between
358 doing the actual reductions (shared code below) it processes the
359 incoming messages and deals with delayed operations
360 (see PendingFetches).
361 This is not the ugliest code you could imagine, but it's bloody close.
363 ------------------------------------------------------------------------ */
370 StgThreadReturnCode ret;
378 rtsBool receivedFinish = rtsFalse;
380 nat tp_size, sp_size; // stats only
383 rtsBool was_interrupted = rtsFalse;
384 StgTSOWhatNext prev_what_next;
386 ACQUIRE_LOCK(&sched_mutex);
388 #if defined(RTS_SUPPORTS_THREADS)
389 waitForWorkCapability(&sched_mutex, &cap, rtsFalse);
390 IF_DEBUG(scheduler, sched_belch("worker thread (osthread %p): entering RTS", osThreadId()));
392 /* simply initialise it in the non-threaded case */
393 grabCapability(&cap);
397 /* set up first event to get things going */
398 /* ToDo: assign costs for system setup and init MainTSO ! */
399 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
401 CurrentTSO, (StgClosure*)NULL, (rtsSpark*)NULL);
404 fprintf(stderr, "GRAN: Init CurrentTSO (in schedule) = %p\n", CurrentTSO);
405 G_TSO(CurrentTSO, 5));
407 if (RtsFlags.GranFlags.Light) {
408 /* Save current time; GranSim Light only */
409 CurrentTSO->gran.clock = CurrentTime[CurrentProc];
412 event = get_next_event();
414 while (event!=(rtsEvent*)NULL) {
415 /* Choose the processor with the next event */
416 CurrentProc = event->proc;
417 CurrentTSO = event->tso;
421 while (!receivedFinish) { /* set by processMessages */
422 /* when receiving PP_FINISH message */
429 IF_DEBUG(scheduler, printAllThreads());
431 #if defined(RTS_SUPPORTS_THREADS)
432 /* Check to see whether there are any worker threads
433 waiting to deposit external call results. If so,
434 yield our capability */
435 yieldToReturningWorker(&sched_mutex, &cap);
438 /* If we're interrupted (the user pressed ^C, or some other
439 * termination condition occurred), kill all the currently running
443 IF_DEBUG(scheduler, sched_belch("interrupted"));
444 interrupted = rtsFalse;
445 was_interrupted = rtsTrue;
446 #if defined(RTS_SUPPORTS_THREADS)
447 // In the threaded RTS, deadlock detection doesn't work,
448 // so just exit right away.
449 prog_belch("interrupted");
450 releaseCapability(cap);
451 startTask(taskStart); // thread-safe-call to shutdownHaskellAndExit
452 RELEASE_LOCK(&sched_mutex);
453 shutdownHaskellAndExit(EXIT_SUCCESS);
459 /* Go through the list of main threads and wake up any
460 * clients whose computations have finished. ToDo: this
461 * should be done more efficiently without a linear scan
462 * of the main threads list, somehow...
464 #if defined(RTS_SUPPORTS_THREADS)
466 StgMainThread *m, **prev;
467 prev = &main_threads;
468 for (m = main_threads; m != NULL; prev = &m->link, m = m->link) {
469 switch (m->tso->what_next) {
472 // NOTE: return val is tso->sp[1] (see StgStartup.hc)
473 *(m->ret) = (StgClosure *)m->tso->sp[1];
477 broadcastCondition(&m->wakeup);
479 removeThreadLabel((StgWord)m->tso);
481 if(m == main_main_thread)
483 releaseCapability(cap);
484 startTask(taskStart); // thread-safe-call to shutdownHaskellAndExit
485 RELEASE_LOCK(&sched_mutex);
486 shutdownHaskellAndExit(EXIT_SUCCESS);
490 if (m->ret) *(m->ret) = NULL;
492 if (was_interrupted) {
493 m->stat = Interrupted;
497 broadcastCondition(&m->wakeup);
499 removeThreadLabel((StgWord)m->tso);
501 if(m == main_main_thread)
503 releaseCapability(cap);
504 startTask(taskStart); // thread-safe-call to shutdownHaskellAndExit
505 RELEASE_LOCK(&sched_mutex);
506 shutdownHaskellAndExit(EXIT_SUCCESS);
515 #else /* not threaded */
518 /* in GUM do this only on the Main PE */
521 /* If our main thread has finished or been killed, return.
524 StgMainThread *m = main_threads;
525 if (m->tso->what_next == ThreadComplete
526 || m->tso->what_next == ThreadKilled) {
528 removeThreadLabel((StgWord)m->tso);
530 main_threads = main_threads->link;
531 if (m->tso->what_next == ThreadComplete) {
532 // We finished successfully, fill in the return value
533 // NOTE: return val is tso->sp[1] (see StgStartup.hc)
534 if (m->ret) { *(m->ret) = (StgClosure *)m->tso->sp[1]; };
538 if (m->ret) { *(m->ret) = NULL; };
539 if (was_interrupted) {
540 m->stat = Interrupted;
550 /* Top up the run queue from our spark pool. We try to make the
551 * number of threads in the run queue equal to the number of
554 * Disable spark support in SMP for now, non-essential & requires
555 * a little bit of work to make it compile cleanly. -- sof 1/02.
557 #if 0 /* defined(SMP) */
559 nat n = getFreeCapabilities();
560 StgTSO *tso = run_queue_hd;
562 /* Count the run queue */
563 while (n > 0 && tso != END_TSO_QUEUE) {
570 spark = findSpark(rtsFalse);
572 break; /* no more sparks in the pool */
574 /* I'd prefer this to be done in activateSpark -- HWL */
575 /* tricky - it needs to hold the scheduler lock and
576 * not try to re-acquire it -- SDM */
577 createSparkThread(spark);
579 sched_belch("==^^ turning spark of closure %p into a thread",
580 (StgClosure *)spark));
583 /* We need to wake up the other tasks if we just created some
586 if (getFreeCapabilities() - n > 1) {
587 signalCondition( &thread_ready_cond );
592 /* check for signals each time around the scheduler */
593 #ifndef mingw32_TARGET_OS
594 if (signals_pending()) {
595 RELEASE_LOCK(&sched_mutex); /* ToDo: kill */
596 startSignalHandlers();
597 ACQUIRE_LOCK(&sched_mutex);
601 /* Check whether any waiting threads need to be woken up. If the
602 * run queue is empty, and there are no other tasks running, we
603 * can wait indefinitely for something to happen.
605 if ( !EMPTY_QUEUE(blocked_queue_hd) || !EMPTY_QUEUE(sleeping_queue)
606 #if defined(RTS_SUPPORTS_THREADS) && !defined(SMP)
611 awaitEvent( EMPTY_RUN_QUEUE()
613 && allFreeCapabilities()
617 /* we can be interrupted while waiting for I/O... */
618 if (interrupted) continue;
621 * Detect deadlock: when we have no threads to run, there are no
622 * threads waiting on I/O or sleeping, and all the other tasks are
623 * waiting for work, we must have a deadlock of some description.
625 * We first try to find threads blocked on themselves (ie. black
626 * holes), and generate NonTermination exceptions where necessary.
628 * If no threads are black holed, we have a deadlock situation, so
629 * inform all the main threads.
631 #if !defined(PAR) && !defined(RTS_SUPPORTS_THREADS)
632 if ( EMPTY_THREAD_QUEUES()
633 #if defined(RTS_SUPPORTS_THREADS)
634 && EMPTY_QUEUE(suspended_ccalling_threads)
637 && allFreeCapabilities()
641 IF_DEBUG(scheduler, sched_belch("deadlocked, forcing major GC..."));
642 #if defined(THREADED_RTS)
643 /* and SMP mode ..? */
644 releaseCapability(cap);
646 // Garbage collection can release some new threads due to
647 // either (a) finalizers or (b) threads resurrected because
648 // they are about to be send BlockedOnDeadMVar. Any threads
649 // thus released will be immediately runnable.
650 GarbageCollect(GetRoots,rtsTrue);
652 if ( !EMPTY_RUN_QUEUE() ) { goto not_deadlocked; }
655 sched_belch("still deadlocked, checking for black holes..."));
658 if ( !EMPTY_RUN_QUEUE() ) { goto not_deadlocked; }
660 #ifndef mingw32_TARGET_OS
661 /* If we have user-installed signal handlers, then wait
662 * for signals to arrive rather then bombing out with a
665 #if defined(RTS_SUPPORTS_THREADS)
666 if ( 0 ) { /* hmm..what to do? Simply stop waiting for
667 a signal with no runnable threads (or I/O
668 suspended ones) leads nowhere quick.
669 For now, simply shut down when we reach this
672 ToDo: define precisely under what conditions
673 the Scheduler should shut down in an MT setting.
676 if ( anyUserHandlers() ) {
679 sched_belch("still deadlocked, waiting for signals..."));
683 // we might be interrupted...
684 if (interrupted) { continue; }
686 if (signals_pending()) {
687 RELEASE_LOCK(&sched_mutex);
688 startSignalHandlers();
689 ACQUIRE_LOCK(&sched_mutex);
691 ASSERT(!EMPTY_RUN_QUEUE());
696 /* Probably a real deadlock. Send the current main thread the
697 * Deadlock exception (or in the SMP build, send *all* main
698 * threads the deadlock exception, since none of them can make
703 #if defined(RTS_SUPPORTS_THREADS)
704 for (m = main_threads; m != NULL; m = m->link) {
705 switch (m->tso->why_blocked) {
706 case BlockedOnBlackHole:
707 raiseAsync(m->tso, (StgClosure *)NonTermination_closure);
709 case BlockedOnException:
711 raiseAsync(m->tso, (StgClosure *)Deadlock_closure);
714 barf("deadlock: main thread blocked in a strange way");
719 switch (m->tso->why_blocked) {
720 case BlockedOnBlackHole:
721 raiseAsync(m->tso, (StgClosure *)NonTermination_closure);
723 case BlockedOnException:
725 raiseAsync(m->tso, (StgClosure *)Deadlock_closure);
728 barf("deadlock: main thread blocked in a strange way");
733 #if defined(RTS_SUPPORTS_THREADS)
734 /* ToDo: revisit conditions (and mechanism) for shutting
735 down a multi-threaded world */
736 IF_DEBUG(scheduler, sched_belch("all done, i think...shutting down."));
737 RELEASE_LOCK(&sched_mutex);
744 #elif defined(RTS_SUPPORTS_THREADS)
745 /* ToDo: add deadlock detection in threaded RTS */
747 /* ToDo: add deadlock detection in GUM (similar to SMP) -- HWL */
751 /* If there's a GC pending, don't do anything until it has
755 IF_DEBUG(scheduler,sched_belch("waiting for GC"));
756 waitCondition( &gc_pending_cond, &sched_mutex );
760 #if defined(RTS_SUPPORTS_THREADS)
762 /* block until we've got a thread on the run queue and a free
766 if ( EMPTY_RUN_QUEUE() ) {
767 /* Give up our capability */
768 releaseCapability(cap);
770 /* If we're in the process of shutting down (& running the
771 * a batch of finalisers), don't wait around.
