1 /* ---------------------------------------------------------------------------
2 * $Id: Schedule.c,v 1.172 2003/07/12 00:09:15 sof 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"
99 #include "ThreadLabels.h"
101 #include "Proftimer.h"
102 #include "ProfHeap.h"
104 #if defined(GRAN) || defined(PAR)
105 # include "GranSimRts.h"
106 # include "GranSim.h"
107 # include "ParallelRts.h"
108 # include "Parallel.h"
109 # include "ParallelDebug.h"
110 # include "FetchMe.h"
114 #include "Capability.h"
115 #include "OSThreads.h"
118 #ifdef HAVE_SYS_TYPES_H
119 #include <sys/types.h>
129 //@node Variables and Data structures, Prototypes, Includes, Main scheduling code
130 //@subsection Variables and Data structures
132 /* Main thread queue.
133 * Locks required: sched_mutex.
135 StgMainThread *main_threads = NULL;
138 // Pointer to the thread that executes main
139 // When this thread is finished, the program terminates
140 // by calling shutdownHaskellAndExit.
141 // It would be better to add a call to shutdownHaskellAndExit
142 // to the Main.main wrapper and to remove this hack.
143 StgMainThread *main_main_thread = NULL;
147 * Locks required: sched_mutex.
151 StgTSO* ActiveTSO = NULL; /* for assigning system costs; GranSim-Light only */
152 /* rtsTime TimeOfNextEvent, EndOfTimeSlice; now in GranSim.c */
155 In GranSim we have a runnable and a blocked queue for each processor.
156 In order to minimise code changes new arrays run_queue_hds/tls
157 are created. run_queue_hd is then a short cut (macro) for
158 run_queue_hds[CurrentProc] (see GranSim.h).
161 StgTSO *run_queue_hds[MAX_PROC], *run_queue_tls[MAX_PROC];
162 StgTSO *blocked_queue_hds[MAX_PROC], *blocked_queue_tls[MAX_PROC];
163 StgTSO *ccalling_threadss[MAX_PROC];
164 /* We use the same global list of threads (all_threads) in GranSim as in
165 the std RTS (i.e. we are cheating). However, we don't use this list in
166 the GranSim specific code at the moment (so we are only potentially
171 StgTSO *run_queue_hd = NULL;
172 StgTSO *run_queue_tl = NULL;
173 StgTSO *blocked_queue_hd = NULL;
174 StgTSO *blocked_queue_tl = NULL;
175 StgTSO *sleeping_queue = NULL; /* perhaps replace with a hash table? */
179 /* Linked list of all threads.
180 * Used for detecting garbage collected threads.
182 StgTSO *all_threads = NULL;
184 /* When a thread performs a safe C call (_ccall_GC, using old
185 * terminology), it gets put on the suspended_ccalling_threads
186 * list. Used by the garbage collector.
188 static StgTSO *suspended_ccalling_threads;
190 static StgTSO *threadStackOverflow(StgTSO *tso);
192 /* KH: The following two flags are shared memory locations. There is no need
193 to lock them, since they are only unset at the end of a scheduler
197 /* flag set by signal handler to precipitate a context switch */
198 //@cindex context_switch
199 nat context_switch = 0;
201 /* if this flag is set as well, give up execution */
202 //@cindex interrupted
203 rtsBool interrupted = rtsFalse;
205 /* Next thread ID to allocate.
206 * Locks required: thread_id_mutex
208 //@cindex next_thread_id
209 static StgThreadID next_thread_id = 1;
212 * Pointers to the state of the current thread.
213 * Rule of thumb: if CurrentTSO != NULL, then we're running a Haskell
214 * thread. If CurrentTSO == NULL, then we're at the scheduler level.
217 /* The smallest stack size that makes any sense is:
218 * RESERVED_STACK_WORDS (so we can get back from the stack overflow)
219 * + sizeofW(StgStopFrame) (the stg_stop_thread_info frame)
220 * + 1 (the closure to enter)
222 * + 1 (spare slot req'd by stg_ap_v_ret)
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) + 3)
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 #if defined(RTS_USER_SIGNALS)
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 #if defined(RTS_USER_SIGNALS)
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 * ------------------------------------------------------------------------- */
1499 forkProcess(StgTSO* tso)
1501 #ifndef mingw32_TARGET_OS
1507 IF_DEBUG(scheduler,sched_belch("forking!"));
1510 if (pid) { /* parent */
1512 /* just return the pid */
1514 } else { /* child */
1515 /* wipe all other threads */
1516 run_queue_hd = run_queue_tl = tso;
1517 tso->link = END_TSO_QUEUE;
1519 /* When clearing out the threads, we need to ensure
1520 that a 'main thread' is left behind; if there isn't,
1521 the Scheduler will shutdown next time it is entered.