773 if ( shutting_down_scheduler ) {
774 RELEASE_LOCK(&sched_mutex);
777 IF_DEBUG(scheduler, sched_belch("thread %d: waiting for work", osThreadId()));
778 waitForWorkCapability(&sched_mutex, &cap, rtsTrue);
779 IF_DEBUG(scheduler, sched_belch("thread %d: work now available", osThreadId()));
782 if ( EMPTY_RUN_QUEUE() ) {
783 continue; // nothing to do
789 if (RtsFlags.GranFlags.Light)
790 GranSimLight_enter_system(event, &ActiveTSO); // adjust ActiveTSO etc
792 /* adjust time based on time-stamp */
793 if (event->time > CurrentTime[CurrentProc] &&
794 event->evttype != ContinueThread)
795 CurrentTime[CurrentProc] = event->time;
797 /* Deal with the idle PEs (may issue FindWork or MoveSpark events) */
798 if (!RtsFlags.GranFlags.Light)
801 IF_DEBUG(gran, fprintf(stderr, "GRAN: switch by event-type\n"));
803 /* main event dispatcher in GranSim */
804 switch (event->evttype) {
805 /* Should just be continuing execution */
807 IF_DEBUG(gran, fprintf(stderr, "GRAN: doing ContinueThread\n"));
808 /* ToDo: check assertion
809 ASSERT(run_queue_hd != (StgTSO*)NULL &&
810 run_queue_hd != END_TSO_QUEUE);
812 /* Ignore ContinueThreads for fetching threads (if synchr comm) */
813 if (!RtsFlags.GranFlags.DoAsyncFetch &&
814 procStatus[CurrentProc]==Fetching) {
815 belch("ghuH: Spurious ContinueThread while Fetching ignored; TSO %d (%p) [PE %d]",
816 CurrentTSO->id, CurrentTSO, CurrentProc);
819 /* Ignore ContinueThreads for completed threads */
820 if (CurrentTSO->what_next == ThreadComplete) {
821 belch("ghuH: found a ContinueThread event for completed thread %d (%p) [PE %d] (ignoring ContinueThread)",
822 CurrentTSO->id, CurrentTSO, CurrentProc);
825 /* Ignore ContinueThreads for threads that are being migrated */
826 if (PROCS(CurrentTSO)==Nowhere) {
827 belch("ghuH: trying to run the migrating TSO %d (%p) [PE %d] (ignoring ContinueThread)",
828 CurrentTSO->id, CurrentTSO, CurrentProc);
831 /* The thread should be at the beginning of the run queue */
832 if (CurrentTSO!=run_queue_hds[CurrentProc]) {
833 belch("ghuH: TSO %d (%p) [PE %d] is not at the start of the run_queue when doing a ContinueThread",
834 CurrentTSO->id, CurrentTSO, CurrentProc);
835 break; // run the thread anyway
838 new_event(proc, proc, CurrentTime[proc],
840 (StgTSO*)NULL, (StgClosure*)NULL, (rtsSpark*)NULL);
842 */ /* Catches superfluous CONTINUEs -- should be unnecessary */
843 break; // now actually run the thread; DaH Qu'vam yImuHbej
846 do_the_fetchnode(event);
847 goto next_thread; /* handle next event in event queue */
850 do_the_globalblock(event);
851 goto next_thread; /* handle next event in event queue */
854 do_the_fetchreply(event);
855 goto next_thread; /* handle next event in event queue */
857 case UnblockThread: /* Move from the blocked queue to the tail of */
858 do_the_unblock(event);
859 goto next_thread; /* handle next event in event queue */
861 case ResumeThread: /* Move from the blocked queue to the tail of */
862 /* the runnable queue ( i.e. Qu' SImqa'lu') */
863 event->tso->gran.blocktime +=
864 CurrentTime[CurrentProc] - event->tso->gran.blockedat;
865 do_the_startthread(event);
866 goto next_thread; /* handle next event in event queue */
869 do_the_startthread(event);
870 goto next_thread; /* handle next event in event queue */
873 do_the_movethread(event);
874 goto next_thread; /* handle next event in event queue */
877 do_the_movespark(event);
878 goto next_thread; /* handle next event in event queue */
881 do_the_findwork(event);
882 goto next_thread; /* handle next event in event queue */
885 barf("Illegal event type %u\n", event->evttype);
888 /* This point was scheduler_loop in the old RTS */
890 IF_DEBUG(gran, belch("GRAN: after main switch"));
892 TimeOfLastEvent = CurrentTime[CurrentProc];
893 TimeOfNextEvent = get_time_of_next_event();
894 IgnoreEvents=(TimeOfNextEvent==0); // HWL HACK
895 // CurrentTSO = ThreadQueueHd;
897 IF_DEBUG(gran, belch("GRAN: time of next event is: %ld",
900 if (RtsFlags.GranFlags.Light)
901 GranSimLight_leave_system(event, &ActiveTSO);
903 EndOfTimeSlice = CurrentTime[CurrentProc]+RtsFlags.GranFlags.time_slice;
906 belch("GRAN: end of time-slice is %#lx", EndOfTimeSlice));
908 /* in a GranSim setup the TSO stays on the run queue */
910 /* Take a thread from the run queue. */
911 t = POP_RUN_QUEUE(); // take_off_run_queue(t);
914 fprintf(stderr, "GRAN: About to run current thread, which is\n");
917 context_switch = 0; // turned on via GranYield, checking events and time slice
920 DumpGranEvent(GR_SCHEDULE, t));
922 procStatus[CurrentProc] = Busy;
925 if (PendingFetches != END_BF_QUEUE) {
929 /* ToDo: phps merge with spark activation above */
930 /* check whether we have local work and send requests if we have none */
931 if (EMPTY_RUN_QUEUE()) { /* no runnable threads */
932 /* :-[ no local threads => look out for local sparks */
933 /* the spark pool for the current PE */
934 pool = &(MainRegTable.rSparks); // generalise to cap = &MainRegTable
935 if (advisory_thread_count < RtsFlags.ParFlags.maxThreads &&
936 pool->hd < pool->tl) {
938 * ToDo: add GC code check that we really have enough heap afterwards!!
940 * If we're here (no runnable threads) and we have pending
941 * sparks, we must have a space problem. Get enough space
942 * to turn one of those pending sparks into a
946 spark = findSpark(rtsFalse); /* get a spark */
947 if (spark != (rtsSpark) NULL) {
948 tso = activateSpark(spark); /* turn the spark into a thread */
949 IF_PAR_DEBUG(schedule,
950 belch("==== schedule: Created TSO %d (%p); %d threads active",
951 tso->id, tso, advisory_thread_count));
953 if (tso==END_TSO_QUEUE) { /* failed to activate spark->back to loop */
954 belch("==^^ failed to activate spark");
956 } /* otherwise fall through & pick-up new tso */
958 IF_PAR_DEBUG(verbose,
959 belch("==^^ no local sparks (spark pool contains only NFs: %d)",
960 spark_queue_len(pool)));
965 /* If we still have no work we need to send a FISH to get a spark
968 if (EMPTY_RUN_QUEUE()) {
969 /* =8-[ no local sparks => look for work on other PEs */
971 * We really have absolutely no work. Send out a fish
972 * (there may be some out there already), and wait for
973 * something to arrive. We clearly can't run any threads
974 * until a SCHEDULE or RESUME arrives, and so that's what
975 * we're hoping to see. (Of course, we still have to
976 * respond to other types of messages.)
978 TIME now = msTime() /*CURRENT_TIME*/;
979 IF_PAR_DEBUG(verbose,
980 belch("-- now=%ld", now));
981 IF_PAR_DEBUG(verbose,
982 if (outstandingFishes < RtsFlags.ParFlags.maxFishes &&
983 (last_fish_arrived_at!=0 &&
984 last_fish_arrived_at+RtsFlags.ParFlags.fishDelay > now)) {
985 belch("--$$ delaying FISH until %ld (last fish %ld, delay %ld, now %ld)",
986 last_fish_arrived_at+RtsFlags.ParFlags.fishDelay,
987 last_fish_arrived_at,
988 RtsFlags.ParFlags.fishDelay, now);
991 if (outstandingFishes < RtsFlags.ParFlags.maxFishes &&
992 (last_fish_arrived_at==0 ||
993 (last_fish_arrived_at+RtsFlags.ParFlags.fishDelay <= now))) {
994 /* outstandingFishes is set in sendFish, processFish;
995 avoid flooding system with fishes via delay */
997 sendFish(pe, mytid, NEW_FISH_AGE, NEW_FISH_HISTORY,
1000 // Global statistics: count no. of fishes
1001 if (RtsFlags.ParFlags.ParStats.Global &&
1002 RtsFlags.GcFlags.giveStats > NO_GC_STATS) {
1003 globalParStats.tot_fish_mess++;
1007 receivedFinish = processMessages();
1010 } else if (PacketsWaiting()) { /* Look for incoming messages */
1011 receivedFinish = processMessages();
1014 /* Now we are sure that we have some work available */
1015 ASSERT(run_queue_hd != END_TSO_QUEUE);
1017 /* Take a thread from the run queue, if we have work */
1018 t = POP_RUN_QUEUE(); // take_off_run_queue(END_TSO_QUEUE);
1019 IF_DEBUG(sanity,checkTSO(t));
1021 /* ToDo: write something to the log-file
1022 if (RTSflags.ParFlags.granSimStats && !sameThread)
1023 DumpGranEvent(GR_SCHEDULE, RunnableThreadsHd);
1027 /* the spark pool for the current PE */
1028 pool = &(MainRegTable.rSparks); // generalise to cap = &MainRegTable
1031 belch("--=^ %d threads, %d sparks on [%#x]",
1032 run_queue_len(), spark_queue_len(pool), CURRENT_PROC));
1035 if (0 && RtsFlags.ParFlags.ParStats.Full &&
1036 t && LastTSO && t->id != LastTSO->id &&
1037 LastTSO->why_blocked == NotBlocked &&
1038 LastTSO->what_next != ThreadComplete) {
1039 // if previously scheduled TSO not blocked we have to record the context switch
1040 DumpVeryRawGranEvent(TimeOfLastYield, CURRENT_PROC, CURRENT_PROC,
1041 GR_DESCHEDULE, LastTSO, (StgClosure *)NULL, 0, 0);
1044 if (RtsFlags.ParFlags.ParStats.Full &&
1045 (emitSchedule /* forced emit */ ||
1046 (t && LastTSO && t->id != LastTSO->id))) {
1048 we are running a different TSO, so write a schedule event to log file
1049 NB: If we use fair scheduling we also have to write a deschedule
1050 event for LastTSO; with unfair scheduling we know that the
1051 previous tso has blocked whenever we switch to another tso, so
1052 we don't need it in GUM for now
1054 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
1055 GR_SCHEDULE, t, (StgClosure *)NULL, 0, 0);
1056 emitSchedule = rtsFalse;
1060 #else /* !GRAN && !PAR */
1062 /* grab a thread from the run queue */
1063 ASSERT(run_queue_hd != END_TSO_QUEUE);
1064 t = POP_RUN_QUEUE();
1065 // Sanity check the thread we're about to run. This can be
1066 // expensive if there is lots of thread switching going on...
1067 IF_DEBUG(sanity,checkTSO(t));
1070 cap->r.rCurrentTSO = t;
1072 /* context switches are now initiated by the timer signal, unless
1073 * the user specified "context switch as often as possible", with
1076 if ((RtsFlags.ConcFlags.ctxtSwitchTicks == 0
1077 && (run_queue_hd != END_TSO_QUEUE
1078 || blocked_queue_hd != END_TSO_QUEUE
1079 || sleeping_queue != END_TSO_QUEUE)))
1086 RELEASE_LOCK(&sched_mutex);
1088 IF_DEBUG(scheduler, sched_belch("-->> running thread %ld %s ...",
1089 t->id, whatNext_strs[t->what_next]));
1092 startHeapProfTimer();
1095 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
1096 /* Run the current thread
1098 prev_what_next = t->what_next;
1099 switch (prev_what_next) {
1101 case ThreadComplete:
1102 /* Thread already finished, return to scheduler. */
1103 ret = ThreadFinished;
1106 ret = StgRun((StgFunPtr) stg_returnToStackTop, &cap->r);
1108 case ThreadInterpret:
1109 ret = interpretBCO(cap);
1112 barf("schedule: invalid what_next field");
1114 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
1116 /* Costs for the scheduler are assigned to CCS_SYSTEM */
1118 stopHeapProfTimer();
1122 ACQUIRE_LOCK(&sched_mutex);
1124 #ifdef RTS_SUPPORTS_THREADS
1125 IF_DEBUG(scheduler,fprintf(stderr,"scheduler (task %ld): ", osThreadId()););
1126 #elif !defined(GRAN) && !defined(PAR)
1127 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: "););
1129 t = cap->r.rCurrentTSO;
1132 /* HACK 675: if the last thread didn't yield, make sure to print a
1133 SCHEDULE event to the log file when StgRunning the next thread, even
1134 if it is the same one as before */
1136 TimeOfLastYield = CURRENT_TIME;
1142 IF_DEBUG(gran, DumpGranEvent(GR_DESCHEDULE, t));
1143 globalGranStats.tot_heapover++;
1145 globalParStats.tot_heapover++;
1148 // did the task ask for a large block?
1149 if (cap->r.rHpAlloc > BLOCK_SIZE_W) {
1150 // if so, get one and push it on the front of the nursery.
1154 blocks = (nat)BLOCK_ROUND_UP(cap->r.rHpAlloc * sizeof(W_)) / BLOCK_SIZE;
1156 IF_DEBUG(scheduler,belch("--<< thread %ld (%s) stopped: requesting a large block (size %d)",
1157 t->id, whatNext_strs[t->what_next], blocks));
1159 // don't do this if it would push us over the
1160 // alloc_blocks_lim limit; we'll GC first.
1161 if (alloc_blocks + blocks < alloc_blocks_lim) {
1163 alloc_blocks += blocks;
1164 bd = allocGroup( blocks );
1166 // link the new group into the list
1167 bd->link = cap->r.rCurrentNursery;
1168 bd->u.back = cap->r.rCurrentNursery->u.back;
1169 if (cap->r.rCurrentNursery->u.back != NULL) {
1170 cap->r.rCurrentNursery->u.back->link = bd;
1172 ASSERT(g0s0->blocks == cap->r.rCurrentNursery &&
1173 g0s0->blocks == cap->r.rNursery);
1174 cap->r.rNursery = g0s0->blocks = bd;
1176 cap->r.rCurrentNursery->u.back = bd;
1178 // initialise it as a nursery block. We initialise the
1179 // step, gen_no, and flags field of *every* sub-block in
1180 // this large block, because this is easier than making
1181 // sure that we always find the block head of a large
1182 // block whenever we call Bdescr() (eg. evacuate() and
1183 // isAlive() in the GC would both have to do this, at
1187 for (x = bd; x < bd + blocks; x++) {
1194 // don't forget to update the block count in g0s0.
1195 g0s0->n_blocks += blocks;
1196 // This assert can be a killer if the app is doing lots
1197 // of large block allocations.