1523 ==> we don't kill a thread that's on the main_threads
1524 list (nor the current thread.)
1526 [ Attempts at implementing the more ambitious scheme of
1527 killing the main_threads also, and then adding the
1528 current thread onto the main_threads list if it wasn't
1529 there already, failed -- waitThread() (for one) wasn't
1530 up to it. If it proves to be desirable to also kill
1531 the main threads, then this scheme will have to be
1532 revisited (and fully debugged!)
1537 /* DO NOT TOUCH THE QUEUES directly because most of the code around
1538 us is picky about finding the thread still in its queue when
1539 handling the deleteThread() */
1541 for (t = all_threads; t != END_TSO_QUEUE; t = next) {
1544 /* Don't kill the current thread.. */
1545 if (t->id == tso->id) continue;
1547 /* ..or a main thread */
1548 for (m = main_threads; m != NULL; m = m->link) {
1549 if (m->tso->id == t->id) {
1561 barf("forkProcess#: primop not implemented for mingw32, sorry! (%u)\n", tso->id);
1562 /* pointlessly printing out the TSOs 'id' to avoid CC unused warning. */
1564 #endif /* mingw32 */
1567 /* ---------------------------------------------------------------------------
1568 * deleteAllThreads(): kill all the live threads.
1570 * This is used when we catch a user interrupt (^C), before performing
1571 * any necessary cleanups and running finalizers.
1573 * Locks: sched_mutex held.
1574 * ------------------------------------------------------------------------- */
1577 deleteAllThreads ( void )
1580 IF_DEBUG(scheduler,sched_belch("deleting all threads"));
1581 for (t = all_threads; t != END_TSO_QUEUE; t = next) {
1582 next = t->global_link;
1585 run_queue_hd = run_queue_tl = END_TSO_QUEUE;
1586 blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
1587 sleeping_queue = END_TSO_QUEUE;
1590 /* startThread and insertThread are now in GranSim.c -- HWL */
1593 //@node Suspend and Resume, Run queue code, Main scheduling loop, Main scheduling code
1594 //@subsection Suspend and Resume
1596 /* ---------------------------------------------------------------------------
1597 * Suspending & resuming Haskell threads.
1599 * When making a "safe" call to C (aka _ccall_GC), the task gives back
1600 * its capability before calling the C function. This allows another
1601 * task to pick up the capability and carry on running Haskell
1602 * threads. It also means that if the C call blocks, it won't lock
1605 * The Haskell thread making the C call is put to sleep for the
1606 * duration of the call, on the susepended_ccalling_threads queue. We
1607 * give out a token to the task, which it can use to resume the thread
1608 * on return from the C function.
1609 * ------------------------------------------------------------------------- */
1612 suspendThread( StgRegTable *reg,
1614 #if !defined(RTS_SUPPORTS_THREADS) && !defined(DEBUG)
1622 /* assume that *reg is a pointer to the StgRegTable part
1625 cap = (Capability *)((void *)reg - sizeof(StgFunTable));
1627 ACQUIRE_LOCK(&sched_mutex);
1630 sched_belch("thread %d did a _ccall_gc (is_concurrent: %d)", cap->r.rCurrentTSO->id,concCall));
1632 // XXX this might not be necessary --SDM
1633 cap->r.rCurrentTSO->what_next = ThreadRunGHC;
1635 threadPaused(cap->r.rCurrentTSO);
1636 cap->r.rCurrentTSO->link = suspended_ccalling_threads;
1637 suspended_ccalling_threads = cap->r.rCurrentTSO;
1639 #if defined(RTS_SUPPORTS_THREADS)
1640 if(cap->r.rCurrentTSO->blocked_exceptions == NULL)
1642 cap->r.rCurrentTSO->why_blocked = BlockedOnCCall;
1643 cap->r.rCurrentTSO->blocked_exceptions = END_TSO_QUEUE;
1647 cap->r.rCurrentTSO->why_blocked = BlockedOnCCall_NoUnblockExc;
1651 /* Use the thread ID as the token; it should be unique */
1652 tok = cap->r.rCurrentTSO->id;
1654 /* Hand back capability */
1655 releaseCapability(cap);
1657 #if defined(RTS_SUPPORTS_THREADS)
1658 /* Preparing to leave the RTS, so ensure there's a native thread/task
1659 waiting to take over.