1198 ASSERT(countBlocks(g0s0->blocks) == g0s0->n_blocks);
1200 // now update the nursery to point to the new block
1201 cap->r.rCurrentNursery = bd;
1203 // we might be unlucky and have another thread get on the
1204 // run queue before us and steal the large block, but in that
1205 // case the thread will just end up requesting another large
1207 PUSH_ON_RUN_QUEUE(t);
1212 /* make all the running tasks block on a condition variable,
1213 * maybe set context_switch and wait till they all pile in,
1214 * then have them wait on a GC condition variable.
1216 IF_DEBUG(scheduler,belch("--<< thread %ld (%s) stopped: HeapOverflow",
1217 t->id, whatNext_strs[t->what_next]));
1220 ASSERT(!is_on_queue(t,CurrentProc));
1222 /* Currently we emit a DESCHEDULE event before GC in GUM.
1223 ToDo: either add separate event to distinguish SYSTEM time from rest
1224 or just nuke this DESCHEDULE (and the following SCHEDULE) */
1225 if (0 && RtsFlags.ParFlags.ParStats.Full) {
1226 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
1227 GR_DESCHEDULE, t, (StgClosure *)NULL, 0, 0);
1228 emitSchedule = rtsTrue;
1232 ready_to_gc = rtsTrue;
1233 context_switch = 1; /* stop other threads ASAP */
1234 PUSH_ON_RUN_QUEUE(t);
1235 /* actual GC is done at the end of the while loop */
1241 DumpGranEvent(GR_DESCHEDULE, t));
1242 globalGranStats.tot_stackover++;
1245 // DumpGranEvent(GR_DESCHEDULE, t);
1246 globalParStats.tot_stackover++;
1248 IF_DEBUG(scheduler,belch("--<< thread %ld (%s) stopped, StackOverflow",
1249 t->id, whatNext_strs[t->what_next]));
1250 /* just adjust the stack for this thread, then pop it back
1256 /* enlarge the stack */
1257 StgTSO *new_t = threadStackOverflow(t);
1259 /* This TSO has moved, so update any pointers to it from the
1260 * main thread stack. It better not be on any other queues...
1261 * (it shouldn't be).
1263 for (m = main_threads; m != NULL; m = m->link) {
1268 threadPaused(new_t);
1269 PUSH_ON_RUN_QUEUE(new_t);
1273 case ThreadYielding:
1276 DumpGranEvent(GR_DESCHEDULE, t));
1277 globalGranStats.tot_yields++;
1280 // DumpGranEvent(GR_DESCHEDULE, t);
1281 globalParStats.tot_yields++;
1283 /* put the thread back on the run queue. Then, if we're ready to
1284 * GC, check whether this is the last task to stop. If so, wake
1285 * up the GC thread. getThread will block during a GC until the
1289 if (t->what_next != prev_what_next) {
1290 belch("--<< thread %ld (%s) stopped to switch evaluators",
1291 t->id, whatNext_strs[t->what_next]);
1293 belch("--<< thread %ld (%s) stopped, yielding",
1294 t->id, whatNext_strs[t->what_next]);
1299 //belch("&& Doing sanity check on yielding TSO %ld.", t->id);
1301 ASSERT(t->link == END_TSO_QUEUE);
1303 // Shortcut if we're just switching evaluators: don't bother
1304 // doing stack squeezing (which can be expensive), just run the
1306 if (t->what_next != prev_what_next) {
1313 ASSERT(!is_on_queue(t,CurrentProc));
1316 //belch("&& Doing sanity check on all ThreadQueues (and their TSOs).");
1317 checkThreadQsSanity(rtsTrue));
1321 if (RtsFlags.ParFlags.doFairScheduling) {
1322 /* this does round-robin scheduling; good for concurrency */
1323 APPEND_TO_RUN_QUEUE(t);
1325 /* this does unfair scheduling; good for parallelism */
1326 PUSH_ON_RUN_QUEUE(t);
1329 // this does round-robin scheduling; good for concurrency
1330 APPEND_TO_RUN_QUEUE(t);
1334 /* add a ContinueThread event to actually process the thread */
1335 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
1337 t, (StgClosure*)NULL, (rtsSpark*)NULL);
1339 belch("GRAN: eventq and runnableq after adding yielded thread to queue again:");
1348 belch("--<< thread %ld (%p; %s) stopped, blocking on node %p [PE %d] with BQ: ",
1349 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)));
1350 if (t->block_info.closure!=(StgClosure*)NULL) print_bq(t->block_info.closure));
1352 // ??? needed; should emit block before
1354 DumpGranEvent(GR_DESCHEDULE, t));
1355 prune_eventq(t, (StgClosure *)NULL); // prune ContinueThreads for t
1358 ASSERT(procStatus[CurrentProc]==Busy ||
1359 ((procStatus[CurrentProc]==Fetching) &&
1360 (t->block_info.closure!=(StgClosure*)NULL)));
1361 if (run_queue_hds[CurrentProc] == END_TSO_QUEUE &&
1362 !(!RtsFlags.GranFlags.DoAsyncFetch &&
1363 procStatus[CurrentProc]==Fetching))
1364 procStatus[CurrentProc] = Idle;
1368 belch("--<< thread %ld (%p; %s) stopped, blocking on node %p with BQ: ",
1369 t->id, t, whatNext_strs[t->what_next], t->block_info.closure));
1372 if (t->block_info.closure!=(StgClosure*)NULL)
1373 print_bq(t->block_info.closure));
1375 /* Send a fetch (if BlockedOnGA) and dump event to log file */
1378 /* whatever we schedule next, we must log that schedule */
1379 emitSchedule = rtsTrue;
1382 /* don't need to do anything. Either the thread is blocked on
1383 * I/O, in which case we'll have called addToBlockedQueue
1384 * previously, or it's blocked on an MVar or Blackhole, in which
1385 * case it'll be on the relevant queue already.
1388 fprintf(stderr, "--<< thread %d (%s) stopped: ",
1389 t->id, whatNext_strs[t->what_next]);
1390 printThreadBlockage(t);
1391 fprintf(stderr, "\n"));
1393 /* Only for dumping event to log file
1394 ToDo: do I need this in GranSim, too?
1401 case ThreadFinished:
1402 /* Need to check whether this was a main thread, and if so, signal
1403 * the task that started it with the return value. If we have no
1404 * more main threads, we probably need to stop all the tasks until
1407 /* We also end up here if the thread kills itself with an
1408 * uncaught exception, see Exception.hc.
1410 IF_DEBUG(scheduler,belch("--++ thread %d (%s) finished",
1411 t->id, whatNext_strs[t->what_next]));
1413 endThread(t, CurrentProc); // clean-up the thread
1415 /* For now all are advisory -- HWL */
1416 //if(t->priority==AdvisoryPriority) ??
1417 advisory_thread_count--;
1420 if(t->dist.priority==RevalPriority)
1424 if (RtsFlags.ParFlags.ParStats.Full &&
1425 !RtsFlags.ParFlags.ParStats.Suppressed)
1426 DumpEndEvent(CURRENT_PROC, t, rtsFalse /* not mandatory */);
1431 barf("schedule: invalid thread return code %d", (int)ret);
1435 // When we have +RTS -i0 and we're heap profiling, do a census at
1436 // every GC. This lets us get repeatable runs for debugging.
1437 if (performHeapProfile ||
1438 (RtsFlags.ProfFlags.profileInterval==0 &&
1439 RtsFlags.ProfFlags.doHeapProfile && ready_to_gc)) {
1440 GarbageCollect(GetRoots, rtsTrue);
1442 performHeapProfile = rtsFalse;
1443 ready_to_gc = rtsFalse; // we already GC'd
1449 && allFreeCapabilities()
1452 /* everybody back, start the GC.
1453 * Could do it in this thread, or signal a condition var
1454 * to do it in another thread. Either way, we need to
1455 * broadcast on gc_pending_cond afterward.
1457 #if defined(RTS_SUPPORTS_THREADS)
1458 IF_DEBUG(scheduler,sched_belch("doing GC"));
1460 GarbageCollect(GetRoots,rtsFalse);
1461 ready_to_gc = rtsFalse;
1463 broadcastCondition(&gc_pending_cond);
1466 /* add a ContinueThread event to continue execution of current thread */
1467 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
1469 t, (StgClosure*)NULL, (rtsSpark*)NULL);
1471 fprintf(stderr, "GRAN: eventq and runnableq after Garbage collection:\n");
1479 IF_GRAN_DEBUG(unused,
1480 print_eventq(EventHd));
1482 event = get_next_event();
1485 /* ToDo: wait for next message to arrive rather than busy wait */
1488 } /* end of while(1) */
1490 IF_PAR_DEBUG(verbose,
1491 belch("== Leaving schedule() after having received Finish"));
1494 /* ---------------------------------------------------------------------------
1495 * Singleton fork(). Do not copy any running threads.
1496 * ------------------------------------------------------------------------- */
1498 StgInt forkProcess(StgTSO* tso) {
1500 #ifndef mingw32_TARGET_OS
1506 IF_DEBUG(scheduler,sched_belch("forking!"));
1509 if (pid) { /* parent */
1511 /* just return the pid */
1513 } else { /* child */
1514 /* wipe all other threads */
1515 run_queue_hd = run_queue_tl = tso;
1516 tso->link = END_TSO_QUEUE;
1518 /* When clearing out the threads, we need to ensure
1519 that a 'main thread' is left behind; if there isn't,
1520 the Scheduler will shutdown next time it is entered.
1522 ==> we don't kill a thread that's on the main_threads
1523 list (nor the current thread.)
1525 [ Attempts at implementing the more ambitious scheme of
1526 killing the main_threads also, and then adding the
1527 current thread onto the main_threads list if it wasn't
1528 there already, failed -- waitThread() (for one) wasn't
1529 up to it. If it proves to be desirable to also kill
1530 the main threads, then this scheme will have to be
1531 revisited (and fully debugged!)
1536 /* DO NOT TOUCH THE QUEUES directly because most of the code around
1537 us is picky about finding the thread still in its queue when
1538 handling the deleteThread() */
1540 for (t = all_threads; t != END_TSO_QUEUE; t = next) {
1543 /* Don't kill the current thread.. */
1544 if (t->id == tso->id) continue;
1546 /* ..or a main thread */
1547 for (m = main_threads; m != NULL; m = m->link) {
1548 if (m->tso->id == t->id) {
1560 barf("forkProcess#: primop not implemented for mingw32, sorry! (%u)\n", tso->id);
1561 /* pointlessly printing out the TSOs 'id' to avoid CC unused warning. */
1563 #endif /* mingw32 */
1566 /* ---------------------------------------------------------------------------
1567 * deleteAllThreads(): kill all the live threads.
1569 * This is used when we catch a user interrupt (^C), before performing
1570 * any necessary cleanups and running finalizers.
1572 * Locks: sched_mutex held.
1573 * ------------------------------------------------------------------------- */
1575 void deleteAllThreads ( void )
1578 IF_DEBUG(scheduler,sched_belch("deleting all threads"));
1579 for (t = all_threads; t != END_TSO_QUEUE; t = next) {
1580 next = t->global_link;
1583 run_queue_hd = run_queue_tl = END_TSO_QUEUE;
1584 blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
1585 sleeping_queue = END_TSO_QUEUE;
1588 /* startThread and insertThread are now in GranSim.c -- HWL */
1591 //@node Suspend and Resume, Run queue code, Main scheduling loop, Main scheduling code
1592 //@subsection Suspend and Resume
1594 /* ---------------------------------------------------------------------------
1595 * Suspending & resuming Haskell threads.
1597 * When making a "safe" call to C (aka _ccall_GC), the task gives back
1598 * its capability before calling the C function. This allows another
1599 * task to pick up the capability and carry on running Haskell
1600 * threads. It also means that if the C call blocks, it won't lock
1603 * The Haskell thread making the C call is put to sleep for the
1604 * duration of the call, on the susepended_ccalling_threads queue. We
1605 * give out a token to the task, which it can use to resume the thread
1606 * on return from the C function.
1607 * ------------------------------------------------------------------------- */
1610 suspendThread( StgRegTable *reg,
1612 #if !defined(RTS_SUPPORTS_THREADS) && !defined(DEBUG)
1620 /* assume that *reg is a pointer to the StgRegTable part
1623 cap = (Capability *)((void *)reg - sizeof(StgFunTable));
1625 ACQUIRE_LOCK(&sched_mutex);
1628 sched_belch("thread %d did a _ccall_gc (is_concurrent: %d)", cap->r.rCurrentTSO->id,concCall));
1630 // XXX this might not be necessary --SDM
1631 cap->r.rCurrentTSO->what_next = ThreadRunGHC;
1633 threadPaused(cap->r.rCurrentTSO);
1634 cap->r.rCurrentTSO->link = suspended_ccalling_threads;
1635 suspended_ccalling_threads = cap->r.rCurrentTSO;
1637 #if defined(RTS_SUPPORTS_THREADS)
1638 if(cap->r.rCurrentTSO->blocked_exceptions == NULL)
1640 cap->r.rCurrentTSO->why_blocked = BlockedOnCCall;
1641 cap->r.rCurrentTSO->blocked_exceptions = END_TSO_QUEUE;
1645 cap->r.rCurrentTSO->why_blocked = BlockedOnCCall_NoUnblockExc;
1649 /* Use the thread ID as the token; it should be unique */
1650 tok = cap->r.rCurrentTSO->id;
1652 /* Hand back capability */
1653 releaseCapability(cap);
1655 #if defined(RTS_SUPPORTS_THREADS)
1656 /* Preparing to leave the RTS, so ensure there's a native thread/task
1657 waiting to take over.
1659 IF_DEBUG(scheduler, sched_belch("worker thread (%d, osthread %p): leaving RTS", tok, osThreadId()));
1660 //if (concCall) { // implementing "safe" as opposed to "threadsafe" is more difficult
1661 startTask(taskStart);
1665 /* Other threads _might_ be available for execution; signal this */
1667 RELEASE_LOCK(&sched_mutex);
1672 resumeThread( StgInt tok,
1674 #if !defined(RTS_SUPPORTS_THREADS)
1679 StgTSO *tso, **prev;
1682 #if defined(RTS_SUPPORTS_THREADS)
1683 /* Wait for permission to re-enter the RTS with the result. */
1684 ACQUIRE_LOCK(&sched_mutex);
1685 grabReturnCapability(&sched_mutex, &cap);
1687 IF_DEBUG(scheduler, sched_belch("worker thread (%d, osthread %p): re-entering RTS", tok, osThreadId()));
1689 grabCapability(&cap);
1692 /* Remove the thread off of the suspended list */
1693 prev = &suspended_ccalling_threads;
1694 for (tso = suspended_ccalling_threads;
1695 tso != END_TSO_QUEUE;
1696 prev = &tso->link, tso = tso->link) {
1697 if (tso->id == (StgThreadID)tok) {
1702 if (tso == END_TSO_QUEUE) {
1703 barf("resumeThread: thread not found");
1705 tso->link = END_TSO_QUEUE;
1707 #if defined(RTS_SUPPORTS_THREADS)
1708 if(tso->why_blocked == BlockedOnCCall)
1710 awakenBlockedQueueNoLock(tso->blocked_exceptions);
1711 tso->blocked_exceptions = NULL;
1715 /* Reset blocking status */
1716 tso->why_blocked = NotBlocked;
1718 cap->r.rCurrentTSO = tso;
1719 #if defined(RTS_SUPPORTS_THREADS)
1720 RELEASE_LOCK(&sched_mutex);
1726 /* ---------------------------------------------------------------------------
1728 * ------------------------------------------------------------------------ */
1729 static void unblockThread(StgTSO *tso);
1731 /* ---------------------------------------------------------------------------
1732 * Comparing Thread ids.
1734 * This is used from STG land in the implementation of the
1735 * instances of Eq/Ord for ThreadIds.
1736 * ------------------------------------------------------------------------ */
1739 cmp_thread(StgPtr tso1, StgPtr tso2)
1741 StgThreadID id1 = ((StgTSO *)tso1)->id;
1742 StgThreadID id2 = ((StgTSO *)tso2)->id;
1744 if (id1 < id2) return (-1);
1745 if (id1 > id2) return 1;
1749 /* ---------------------------------------------------------------------------
1750 * Fetching the ThreadID from an StgTSO.
1752 * This is used in the implementation of Show for ThreadIds.
1753 * ------------------------------------------------------------------------ */
1755 rts_getThreadId(StgPtr tso)
1757 return ((StgTSO *)tso)->id;
1762 labelThread(StgPtr tso, char *label)
1767 /* Caveat: Once set, you can only set the thread name to "" */
1768 len = strlen(label)+1;
1771 fprintf(stderr,"insufficient memory for labelThread!\n");
1773 strncpy(buf,label,len);
1774 /* Update will free the old memory for us */
1775 updateThreadLabel((StgWord)tso,buf);
1779 /* ---------------------------------------------------------------------------
1780 Create a new thread.
1782 The new thread starts with the given stack size. Before the
1783 scheduler can run, however, this thread needs to have a closure
1784 (and possibly some arguments) pushed on its stack. See
1785 pushClosure() in Schedule.h.
1787 createGenThread() and createIOThread() (in SchedAPI.h) are
1788 convenient packaged versions of this function.
1790 currently pri (priority) is only used in a GRAN setup -- HWL
1791 ------------------------------------------------------------------------ */
1792 //@cindex createThread
1794 /* currently pri (priority) is only used in a GRAN setup -- HWL */
1796 createThread(nat size, StgInt pri)
1799 createThread(nat size)
1806 /* First check whether we should create a thread at all */
1808 /* check that no more than RtsFlags.ParFlags.maxThreads threads are created */
1809 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads) {
1811 belch("{createThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
1812 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
1813 return END_TSO_QUEUE;
1819 ASSERT(!RtsFlags.GranFlags.Light || CurrentProc==0);
1822 // ToDo: check whether size = stack_size - TSO_STRUCT_SIZEW
1824 /* catch ridiculously small stack sizes */
1825 if (size < MIN_STACK_WORDS + TSO_STRUCT_SIZEW) {
1826 size = MIN_STACK_WORDS + TSO_STRUCT_SIZEW;
1829 stack_size = size - TSO_STRUCT_SIZEW;
1831 tso = (StgTSO *)allocate(size);
1832 TICK_ALLOC_TSO(stack_size, 0);
1834 SET_HDR(tso, &stg_TSO_info, CCS_SYSTEM);
1836 SET_GRAN_HDR(tso, ThisPE);
1839 // Always start with the compiled code evaluator
1840 tso->what_next = ThreadRunGHC;
1842 /* tso->id needs to be unique. For now we use a heavyweight mutex to
1843 * protect the increment operation on next_thread_id.
1844 * In future, we could use an atomic increment instead.
1846 ACQUIRE_LOCK(&thread_id_mutex);
1847 tso->id = next_thread_id++;
1848 RELEASE_LOCK(&thread_id_mutex);
1850 tso->why_blocked = NotBlocked;
1851 tso->blocked_exceptions = NULL;
1853 tso->stack_size = stack_size;
1854 tso->max_stack_size = round_to_mblocks(RtsFlags.GcFlags.maxStkSize)
1856 tso->sp = (P_)&(tso->stack) + stack_size;
1859 tso->prof.CCCS = CCS_MAIN;
1862 /* put a stop frame on the stack */
1863 tso->sp -= sizeofW(StgStopFrame);
1864 SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_SYSTEM);
1867 tso->link = END_TSO_QUEUE;
1868 /* uses more flexible routine in GranSim */
1869 insertThread(tso, CurrentProc);
1871 /* In a non-GranSim setup the pushing of a TSO onto the runq is separated
1877 if (RtsFlags.GranFlags.GranSimStats.Full)
1878 DumpGranEvent(GR_START,tso);
1880 if (RtsFlags.ParFlags.ParStats.Full)
1881 DumpGranEvent(GR_STARTQ,tso);
1882 /* HACk to avoid SCHEDULE
1886 /* Link the new thread on the global thread list.
1888 tso->global_link = all_threads;
1892 tso->dist.priority = MandatoryPriority; //by default that is...
1896 tso->gran.pri = pri;
1898 tso->gran.magic = TSO_MAGIC; // debugging only
1900 tso->gran.sparkname = 0;
1901 tso->gran.startedat = CURRENT_TIME;
1902 tso->gran.exported = 0;
1903 tso->gran.basicblocks = 0;
1904 tso->gran.allocs = 0;
1905 tso->gran.exectime = 0;
1906 tso->gran.fetchtime = 0;
1907 tso->gran.fetchcount = 0;
1908 tso->gran.blocktime = 0;
1909 tso->gran.blockcount = 0;
1910 tso->gran.blockedat = 0;
1911 tso->gran.globalsparks = 0;
1912 tso->gran.localsparks = 0;
1913 if (RtsFlags.GranFlags.Light)
1914 tso->gran.clock = Now; /* local clock */
1916 tso->gran.clock = 0;
1918 IF_DEBUG(gran,printTSO(tso));
1921 tso->par.magic = TSO_MAGIC; // debugging only
1923 tso->par.sparkname = 0;
1924 tso->par.startedat = CURRENT_TIME;
1925 tso->par.exported = 0;
1926 tso->par.basicblocks = 0;
1927 tso->par.allocs = 0;
1928 tso->par.exectime = 0;
1929 tso->par.fetchtime = 0;
1930 tso->par.fetchcount = 0;
1931 tso->par.blocktime = 0;
1932 tso->par.blockcount = 0;
1933 tso->par.blockedat = 0;
1934 tso->par.globalsparks = 0;
1935 tso->par.localsparks = 0;
1939 globalGranStats.tot_threads_created++;
1940 globalGranStats.threads_created_on_PE[CurrentProc]++;
1941 globalGranStats.tot_sq_len += spark_queue_len(CurrentProc);
1942 globalGranStats.tot_sq_probes++;
1944 // collect parallel global statistics (currently done together with GC stats)
1945 if (RtsFlags.ParFlags.ParStats.Global &&
1946 RtsFlags.GcFlags.giveStats > NO_GC_STATS) {
1947 //fprintf(stderr, "Creating thread %d @ %11.2f\n", tso->id, usertime());
1948 globalParStats.tot_threads_created++;
1954 belch("==__ schedule: Created TSO %d (%p);",
1955 CurrentProc, tso, tso->id));
1957 IF_PAR_DEBUG(verbose,
1958 belch("==__ schedule: Created TSO %d (%p); %d threads active",
1959 tso->id, tso, advisory_thread_count));
1961 IF_DEBUG(scheduler,sched_belch("created thread %ld, stack size = %lx words",
1962 tso->id, tso->stack_size));
1969 all parallel thread creation calls should fall through the following routine.
1972 createSparkThread(rtsSpark spark)
1974 ASSERT(spark != (rtsSpark)NULL);
1975 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads)
1977 barf("{createSparkThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
1978 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
1979 return END_TSO_QUEUE;
1983 tso = createThread(RtsFlags.GcFlags.initialStkSize);
1984 if (tso==END_TSO_QUEUE)
1985 barf("createSparkThread: Cannot create TSO");
1987 tso->priority = AdvisoryPriority;
1989 pushClosure(tso,spark);
1990 PUSH_ON_RUN_QUEUE(tso);
1991 advisory_thread_count++;
1998 Turn a spark into a thread.
1999 ToDo: fix for SMP (needs to acquire SCHED_MUTEX!)
2002 //@cindex activateSpark
2004 activateSpark (rtsSpark spark)
2008 tso = createSparkThread(spark);
2009 if (RtsFlags.ParFlags.ParStats.Full) {
2010 //ASSERT(run_queue_hd == END_TSO_QUEUE); // I think ...
2011 IF_PAR_DEBUG(verbose,
2012 belch("==^^ activateSpark: turning spark of closure %p (%s) into a thread",
2013 (StgClosure *)spark, info_type((StgClosure *)spark)));
2015 // ToDo: fwd info on local/global spark to thread -- HWL
2016 // tso->gran.exported = spark->exported;
2017 // tso->gran.locked = !spark->global;
2018 // tso->gran.sparkname = spark->name;
2024 static SchedulerStatus waitThread_(/*out*/StgMainThread* m
2025 #if defined(THREADED_RTS)
2026 , rtsBool blockWaiting
2031 /* ---------------------------------------------------------------------------
2034 * scheduleThread puts a thread on the head of the runnable queue.
2035 * This will usually be done immediately after a thread is created.
2036 * The caller of scheduleThread must create the thread using e.g.
2037 * createThread and push an appropriate closure
2038 * on this thread's stack before the scheduler is invoked.
2039 * ------------------------------------------------------------------------ */
2041 static void scheduleThread_ (StgTSO* tso);
2044 scheduleThread_(StgTSO *tso)
2046 // Precondition: sched_mutex must be held.
2048 /* Put the new thread on the head of the runnable queue. The caller
2049 * better push an appropriate closure on this thread's stack
2050 * beforehand. In the SMP case, the thread may start running as
2051 * soon as we release the scheduler lock below.
2053 PUSH_ON_RUN_QUEUE(tso);
2057 IF_DEBUG(scheduler,printTSO(tso));
2061 void scheduleThread(StgTSO* tso)
2063 ACQUIRE_LOCK(&sched_mutex);
2064 scheduleThread_(tso);
2065 RELEASE_LOCK(&sched_mutex);
2069 scheduleWaitThread(StgTSO* tso, /*[out]*/HaskellObj* ret)
2070 { // Precondition: sched_mutex must be held
2073 m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
2077 #if defined(RTS_SUPPORTS_THREADS)
2078 initCondition(&m->wakeup);
2081 /* Put the thread on the main-threads list prior to scheduling the TSO.
2082 Failure to do so introduces a race condition in the MT case (as
2083 identified by Wolfgang Thaller), whereby the new task/OS thread
2084 created by scheduleThread_() would complete prior to the thread
2085 that spawned it managed to put 'itself' on the main-threads list.