1661 IF_DEBUG(scheduler, sched_belch("worker thread (%d, osthread %p): leaving RTS", tok, osThreadId()));
1662 //if (concCall) { // implementing "safe" as opposed to "threadsafe" is more difficult
1663 startTask(taskStart);
1667 /* Other threads _might_ be available for execution; signal this */
1669 RELEASE_LOCK(&sched_mutex);
1674 resumeThread( StgInt tok,
1675 rtsBool concCall STG_UNUSED )
1677 StgTSO *tso, **prev;
1680 #if defined(RTS_SUPPORTS_THREADS)
1681 /* Wait for permission to re-enter the RTS with the result. */
1682 ACQUIRE_LOCK(&sched_mutex);
1683 grabReturnCapability(&sched_mutex, &cap);
1685 IF_DEBUG(scheduler, sched_belch("worker thread (%d, osthread %p): re-entering RTS", tok, osThreadId()));
1687 grabCapability(&cap);
1690 /* Remove the thread off of the suspended list */
1691 prev = &suspended_ccalling_threads;
1692 for (tso = suspended_ccalling_threads;
1693 tso != END_TSO_QUEUE;
1694 prev = &tso->link, tso = tso->link) {
1695 if (tso->id == (StgThreadID)tok) {
1700 if (tso == END_TSO_QUEUE) {
1701 barf("resumeThread: thread not found");
1703 tso->link = END_TSO_QUEUE;
1705 #if defined(RTS_SUPPORTS_THREADS)
1706 if(tso->why_blocked == BlockedOnCCall)
1708 awakenBlockedQueueNoLock(tso->blocked_exceptions);
1709 tso->blocked_exceptions = NULL;
1713 /* Reset blocking status */
1714 tso->why_blocked = NotBlocked;
1716 cap->r.rCurrentTSO = tso;
1717 #if defined(RTS_SUPPORTS_THREADS)
1718 RELEASE_LOCK(&sched_mutex);
1724 /* ---------------------------------------------------------------------------
1726 * ------------------------------------------------------------------------ */
1727 static void unblockThread(StgTSO *tso);
1729 /* ---------------------------------------------------------------------------
1730 * Comparing Thread ids.
1732 * This is used from STG land in the implementation of the
1733 * instances of Eq/Ord for ThreadIds.
1734 * ------------------------------------------------------------------------ */
1737 cmp_thread(StgPtr tso1, StgPtr tso2)
1739 StgThreadID id1 = ((StgTSO *)tso1)->id;
1740 StgThreadID id2 = ((StgTSO *)tso2)->id;
1742 if (id1 < id2) return (-1);
1743 if (id1 > id2) return 1;
1747 /* ---------------------------------------------------------------------------
1748 * Fetching the ThreadID from an StgTSO.
1750 * This is used in the implementation of Show for ThreadIds.
1751 * ------------------------------------------------------------------------ */
1753 rts_getThreadId(StgPtr tso)
1755 return ((StgTSO *)tso)->id;
1760 labelThread(StgPtr tso, char *label)
1765 /* Caveat: Once set, you can only set the thread name to "" */
1766 len = strlen(label)+1;
1767 buf = stgMallocBytes(len * sizeof(char), "Schedule.c:labelThread()");
1768 strncpy(buf,label,len);
1769 /* Update will free the old memory for us */
1770 updateThreadLabel((StgWord)tso,buf);
1774 /* ---------------------------------------------------------------------------
1775 Create a new thread.
1777 The new thread starts with the given stack size. Before the
1778 scheduler can run, however, this thread needs to have a closure
1779 (and possibly some arguments) pushed on its stack. See
1780 pushClosure() in Schedule.h.
1782 createGenThread() and createIOThread() (in SchedAPI.h) are
1783 convenient packaged versions of this function.
1785 currently pri (priority) is only used in a GRAN setup -- HWL
1786 ------------------------------------------------------------------------ */
1787 //@cindex createThread
1789 /* currently pri (priority) is only used in a GRAN setup -- HWL */
1791 createThread(nat size, StgInt pri)
1794 createThread(nat size)
1801 /* First check whether we should create a thread at all */
1803 /* check that no more than RtsFlags.ParFlags.maxThreads threads are created */
1804 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads) {
1806 belch("{createThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
1807 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
1808 return END_TSO_QUEUE;
1814 ASSERT(!RtsFlags.GranFlags.Light || CurrentProc==0);
1817 // ToDo: check whether size = stack_size - TSO_STRUCT_SIZEW
1819 /* catch ridiculously small stack sizes */
1820 if (size < MIN_STACK_WORDS + TSO_STRUCT_SIZEW) {
1821 size = MIN_STACK_WORDS + TSO_STRUCT_SIZEW;
1824 stack_size = size - TSO_STRUCT_SIZEW;
1826 tso = (StgTSO *)allocate(size);
1827 TICK_ALLOC_TSO(stack_size, 0);
1829 SET_HDR(tso, &stg_TSO_info, CCS_SYSTEM);
1831 SET_GRAN_HDR(tso, ThisPE);
1834 // Always start with the compiled code evaluator
1835 tso->what_next = ThreadRunGHC;
1837 /* tso->id needs to be unique. For now we use a heavyweight mutex to
1838 * protect the increment operation on next_thread_id.