2086 The upshot of it all being that the worker thread wouldn't get to
2087 signal the completion of the its work item for the main thread to
2088 see (==> it got stuck waiting.) -- sof 6/02.
2090 IF_DEBUG(scheduler, sched_belch("waiting for thread (%d)\n", tso->id));
2092 m->link = main_threads;
2095 scheduleThread_(tso);
2096 #if defined(THREADED_RTS)
2097 return waitThread_(m, rtsTrue);
2099 return waitThread_(m);
2103 /* ---------------------------------------------------------------------------
2106 * Initialise the scheduler. This resets all the queues - if the
2107 * queues contained any threads, they'll be garbage collected at the
2110 * ------------------------------------------------------------------------ */
2114 term_handler(int sig STG_UNUSED)
2117 ACQUIRE_LOCK(&term_mutex);
2119 RELEASE_LOCK(&term_mutex);
2130 for (i=0; i<=MAX_PROC; i++) {
2131 run_queue_hds[i] = END_TSO_QUEUE;
2132 run_queue_tls[i] = END_TSO_QUEUE;
2133 blocked_queue_hds[i] = END_TSO_QUEUE;
2134 blocked_queue_tls[i] = END_TSO_QUEUE;
2135 ccalling_threadss[i] = END_TSO_QUEUE;
2136 sleeping_queue = END_TSO_QUEUE;
2139 run_queue_hd = END_TSO_QUEUE;
2140 run_queue_tl = END_TSO_QUEUE;
2141 blocked_queue_hd = END_TSO_QUEUE;
2142 blocked_queue_tl = END_TSO_QUEUE;
2143 sleeping_queue = END_TSO_QUEUE;
2146 suspended_ccalling_threads = END_TSO_QUEUE;
2148 main_threads = NULL;
2149 all_threads = END_TSO_QUEUE;
2154 RtsFlags.ConcFlags.ctxtSwitchTicks =
2155 RtsFlags.ConcFlags.ctxtSwitchTime / TICK_MILLISECS;
2157 #if defined(RTS_SUPPORTS_THREADS)
2158 /* Initialise the mutex and condition variables used by
2160 initMutex(&sched_mutex);
2161 initMutex(&term_mutex);
2162 initMutex(&thread_id_mutex);
2164 initCondition(&thread_ready_cond);
2168 initCondition(&gc_pending_cond);
2171 #if defined(RTS_SUPPORTS_THREADS)
2172 ACQUIRE_LOCK(&sched_mutex);
2175 /* Install the SIGHUP handler */
2178 struct sigaction action,oact;
2180 action.sa_handler = term_handler;
2181 sigemptyset(&action.sa_mask);
2182 action.sa_flags = 0;
2183 if (sigaction(SIGTERM, &action, &oact) != 0) {
2184 barf("can't install TERM handler");
2189 /* A capability holds the state a native thread needs in
2190 * order to execute STG code. At least one capability is
2191 * floating around (only SMP builds have more than one).
2195 #if defined(RTS_SUPPORTS_THREADS)
2196 /* start our haskell execution tasks */
2198 startTaskManager(RtsFlags.ParFlags.nNodes, taskStart);
2200 startTaskManager(0,taskStart);
2204 #if /* defined(SMP) ||*/ defined(PAR)
2208 #if defined(RTS_SUPPORTS_THREADS)
2209 RELEASE_LOCK(&sched_mutex);
2215 exitScheduler( void )
2217 #if defined(RTS_SUPPORTS_THREADS)
2220 shutting_down_scheduler = rtsTrue;
2223 /* -----------------------------------------------------------------------------
2224 Managing the per-task allocation areas.
2226 Each capability comes with an allocation area. These are
2227 fixed-length block lists into which allocation can be done.
2229 ToDo: no support for two-space collection at the moment???
2230 -------------------------------------------------------------------------- */
2232 /* -----------------------------------------------------------------------------
2233 * waitThread is the external interface for running a new computation
2234 * and waiting for the result.
2236 * In the non-SMP case, we create a new main thread, push it on the
2237 * main-thread stack, and invoke the scheduler to run it. The
2238 * scheduler will return when the top main thread on the stack has
2239 * completed or died, and fill in the necessary fields of the
2240 * main_thread structure.
2242 * In the SMP case, we create a main thread as before, but we then
2243 * create a new condition variable and sleep on it. When our new
2244 * main thread has completed, we'll be woken up and the status/result
2245 * will be in the main_thread struct.
2246 * -------------------------------------------------------------------------- */
2249 howManyThreadsAvail ( void )
2253 for (q = run_queue_hd; q != END_TSO_QUEUE; q = q->link)
2255 for (q = blocked_queue_hd; q != END_TSO_QUEUE; q = q->link)
2257 for (q = sleeping_queue; q != END_TSO_QUEUE; q = q->link)
2263 finishAllThreads ( void )
2266 while (run_queue_hd != END_TSO_QUEUE) {
2267 waitThread ( run_queue_hd, NULL);
2269 while (blocked_queue_hd != END_TSO_QUEUE) {
2270 waitThread ( blocked_queue_hd, NULL);
2272 while (sleeping_queue != END_TSO_QUEUE) {
2273 waitThread ( blocked_queue_hd, NULL);
2276 (blocked_queue_hd != END_TSO_QUEUE ||
2277 run_queue_hd != END_TSO_QUEUE ||
2278 sleeping_queue != END_TSO_QUEUE);
2282 waitThread(StgTSO *tso, /*out*/StgClosure **ret)
2285 SchedulerStatus stat;
2287 m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
2291 #if defined(RTS_SUPPORTS_THREADS)
2292 initCondition(&m->wakeup);
2295 /* see scheduleWaitThread() comment */
2296 ACQUIRE_LOCK(&sched_mutex);
2297 m->link = main_threads;
2300 IF_DEBUG(scheduler, sched_belch("waiting for thread %d", tso->id));
2301 #if defined(THREADED_RTS)
2302 stat = waitThread_(m, rtsFalse);
2304 stat = waitThread_(m);
2306 RELEASE_LOCK(&sched_mutex);
2312 waitThread_(StgMainThread* m
2313 #if defined(THREADED_RTS)
2314 , rtsBool blockWaiting
2318 SchedulerStatus stat;
2320 // Precondition: sched_mutex must be held.
2321 IF_DEBUG(scheduler, sched_belch("== scheduler: new main thread (%d)\n", m->tso->id));
2323 #if defined(RTS_SUPPORTS_THREADS)
2325 # if defined(THREADED_RTS)
2326 if (!blockWaiting) {
2327 /* In the threaded case, the OS thread that called main()
2328 * gets to enter the RTS directly without going via another
2331 main_main_thread = m;
2332 RELEASE_LOCK(&sched_mutex);
2334 ACQUIRE_LOCK(&sched_mutex);
2335 main_main_thread = NULL;
2336 ASSERT(m->stat != NoStatus);
2341 waitCondition(&m->wakeup, &sched_mutex);
2342 } while (m->stat == NoStatus);
2345 /* GranSim specific init */
2346 CurrentTSO = m->tso; // the TSO to run
2347 procStatus[MainProc] = Busy; // status of main PE
2348 CurrentProc = MainProc; // PE to run it on
2350 RELEASE_LOCK(&sched_mutex);
2353 RELEASE_LOCK(&sched_mutex);
2355 ASSERT(m->stat != NoStatus);
2360 #if defined(RTS_SUPPORTS_THREADS)
2361 closeCondition(&m->wakeup);
2364 IF_DEBUG(scheduler, fprintf(stderr, "== scheduler: main thread (%d) finished\n",
2368 // Postcondition: sched_mutex still held
2372 //@node Run queue code, Garbage Collextion Routines, Suspend and Resume, Main scheduling code
2373 //@subsection Run queue code
2377 NB: In GranSim we have many run queues; run_queue_hd is actually a macro
2378 unfolding to run_queue_hds[CurrentProc], thus CurrentProc is an
2379 implicit global variable that has to be correct when calling these
2383 /* Put the new thread on the head of the runnable queue.
2384 * The caller of createThread better push an appropriate closure
2385 * on this thread's stack before the scheduler is invoked.
2387 static /* inline */ void
2388 add_to_run_queue(tso)
2391 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
2392 tso->link = run_queue_hd;
2394 if (run_queue_tl == END_TSO_QUEUE) {
2399 /* Put the new thread at the end of the runnable queue. */
2400 static /* inline */ void
2401 push_on_run_queue(tso)
2404 ASSERT(get_itbl((StgClosure *)tso)->type == TSO);
2405 ASSERT(run_queue_hd!=NULL && run_queue_tl!=NULL);
2406 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
2407 if (run_queue_hd == END_TSO_QUEUE) {
2410 run_queue_tl->link = tso;
2416 Should be inlined because it's used very often in schedule. The tso
2417 argument is actually only needed in GranSim, where we want to have the
2418 possibility to schedule *any* TSO on the run queue, irrespective of the
2419 actual ordering. Therefore, if tso is not the nil TSO then we traverse
2420 the run queue and dequeue the tso, adjusting the links in the queue.
2422 //@cindex take_off_run_queue
2423 static /* inline */ StgTSO*
2424 take_off_run_queue(StgTSO *tso) {
2428 qetlaHbogh Qu' ngaSbogh ghomDaQ {tso} yIteq!
2430 if tso is specified, unlink that tso from the run_queue (doesn't have
2431 to be at the beginning of the queue); GranSim only
2433 if (tso!=END_TSO_QUEUE) {
2434 /* find tso in queue */
2435 for (t=run_queue_hd, prev=END_TSO_QUEUE;
2436 t!=END_TSO_QUEUE && t!=tso;
2440 /* now actually dequeue the tso */
2441 if (prev!=END_TSO_QUEUE) {
2442 ASSERT(run_queue_hd!=t);
2443 prev->link = t->link;
2445 /* t is at beginning of thread queue */
2446 ASSERT(run_queue_hd==t);
2447 run_queue_hd = t->link;
2449 /* t is at end of thread queue */
2450 if (t->link==END_TSO_QUEUE) {
2451 ASSERT(t==run_queue_tl);
2452 run_queue_tl = prev;
2454 ASSERT(run_queue_tl!=t);
2456 t->link = END_TSO_QUEUE;
2458 /* take tso from the beginning of the queue; std concurrent code */
2460 if (t != END_TSO_QUEUE) {
2461 run_queue_hd = t->link;
2462 t->link = END_TSO_QUEUE;
2463 if (run_queue_hd == END_TSO_QUEUE) {
2464 run_queue_tl = END_TSO_QUEUE;
2473 //@node Garbage Collextion Routines, Blocking Queue Routines, Run queue code, Main scheduling code
2474 //@subsection Garbage Collextion Routines
2476 /* ---------------------------------------------------------------------------
2477 Where are the roots that we know about?
2479 - all the threads on the runnable queue
2480 - all the threads on the blocked queue
2481 - all the threads on the sleeping queue
2482 - all the thread currently executing a _ccall_GC
2483 - all the "main threads"
2485 ------------------------------------------------------------------------ */
2487 /* This has to be protected either by the scheduler monitor, or by the
2488 garbage collection monitor (probably the latter).
2493 GetRoots(evac_fn evac)
2498 for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
2499 if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
2500 evac((StgClosure **)&run_queue_hds[i]);
2501 if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
2502 evac((StgClosure **)&run_queue_tls[i]);
2504 if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
2505 evac((StgClosure **)&blocked_queue_hds[i]);
2506 if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
2507 evac((StgClosure **)&blocked_queue_tls[i]);
2508 if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
2509 evac((StgClosure **)&ccalling_threads[i]);
2516 if (run_queue_hd != END_TSO_QUEUE) {
2517 ASSERT(run_queue_tl != END_TSO_QUEUE);
2518 evac((StgClosure **)&run_queue_hd);
2519 evac((StgClosure **)&run_queue_tl);
2522 if (blocked_queue_hd != END_TSO_QUEUE) {
2523 ASSERT(blocked_queue_tl != END_TSO_QUEUE);
2524 evac((StgClosure **)&blocked_queue_hd);
2525 evac((StgClosure **)&blocked_queue_tl);
2528 if (sleeping_queue != END_TSO_QUEUE) {
2529 evac((StgClosure **)&sleeping_queue);
2533 if (suspended_ccalling_threads != END_TSO_QUEUE) {
2534 evac((StgClosure **)&suspended_ccalling_threads);
2537 #if defined(PAR) || defined(GRAN)
2538 markSparkQueue(evac);
2541 #ifndef mingw32_TARGET_OS
2542 // mark the signal handlers (signals should be already blocked)
2543 markSignalHandlers(evac);
2546 // main threads which have completed need to be retained until they
2547 // are dealt with in the main scheduler loop. They won't be
2548 // retained any other way: the GC will drop them from the
2549 // all_threads list, so we have to be careful to treat them as roots
2553 for (m = main_threads; m != NULL; m = m->link) {
2554 switch (m->tso->what_next) {
2555 case ThreadComplete:
2557 evac((StgClosure **)&m->tso);
2566 /* -----------------------------------------------------------------------------
2569 This is the interface to the garbage collector from Haskell land.
2570 We provide this so that external C code can allocate and garbage
2571 collect when called from Haskell via _ccall_GC.
2573 It might be useful to provide an interface whereby the programmer
2574 can specify more roots (ToDo).
2576 This needs to be protected by the GC condition variable above. KH.
2577 -------------------------------------------------------------------------- */
2579 static void (*extra_roots)(evac_fn);
2584 /* Obligated to hold this lock upon entry */
2585 ACQUIRE_LOCK(&sched_mutex);
2586 GarbageCollect(GetRoots,rtsFalse);
2587 RELEASE_LOCK(&sched_mutex);
2591 performMajorGC(void)
2593 ACQUIRE_LOCK(&sched_mutex);
2594 GarbageCollect(GetRoots,rtsTrue);
2595 RELEASE_LOCK(&sched_mutex);
2599 AllRoots(evac_fn evac)
2601 GetRoots(evac); // the scheduler's roots
2602 extra_roots(evac); // the user's roots
2606 performGCWithRoots(void (*get_roots)(evac_fn))
2608 ACQUIRE_LOCK(&sched_mutex);
2609 extra_roots = get_roots;
2610 GarbageCollect(AllRoots,rtsFalse);
2611 RELEASE_LOCK(&sched_mutex);
2614 /* -----------------------------------------------------------------------------
2617 If the thread has reached its maximum stack size, then raise the
2618 StackOverflow exception in the offending thread. Otherwise
2619 relocate the TSO into a larger chunk of memory and adjust its stack
2621 -------------------------------------------------------------------------- */
2624 threadStackOverflow(StgTSO *tso)
2626 nat new_stack_size, new_tso_size, diff, stack_words;
2630 IF_DEBUG(sanity,checkTSO(tso));
2631 if (tso->stack_size >= tso->max_stack_size) {
2634 belch("@@ threadStackOverflow of TSO %d (%p): stack too large (now %ld; max is %ld",
2635 tso->id, tso, tso->stack_size, tso->max_stack_size);
2636 /* If we're debugging, just print out the top of the stack */
2637 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2640 /* Send this thread the StackOverflow exception */
2641 raiseAsync(tso, (StgClosure *)stackOverflow_closure);
2645 /* Try to double the current stack size. If that takes us over the
2646 * maximum stack size for this thread, then use the maximum instead.
2647 * Finally round up so the TSO ends up as a whole number of blocks.
2649 new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
2650 new_tso_size = (nat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
2651 TSO_STRUCT_SIZE)/sizeof(W_);
2652 new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
2653 new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
2655 IF_DEBUG(scheduler, fprintf(stderr,"== scheduler: increasing stack size from %d words to %d.\n", tso->stack_size, new_stack_size));
2657 dest = (StgTSO *)allocate(new_tso_size);
2658 TICK_ALLOC_TSO(new_stack_size,0);
2660 /* copy the TSO block and the old stack into the new area */
2661 memcpy(dest,tso,TSO_STRUCT_SIZE);
2662 stack_words = tso->stack + tso->stack_size - tso->sp;
2663 new_sp = (P_)dest + new_tso_size - stack_words;
2664 memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
2666 /* relocate the stack pointers... */
2667 diff = (P_)new_sp - (P_)tso->sp; /* In *words* */
2669 dest->stack_size = new_stack_size;
2671 /* Mark the old TSO as relocated. We have to check for relocated
2672 * TSOs in the garbage collector and any primops that deal with TSOs.
2674 * It's important to set the sp value to just beyond the end
2675 * of the stack, so we don't attempt to scavenge any part of the
2678 tso->what_next = ThreadRelocated;
2680 tso->sp = (P_)&(tso->stack[tso->stack_size]);
2681 tso->why_blocked = NotBlocked;
2682 dest->mut_link = NULL;
2684 IF_PAR_DEBUG(verbose,
2685 belch("@@ threadStackOverflow of TSO %d (now at %p): stack size increased to %ld",
2686 tso->id, tso, tso->stack_size);
2687 /* If we're debugging, just print out the top of the stack */
2688 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2691 IF_DEBUG(sanity,checkTSO(tso));
2693 IF_DEBUG(scheduler,printTSO(dest));
2699 //@node Blocking Queue Routines, Exception Handling Routines, Garbage Collextion Routines, Main scheduling code
2700 //@subsection Blocking Queue Routines
2702 /* ---------------------------------------------------------------------------
2703 Wake up a queue that was blocked on some resource.
2704 ------------------------------------------------------------------------ */
2708 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2713 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2715 /* write RESUME events to log file and
2716 update blocked and fetch time (depending on type of the orig closure) */
2717 if (RtsFlags.ParFlags.ParStats.Full) {
2718 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
2719 GR_RESUMEQ, ((StgTSO *)bqe), ((StgTSO *)bqe)->block_info.closure,
2720 0, 0 /* spark_queue_len(ADVISORY_POOL) */);
2721 if (EMPTY_RUN_QUEUE())
2722 emitSchedule = rtsTrue;
2724 switch (get_itbl(node)->type) {
2726 ((StgTSO *)bqe)->par.fetchtime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2731 ((StgTSO *)bqe)->par.blocktime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2738 barf("{unblockOneLocked}Daq Qagh: unexpected closure in blocking queue");
2745 static StgBlockingQueueElement *
2746 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2749 PEs node_loc, tso_loc;
2751 node_loc = where_is(node); // should be lifted out of loop
2752 tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2753 tso_loc = where_is((StgClosure *)tso);
2754 if (IS_LOCAL_TO(PROCS(node),tso_loc)) { // TSO is local
2755 /* !fake_fetch => TSO is on CurrentProc is same as IS_LOCAL_TO */
2756 ASSERT(CurrentProc!=node_loc || tso_loc==CurrentProc);
2757 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.lunblocktime;
2758 // insertThread(tso, node_loc);
2759 new_event(tso_loc, tso_loc, CurrentTime[CurrentProc],
2761 tso, node, (rtsSpark*)NULL);
2762 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2765 } else { // TSO is remote (actually should be FMBQ)
2766 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.mpacktime +
2767 RtsFlags.GranFlags.Costs.gunblocktime +
2768 RtsFlags.GranFlags.Costs.latency;
2769 new_event(tso_loc, CurrentProc, CurrentTime[CurrentProc],
2771 tso, node, (rtsSpark*)NULL);
2772 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2775 /* the thread-queue-overhead is accounted for in either Resume or UnblockThread */
2777 fprintf(stderr," %s TSO %d (%p) [PE %d] (block_info.closure=%p) (next=%p) ,",
2778 (node_loc==tso_loc ? "Local" : "Global"),
2779 tso->id, tso, CurrentProc, tso->block_info.closure, tso->link));
2780 tso->block_info.closure = NULL;
2781 IF_DEBUG(scheduler,belch("-- Waking up thread %ld (%p)",
2785 static StgBlockingQueueElement *
2786 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2788 StgBlockingQueueElement *next;
2790 switch (get_itbl(bqe)->type) {
2792 ASSERT(((StgTSO *)bqe)->why_blocked != NotBlocked);
2793 /* if it's a TSO just push it onto the run_queue */
2795 // ((StgTSO *)bqe)->link = END_TSO_QUEUE; // debugging?
2796 PUSH_ON_RUN_QUEUE((StgTSO *)bqe);
2798 unblockCount(bqe, node);
2799 /* reset blocking status after dumping event */
2800 ((StgTSO *)bqe)->why_blocked = NotBlocked;
2804 /* if it's a BLOCKED_FETCH put it on the PendingFetches list */
2806 bqe->link = (StgBlockingQueueElement *)PendingFetches;
2807 PendingFetches = (StgBlockedFetch *)bqe;
2811 /* can ignore this case in a non-debugging setup;
2812 see comments on RBHSave closures above */
2814 /* check that the closure is an RBHSave closure */
2815 ASSERT(get_itbl((StgClosure *)bqe) == &stg_RBH_Save_0_info ||
2816 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_1_info ||
2817 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_2_info);
2821 barf("{unblockOneLocked}Daq Qagh: Unexpected IP (%#lx; %s) in blocking queue at %#lx\n",
2822 get_itbl((StgClosure *)bqe), info_type((StgClosure *)bqe),
2826 IF_PAR_DEBUG(bq, fprintf(stderr, ", %p (%s)", bqe, info_type((StgClosure*)bqe)));
2830 #else /* !GRAN && !PAR */
2832 unblockOneLocked(StgTSO *tso)
2836 ASSERT(get_itbl(tso)->type == TSO);
2837 ASSERT(tso->why_blocked != NotBlocked);
2838 tso->why_blocked = NotBlocked;
2840 PUSH_ON_RUN_QUEUE(tso);
2842 IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
2847 #if defined(GRAN) || defined(PAR)
2848 inline StgBlockingQueueElement *
2849 unblockOne(StgBlockingQueueElement *bqe, StgClosure *node)
2851 ACQUIRE_LOCK(&sched_mutex);
2852 bqe = unblockOneLocked(bqe, node);
2853 RELEASE_LOCK(&sched_mutex);
2858 unblockOne(StgTSO *tso)
2860 ACQUIRE_LOCK(&sched_mutex);
2861 tso = unblockOneLocked(tso);
2862 RELEASE_LOCK(&sched_mutex);
2869 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2871 StgBlockingQueueElement *bqe;
2876 belch("##-_ AwBQ for node %p on PE %d @ %ld by TSO %d (%p): ", \
2877 node, CurrentProc, CurrentTime[CurrentProc],
2878 CurrentTSO->id, CurrentTSO));
2880 node_loc = where_is(node);
2882 ASSERT(q == END_BQ_QUEUE ||
2883 get_itbl(q)->type == TSO || // q is either a TSO or an RBHSave
2884 get_itbl(q)->type == CONSTR); // closure (type constructor)
2885 ASSERT(is_unique(node));
2887 /* FAKE FETCH: magically copy the node to the tso's proc;
2888 no Fetch necessary because in reality the node should not have been
2889 moved to the other PE in the first place
2891 if (CurrentProc!=node_loc) {
2893 belch("## node %p is on PE %d but CurrentProc is %d (TSO %d); assuming fake fetch and adjusting bitmask (old: %#x)",
2894 node, node_loc, CurrentProc, CurrentTSO->id,
2895 // CurrentTSO, where_is(CurrentTSO),
2896 node->header.gran.procs));
2897 node->header.gran.procs = (node->header.gran.procs) | PE_NUMBER(CurrentProc);
2899 belch("## new bitmask of node %p is %#x",
2900 node, node->header.gran.procs));
2901 if (RtsFlags.GranFlags.GranSimStats.Global) {
2902 globalGranStats.tot_fake_fetches++;
2907 // ToDo: check: ASSERT(CurrentProc==node_loc);
2908 while (get_itbl(bqe)->type==TSO) { // q != END_TSO_QUEUE) {
2911 bqe points to the current element in the queue
2912 next points to the next element in the queue
2914 //tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2915 //tso_loc = where_is(tso);
2917 bqe = unblockOneLocked(bqe, node);
2920 /* if this is the BQ of an RBH, we have to put back the info ripped out of
2921 the closure to make room for the anchor of the BQ */
2922 if (bqe!=END_BQ_QUEUE) {
2923 ASSERT(get_itbl(node)->type == RBH && get_itbl(bqe)->type == CONSTR);
2925 ASSERT((info_ptr==&RBH_Save_0_info) ||
2926 (info_ptr==&RBH_Save_1_info) ||
2927 (info_ptr==&RBH_Save_2_info));
2929 /* cf. convertToRBH in RBH.c for writing the RBHSave closure */
2930 ((StgRBH *)node)->blocking_queue = (StgBlockingQueueElement *)((StgRBHSave *)bqe)->payload[0];
2931 ((StgRBH *)node)->mut_link = (StgMutClosure *)((StgRBHSave *)bqe)->payload[1];
2934 belch("## Filled in RBH_Save for %p (%s) at end of AwBQ",
2935 node, info_type(node)));
2938 /* statistics gathering */
2939 if (RtsFlags.GranFlags.GranSimStats.Global) {
2940 // globalGranStats.tot_bq_processing_time += bq_processing_time;
2941 globalGranStats.tot_bq_len += len; // total length of all bqs awakened
2942 // globalGranStats.tot_bq_len_local += len_local; // same for local TSOs only
2943 globalGranStats.tot_awbq++; // total no. of bqs awakened
2946 fprintf(stderr,"## BQ Stats of %p: [%d entries] %s\n",
2947 node, len, (bqe!=END_BQ_QUEUE) ? "RBH" : ""));
2951 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2953 StgBlockingQueueElement *bqe;
2955 ACQUIRE_LOCK(&sched_mutex);
2957 IF_PAR_DEBUG(verbose,
2958 belch("##-_ AwBQ for node %p on [%x]: ",
2962 if(get_itbl(q)->type == CONSTR || q==END_BQ_QUEUE) {
2963 IF_PAR_DEBUG(verbose, belch("## ... nothing to unblock so lets just return. RFP (BUG?)"));
2968 ASSERT(q == END_BQ_QUEUE ||
2969 get_itbl(q)->type == TSO ||
2970 get_itbl(q)->type == BLOCKED_FETCH ||
2971 get_itbl(q)->type == CONSTR);
2974 while (get_itbl(bqe)->type==TSO ||
2975 get_itbl(bqe)->type==BLOCKED_FETCH) {
2976 bqe = unblockOneLocked(bqe, node);
2978 RELEASE_LOCK(&sched_mutex);
2981 #else /* !GRAN && !PAR */
2983 #ifdef RTS_SUPPORTS_THREADS
2985 awakenBlockedQueueNoLock(StgTSO *tso)
2987 while (tso != END_TSO_QUEUE) {
2988 tso = unblockOneLocked(tso);
2994 awakenBlockedQueue(StgTSO *tso)
2996 ACQUIRE_LOCK(&sched_mutex);
2997 while (tso != END_TSO_QUEUE) {
2998 tso = unblockOneLocked(tso);
3000 RELEASE_LOCK(&sched_mutex);
3004 //@node Exception Handling Routines, Debugging Routines, Blocking Queue Routines, Main scheduling code
3005 //@subsection Exception Handling Routines
3007 /* ---------------------------------------------------------------------------
3009 - usually called inside a signal handler so it mustn't do anything fancy.
3010 ------------------------------------------------------------------------ */
3013 interruptStgRts(void)
3019 /* -----------------------------------------------------------------------------
3022 This is for use when we raise an exception in another thread, which
3024 This has nothing to do with the UnblockThread event in GranSim. -- HWL
3025 -------------------------------------------------------------------------- */
3027 #if defined(GRAN) || defined(PAR)
3029 NB: only the type of the blocking queue is different in GranSim and GUM
3030 the operations on the queue-elements are the same
3031 long live polymorphism!
3033 Locks: sched_mutex is held upon entry and exit.
3037 unblockThread(StgTSO *tso)
3039 StgBlockingQueueElement *t, **last;
3041 switch (tso->why_blocked) {
3044 return; /* not blocked */
3047 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
3049 StgBlockingQueueElement *last_tso = END_BQ_QUEUE;
3050 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
3052 last = (StgBlockingQueueElement **)&mvar->head;
3053 for (t = (StgBlockingQueueElement *)mvar->head;
3055 last = &t->link, last_tso = t, t = t->link) {
3056 if (t == (StgBlockingQueueElement *)tso) {
3057 *last = (StgBlockingQueueElement *)tso->link;
3058 if (mvar->tail == tso) {
3059 mvar->tail = (StgTSO *)last_tso;
3064 barf("unblockThread (MVAR): TSO not found");
3067 case BlockedOnBlackHole:
3068 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
3070 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
3072 last = &bq->blocking_queue;
3073 for (t = bq->blocking_queue;
3075 last = &t->link, t = t->link) {
3076 if (t == (StgBlockingQueueElement *)tso) {
3077 *last = (StgBlockingQueueElement *)tso->link;
3081 barf("unblockThread (BLACKHOLE): TSO not found");
3084 case BlockedOnException:
3086 StgTSO *target = tso->block_info.tso;
3088 ASSERT(get_itbl(target)->type == TSO);
3090 if (target->what_next == ThreadRelocated) {
3091 target = target->link;
3092 ASSERT(get_itbl(target)->type == TSO);
3095 ASSERT(target->blocked_exceptions != NULL);
3097 last = (StgBlockingQueueElement **)&target->blocked_exceptions;
3098 for (t = (StgBlockingQueueElement *)target->blocked_exceptions;
3100 last = &t->link, t = t->link) {
3101 ASSERT(get_itbl(t)->type == TSO);
3102 if (t == (StgBlockingQueueElement *)tso) {
3103 *last = (StgBlockingQueueElement *)tso->link;
3107 barf("unblockThread (Exception): TSO not found");
3111 case BlockedOnWrite:
3113 /* take TSO off blocked_queue */
3114 StgBlockingQueueElement *prev = NULL;
3115 for (t = (StgBlockingQueueElement *)blocked_queue_hd; t != END_BQ_QUEUE;
3116 prev = t, t = t->link) {
3117 if (t == (StgBlockingQueueElement *)tso) {
3119 blocked_queue_hd = (StgTSO *)t->link;
3120 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
3121 blocked_queue_tl = END_TSO_QUEUE;
3124 prev->link = t->link;
3125 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
3126 blocked_queue_tl = (StgTSO *)prev;
3132 barf("unblockThread (I/O): TSO not found");
3135 case BlockedOnDelay:
3137 /* take TSO off sleeping_queue */
3138 StgBlockingQueueElement *prev = NULL;
3139 for (t = (StgBlockingQueueElement *)sleeping_queue; t != END_BQ_QUEUE;
3140 prev = t, t = t->link) {
3141 if (t == (StgBlockingQueueElement *)tso) {
3143 sleeping_queue = (StgTSO *)t->link;
3145 prev->link = t->link;
3150 barf("unblockThread (I/O): TSO not found");
3154 barf("unblockThread");
3158 tso->link = END_TSO_QUEUE;
3159 tso->why_blocked = NotBlocked;
3160 tso->block_info.closure = NULL;
3161 PUSH_ON_RUN_QUEUE(tso);
3165 unblockThread(StgTSO *tso)
3169 /* To avoid locking unnecessarily. */
3170 if (tso->why_blocked == NotBlocked) {
3174 switch (tso->why_blocked) {
3177 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
3179 StgTSO *last_tso = END_TSO_QUEUE;
3180 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
3183 for (t = mvar->head; t != END_TSO_QUEUE;
3184 last = &t->link, last_tso = t, t = t->link) {
3187 if (mvar->tail == tso) {
3188 mvar->tail = last_tso;
3193 barf("unblockThread (MVAR): TSO not found");
3196 case BlockedOnBlackHole:
3197 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
3199 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
3201 last = &bq->blocking_queue;
3202 for (t = bq->blocking_queue; t != END_TSO_QUEUE;
3203 last = &t->link, t = t->link) {
3209 barf("unblockThread (BLACKHOLE): TSO not found");
3212 case BlockedOnException:
3214 StgTSO *target = tso->block_info.tso;
3216 ASSERT(get_itbl(target)->type == TSO);
3218 while (target->what_next == ThreadRelocated) {
3219 target = target->link;
3220 ASSERT(get_itbl(target)->type == TSO);
3223 ASSERT(target->blocked_exceptions != NULL);
3225 last = &target->blocked_exceptions;
3226 for (t = target->blocked_exceptions; t != END_TSO_QUEUE;
3227 last = &t->link, t = t->link) {
3228 ASSERT(get_itbl(t)->type == TSO);
3234 barf("unblockThread (Exception): TSO not found");
3238 case BlockedOnWrite:
3240 StgTSO *prev = NULL;
3241 for (t = blocked_queue_hd; t != END_TSO_QUEUE;
3242 prev = t, t = t->link) {
3245 blocked_queue_hd = t->link;
3246 if (blocked_queue_tl == t) {
3247 blocked_queue_tl = END_TSO_QUEUE;
3250 prev->link = t->link;
3251 if (blocked_queue_tl == t) {
3252 blocked_queue_tl = prev;
3258 barf("unblockThread (I/O): TSO not found");
3261 case BlockedOnDelay:
3263 StgTSO *prev = NULL;
3264 for (t = sleeping_queue; t != END_TSO_QUEUE;
3265 prev = t, t = t->link) {
3268 sleeping_queue = t->link;
3270 prev->link = t->link;
3275 barf("unblockThread (I/O): TSO not found");
3279 barf("unblockThread");
3283 tso->link = END_TSO_QUEUE;
3284 tso->why_blocked = NotBlocked;
3285 tso->block_info.closure = NULL;
3286 PUSH_ON_RUN_QUEUE(tso);
3290 /* -----------------------------------------------------------------------------
3293 * The following function implements the magic for raising an
3294 * asynchronous exception in an existing thread.
3296 * We first remove the thread from any queue on which it might be
3297 * blocked. The possible blockages are MVARs and BLACKHOLE_BQs.
3299 * We strip the stack down to the innermost CATCH_FRAME, building
3300 * thunks in the heap for all the active computations, so they can
3301 * be restarted if necessary. When we reach a CATCH_FRAME, we build
3302 * an application of the handler to the exception, and push it on
3303 * the top of the stack.
3305 * How exactly do we save all the active computations? We create an
3306 * AP_STACK for every UpdateFrame on the stack. Entering one of these
3307 * AP_STACKs pushes everything from the corresponding update frame
3308 * upwards onto the stack. (Actually, it pushes everything up to the
3309 * next update frame plus a pointer to the next AP_STACK object.
3310 * Entering the next AP_STACK object pushes more onto the stack until we
3311 * reach the last AP_STACK object - at which point the stack should look
3312 * exactly as it did when we killed the TSO and we can continue
3313 * execution by entering the closure on top of the stack.
3315 * We can also kill a thread entirely - this happens if either (a) the
3316 * exception passed to raiseAsync is NULL, or (b) there's no
3317 * CATCH_FRAME on the stack. In either case, we strip the entire
3318 * stack and replace the thread with a zombie.
3320 * Locks: sched_mutex held upon entry nor exit.
3322 * -------------------------------------------------------------------------- */
3325 deleteThread(StgTSO *tso)
3327 raiseAsync(tso,NULL);
3331 raiseAsyncWithLock(StgTSO *tso, StgClosure *exception)
3333 /* When raising async exs from contexts where sched_mutex isn't held;
3334 use raiseAsyncWithLock(). */
3335 ACQUIRE_LOCK(&sched_mutex);
3336 raiseAsync(tso,exception);
3337 RELEASE_LOCK(&sched_mutex);
3341 raiseAsync(StgTSO *tso, StgClosure *exception)
3343 StgRetInfoTable *info;
3346 // Thread already dead?
3347 if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) {
3352 sched_belch("raising exception in thread %ld.", tso->id));
3354 // Remove it from any blocking queues
3359 // The stack freezing code assumes there's a closure pointer on
3360 // the top of the stack, so we have to arrange that this is the case...
3362 if (sp[0] == (W_)&stg_enter_info) {
3366 sp[0] = (W_)&stg_dummy_ret_closure;
3372 // 1. Let the top of the stack be the "current closure"
3374 // 2. Walk up the stack until we find either an UPDATE_FRAME or a
3377 // 3. If it's an UPDATE_FRAME, then make an AP_STACK containing the
3378 // current closure applied to the chunk of stack up to (but not
3379 // including) the update frame. This closure becomes the "current
3380 // closure". Go back to step 2.
3382 // 4. If it's a CATCH_FRAME, then leave the exception handler on
3383 // top of the stack applied to the exception.
3385 // 5. If it's a STOP_FRAME, then kill the thread.
3390 info = get_ret_itbl((StgClosure *)frame);
3392 while (info->i.type != UPDATE_FRAME
3393 && (info->i.type != CATCH_FRAME || exception == NULL)
3394 && info->i.type != STOP_FRAME) {
3395 frame += stack_frame_sizeW((StgClosure *)frame);
3396 info = get_ret_itbl((StgClosure *)frame);
3399 switch (info->i.type) {
3402 // If we find a CATCH_FRAME, and we've got an exception to raise,
3403 // then build the THUNK raise(exception), and leave it on
3404 // top of the CATCH_FRAME ready to enter.
3408 StgCatchFrame *cf = (StgCatchFrame *)frame;
3412 // we've got an exception to raise, so let's pass it to the
3413 // handler in this frame.
3415 raise = (StgClosure *)allocate(sizeofW(StgClosure)+1);
3416 TICK_ALLOC_SE_THK(1,0);
3417 SET_HDR(raise,&stg_raise_info,cf->header.prof.ccs);
3418 raise->payload[0] = exception;
3420 // throw away the stack from Sp up to the CATCH_FRAME.
3424 /* Ensure that async excpetions are blocked now, so we don't get
3425 * a surprise exception before we get around to executing the
3428 if (tso->blocked_exceptions == NULL) {
3429 tso->blocked_exceptions = END_TSO_QUEUE;
3432 /* Put the newly-built THUNK on top of the stack, ready to execute
3433 * when the thread restarts.
3436 sp[-1] = (W_)&stg_enter_info;
3438 tso->what_next = ThreadRunGHC;
3439 IF_DEBUG(sanity, checkTSO(tso));
3448 // First build an AP_STACK consisting of the stack chunk above the
3449 // current update frame, with the top word on the stack as the
3452 words = frame - sp - 1;
3453 ap = (StgAP_STACK *)allocate(PAP_sizeW(words));
3456 ap->fun = (StgClosure *)sp[0];
3458 for(i=0; i < (nat)words; ++i) {
3459 ap->payload[i] = (StgClosure *)*sp++;
3462 SET_HDR(ap,&stg_AP_STACK_info,
3463 ((StgClosure *)frame)->header.prof.ccs /* ToDo */);
3464 TICK_ALLOC_UP_THK(words+1,0);
3467 fprintf(stderr, "scheduler: Updating ");
3468 printPtr((P_)((StgUpdateFrame *)frame)->updatee);
3469 fprintf(stderr, " with ");
3470 printObj((StgClosure *)ap);
3473 // Replace the updatee with an indirection - happily
3474 // this will also wake up any threads currently
3475 // waiting on the result.
3477 // Warning: if we're in a loop, more than one update frame on
3478 // the stack may point to the same object. Be careful not to
3479 // overwrite an IND_OLDGEN in this case, because we'll screw
3480 // up the mutable lists. To be on the safe side, don't
3481 // overwrite any kind of indirection at all. See also
3482 // threadSqueezeStack in GC.c, where we have to make a similar
3485 if (!closure_IND(((StgUpdateFrame *)frame)->updatee)) {
3486 // revert the black hole
3487 UPD_IND_NOLOCK(((StgUpdateFrame *)frame)->updatee,ap);
3489 sp += sizeofW(StgUpdateFrame) - 1;
3490 sp[0] = (W_)ap; // push onto stack
3495 // We've stripped the entire stack, the thread is now dead.
3496 sp += sizeofW(StgStopFrame);
3497 tso->what_next = ThreadKilled;
3508 /* -----------------------------------------------------------------------------
3509 resurrectThreads is called after garbage collection on the list of
3510 threads found to be garbage. Each of these threads will be woken
3511 up and sent a signal: BlockedOnDeadMVar if the thread was blocked
3512 on an MVar, or NonTermination if the thread was blocked on a Black
3515 Locks: sched_mutex isn't held upon entry nor exit.
3516 -------------------------------------------------------------------------- */
3519 resurrectThreads( StgTSO *threads )
3523 for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
3524 next = tso->global_link;
3525 tso->global_link = all_threads;
3527 IF_DEBUG(scheduler, sched_belch("resurrecting thread %d", tso->id));
3529 switch (tso->why_blocked) {
3531 case BlockedOnException:
3532 /* Called by GC - sched_mutex lock is currently held. */
3533 raiseAsync(tso,(StgClosure *)BlockedOnDeadMVar_closure);
3535 case BlockedOnBlackHole:
3536 raiseAsync(tso,(StgClosure *)NonTermination_closure);
3539 /* This might happen if the thread was blocked on a black hole
3540 * belonging to a thread that we've just woken up (raiseAsync
3541 * can wake up threads, remember...).
3545 barf("resurrectThreads: thread blocked in a strange way");
3550 /* -----------------------------------------------------------------------------
3551 * Blackhole detection: if we reach a deadlock, test whether any
3552 * threads are blocked on themselves. Any threads which are found to
3553 * be self-blocked get sent a NonTermination exception.
3555 * This is only done in a deadlock situation in order to avoid
3556 * performance overhead in the normal case.
3558 * Locks: sched_mutex is held upon entry and exit.
3559 * -------------------------------------------------------------------------- */
3562 detectBlackHoles( void )
3564 StgTSO *tso = all_threads;
3566 StgClosure *blocked_on;
3567 StgRetInfoTable *info;
3569 for (tso = all_threads; tso != END_TSO_QUEUE; tso = tso->global_link) {
3571 while (tso->what_next == ThreadRelocated) {
3573 ASSERT(get_itbl(tso)->type == TSO);
3576 if (tso->why_blocked != BlockedOnBlackHole) {
3579 blocked_on = tso->block_info.closure;
3581 frame = (StgClosure *)tso->sp;
3584 info = get_ret_itbl(frame);
3585 switch (info->i.type) {
3587 if (((StgUpdateFrame *)frame)->updatee == blocked_on) {
3588 /* We are blocking on one of our own computations, so
3589 * send this thread the NonTermination exception.
3592 sched_belch("thread %d is blocked on itself", tso->id));
3593 raiseAsync(tso, (StgClosure *)NonTermination_closure);
3597 frame = (StgClosure *) ((StgUpdateFrame *)frame + 1);
3603 // normal stack frames; do nothing except advance the pointer
3605 (StgPtr)frame += stack_frame_sizeW(frame);
3612 //@node Debugging Routines, Index, Exception Handling Routines, Main scheduling code
3613 //@subsection Debugging Routines
3615 /* -----------------------------------------------------------------------------
3616 * Debugging: why is a thread blocked
3617 * [Also provides useful information when debugging threaded programs
3618 * at the Haskell source code level, so enable outside of DEBUG. --sof 7/02]
3619 -------------------------------------------------------------------------- */
3623 printThreadBlockage(StgTSO *tso)
3625 switch (tso->why_blocked) {
3627 fprintf(stderr,"is blocked on read from fd %d", tso->block_info.fd);
3629 case BlockedOnWrite:
3630 fprintf(stderr,"is blocked on write to fd %d", tso->block_info.fd);
3632 case BlockedOnDelay:
3633 fprintf(stderr,"is blocked until %d", tso->block_info.target);
3636 fprintf(stderr,"is blocked on an MVar");
3638 case BlockedOnException:
3639 fprintf(stderr,"is blocked on delivering an exception to thread %d",
3640 tso->block_info.tso->id);
3642 case BlockedOnBlackHole:
3643 fprintf(stderr,"is blocked on a black hole");
3646 fprintf(stderr,"is not blocked");
3650 fprintf(stderr,"is blocked on global address; local FM_BQ is %p (%s)",
3651 tso->block_info.closure, info_type(tso->block_info.closure));
3653 case BlockedOnGA_NoSend:
3654 fprintf(stderr,"is blocked on global address (no send); local FM_BQ is %p (%s)",
3655 tso->block_info.closure, info_type(tso->block_info.closure));
3658 #if defined(RTS_SUPPORTS_THREADS)
3659 case BlockedOnCCall:
3660 fprintf(stderr,"is blocked on an external call");
3662 case BlockedOnCCall_NoUnblockExc:
3663 fprintf(stderr,"is blocked on an external call (exceptions were already blocked)");
3667 barf("printThreadBlockage: strange tso->why_blocked: %d for TSO %d (%d)",
3668 tso->why_blocked, tso->id, tso);
3674 printThreadStatus(StgTSO *tso)
3676 switch (tso->what_next) {
3678 fprintf(stderr,"has been killed");
3680 case ThreadComplete:
3681 fprintf(stderr,"has completed");
3684 printThreadBlockage(tso);
3689 printAllThreads(void)
3695 char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN];
3696 ullong_format_string(TIME_ON_PROC(CurrentProc),
3697 time_string, rtsFalse/*no commas!*/);
3699 fprintf(stderr, "all threads at [%s]:\n", time_string);
3701 char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN];
3702 ullong_format_string(CURRENT_TIME,
3703 time_string, rtsFalse/*no commas!*/);
3705 fprintf(stderr,"all threads at [%s]:\n", time_string);
3707 fprintf(stderr,"all threads:\n");
3710 for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
3711 fprintf(stderr, "\tthread %d @ %p ", t->id, (void *)t);
3712 label = lookupThreadLabel((StgWord)t);
3713 if (label) fprintf(stderr,"[\"%s\"] ",(char *)label);
3714 printThreadStatus(t);
3715 fprintf(stderr,"\n");
3722 Print a whole blocking queue attached to node (debugging only).
3727 print_bq (StgClosure *node)
3729 StgBlockingQueueElement *bqe;
3733 fprintf(stderr,"## BQ of closure %p (%s): ",
3734 node, info_type(node));
3736 /* should cover all closures that may have a blocking queue */
3737 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3738 get_itbl(node)->type == FETCH_ME_BQ ||
3739 get_itbl(node)->type == RBH ||
3740 get_itbl(node)->type == MVAR);
3742 ASSERT(node!=(StgClosure*)NULL); // sanity check
3744 print_bqe(((StgBlockingQueue*)node)->blocking_queue);
3748 Print a whole blocking queue starting with the element bqe.
3751 print_bqe (StgBlockingQueueElement *bqe)
3756 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3758 for (end = (bqe==END_BQ_QUEUE);
3759 !end; // iterate until bqe points to a CONSTR
3760 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE),
3761 bqe = end ? END_BQ_QUEUE : bqe->link) {
3762 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3763 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
3764 /* types of closures that may appear in a blocking queue */
3765 ASSERT(get_itbl(bqe)->type == TSO ||
3766 get_itbl(bqe)->type == BLOCKED_FETCH ||
3767 get_itbl(bqe)->type == CONSTR);
3768 /* only BQs of an RBH end with an RBH_Save closure */
3769 //ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3771 switch (get_itbl(bqe)->type) {
3773 fprintf(stderr," TSO %u (%x),",
3774 ((StgTSO *)bqe)->id, ((StgTSO *)bqe));
3777 fprintf(stderr," BF (node=%p, ga=((%x, %d, %x)),",
3778 ((StgBlockedFetch *)bqe)->node,
3779 ((StgBlockedFetch *)bqe)->ga.payload.gc.gtid,
3780 ((StgBlockedFetch *)bqe)->ga.payload.gc.slot,
3781 ((StgBlockedFetch *)bqe)->ga.weight);
3784 fprintf(stderr," %s (IP %p),",
3785 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3786 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3787 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3788 "RBH_Save_?"), get_itbl(bqe));
3791 barf("Unexpected closure type %s in blocking queue", // of %p (%s)",
3792 info_type((StgClosure *)bqe)); // , node, info_type(node));
3796 fputc('\n', stderr);
3798 # elif defined(GRAN)
3800 print_bq (StgClosure *node)
3802 StgBlockingQueueElement *bqe;
3803 PEs node_loc, tso_loc;
3806 /* should cover all closures that may have a blocking queue */
3807 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3808 get_itbl(node)->type == FETCH_ME_BQ ||
3809 get_itbl(node)->type == RBH);
3811 ASSERT(node!=(StgClosure*)NULL); // sanity check
3812 node_loc = where_is(node);
3814 fprintf(stderr,"## BQ of closure %p (%s) on [PE %d]: ",
3815 node, info_type(node), node_loc);
3818 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3820 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
3821 !end; // iterate until bqe points to a CONSTR
3822 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
3823 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3824 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
3825 /* types of closures that may appear in a blocking queue */
3826 ASSERT(get_itbl(bqe)->type == TSO ||
3827 get_itbl(bqe)->type == CONSTR);
3828 /* only BQs of an RBH end with an RBH_Save closure */
3829 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3831 tso_loc = where_is((StgClosure *)bqe);
3832 switch (get_itbl(bqe)->type) {
3834 fprintf(stderr," TSO %d (%p) on [PE %d],",
3835 ((StgTSO *)bqe)->id, (StgTSO *)bqe, tso_loc);
3838 fprintf(stderr," %s (IP %p),",
3839 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3840 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3841 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3842 "RBH_Save_?"), get_itbl(bqe));
3845 barf("Unexpected closure type %s in blocking queue of %p (%s)",
3846 info_type((StgClosure *)bqe), node, info_type(node));
3850 fputc('\n', stderr);
3854 Nice and easy: only TSOs on the blocking queue
3857 print_bq (StgClosure *node)
3861 ASSERT(node!=(StgClosure*)NULL); // sanity check
3862 for (tso = ((StgBlockingQueue*)node)->blocking_queue;
3863 tso != END_TSO_QUEUE;
3865 ASSERT(tso!=NULL && tso!=END_TSO_QUEUE); // sanity check
3866 ASSERT(get_itbl(tso)->type == TSO); // guess what, sanity check
3867 fprintf(stderr," TSO %d (%p),", tso->id, tso);
3869 fputc('\n', stderr);
3880 for (i=0, tso=run_queue_hd;
3881 tso != END_TSO_QUEUE;
3890 sched_belch(char *s, ...)
3895 fprintf(stderr, "scheduler (task %ld): ", osThreadId());
3897 fprintf(stderr, "== ");
3899 fprintf(stderr, "scheduler: ");
3901 vfprintf(stderr, s, ap);
3902 fprintf(stderr, "\n");
3909 //@node Index, , Debugging Routines, Main scheduling code
3913 //* StgMainThread:: @cindex\s-+StgMainThread
3914 //* awaken_blocked_queue:: @cindex\s-+awaken_blocked_queue
3915 //* blocked_queue_hd:: @cindex\s-+blocked_queue_hd
3916 //* blocked_queue_tl:: @cindex\s-+blocked_queue_tl
3917 //* context_switch:: @cindex\s-+context_switch
3918 //* createThread:: @cindex\s-+createThread
3919 //* gc_pending_cond:: @cindex\s-+gc_pending_cond
3920 //* initScheduler:: @cindex\s-+initScheduler
3921 //* interrupted:: @cindex\s-+interrupted
3922 //* next_thread_id:: @cindex\s-+next_thread_id
3923 //* print_bq:: @cindex\s-+print_bq
3924 //* run_queue_hd:: @cindex\s-+run_queue_hd
3925 //* run_queue_tl:: @cindex\s-+run_queue_tl
3926 //* sched_mutex:: @cindex\s-+sched_mutex
3927 //* schedule:: @cindex\s-+schedule
3928 //* take_off_run_queue:: @cindex\s-+take_off_run_queue
3929 //* term_mutex:: @cindex\s-+term_mutex