1839 * In future, we could use an atomic increment instead.
1841 ACQUIRE_LOCK(&thread_id_mutex);
1842 tso->id = next_thread_id++;
1843 RELEASE_LOCK(&thread_id_mutex);
1845 tso->why_blocked = NotBlocked;
1846 tso->blocked_exceptions = NULL;
1848 tso->stack_size = stack_size;
1849 tso->max_stack_size = round_to_mblocks(RtsFlags.GcFlags.maxStkSize)
1851 tso->sp = (P_)&(tso->stack) + stack_size;
1854 tso->prof.CCCS = CCS_MAIN;
1857 /* put a stop frame on the stack */
1858 tso->sp -= sizeofW(StgStopFrame);
1859 SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_SYSTEM);
1862 tso->link = END_TSO_QUEUE;
1863 /* uses more flexible routine in GranSim */
1864 insertThread(tso, CurrentProc);
1866 /* In a non-GranSim setup the pushing of a TSO onto the runq is separated
1872 if (RtsFlags.GranFlags.GranSimStats.Full)
1873 DumpGranEvent(GR_START,tso);
1875 if (RtsFlags.ParFlags.ParStats.Full)
1876 DumpGranEvent(GR_STARTQ,tso);
1877 /* HACk to avoid SCHEDULE
1881 /* Link the new thread on the global thread list.
1883 tso->global_link = all_threads;
1887 tso->dist.priority = MandatoryPriority; //by default that is...
1891 tso->gran.pri = pri;
1893 tso->gran.magic = TSO_MAGIC; // debugging only
1895 tso->gran.sparkname = 0;
1896 tso->gran.startedat = CURRENT_TIME;
1897 tso->gran.exported = 0;
1898 tso->gran.basicblocks = 0;
1899 tso->gran.allocs = 0;
1900 tso->gran.exectime = 0;
1901 tso->gran.fetchtime = 0;
1902 tso->gran.fetchcount = 0;
1903 tso->gran.blocktime = 0;
1904 tso->gran.blockcount = 0;
1905 tso->gran.blockedat = 0;
1906 tso->gran.globalsparks = 0;
1907 tso->gran.localsparks = 0;
1908 if (RtsFlags.GranFlags.Light)
1909 tso->gran.clock = Now; /* local clock */
1911 tso->gran.clock = 0;
1913 IF_DEBUG(gran,printTSO(tso));
1916 tso->par.magic = TSO_MAGIC; // debugging only
1918 tso->par.sparkname = 0;
1919 tso->par.startedat = CURRENT_TIME;
1920 tso->par.exported = 0;
1921 tso->par.basicblocks = 0;
1922 tso->par.allocs = 0;
1923 tso->par.exectime = 0;
1924 tso->par.fetchtime = 0;
1925 tso->par.fetchcount = 0;
1926 tso->par.blocktime = 0;
1927 tso->par.blockcount = 0;
1928 tso->par.blockedat = 0;
1929 tso->par.globalsparks = 0;
1930 tso->par.localsparks = 0;
1934 globalGranStats.tot_threads_created++;
1935 globalGranStats.threads_created_on_PE[CurrentProc]++;
1936 globalGranStats.tot_sq_len += spark_queue_len(CurrentProc);
1937 globalGranStats.tot_sq_probes++;
1939 // collect parallel global statistics (currently done together with GC stats)
1940 if (RtsFlags.ParFlags.ParStats.Global &&
1941 RtsFlags.GcFlags.giveStats > NO_GC_STATS) {
1942 //fprintf(stderr, "Creating thread %d @ %11.2f\n", tso->id, usertime());
1943 globalParStats.tot_threads_created++;
1949 belch("==__ schedule: Created TSO %d (%p);",
1950 CurrentProc, tso, tso->id));
1952 IF_PAR_DEBUG(verbose,
1953 belch("==__ schedule: Created TSO %d (%p); %d threads active",
1954 tso->id, tso, advisory_thread_count));
1956 IF_DEBUG(scheduler,sched_belch("created thread %ld, stack size = %lx words",
1957 tso->id, tso->stack_size));
1964 all parallel thread creation calls should fall through the following routine.
1967 createSparkThread(rtsSpark spark)
1969 ASSERT(spark != (rtsSpark)NULL);
1970 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads)
1972 barf("{createSparkThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
1973 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
1974 return END_TSO_QUEUE;
1978 tso = createThread(RtsFlags.GcFlags.initialStkSize);
1979 if (tso==END_TSO_QUEUE)
1980 barf("createSparkThread: Cannot create TSO");
1982 tso->priority = AdvisoryPriority;
1984 pushClosure(tso,spark);
1985 PUSH_ON_RUN_QUEUE(tso);
1986 advisory_thread_count++;
1993 Turn a spark into a thread.
1994 ToDo: fix for SMP (needs to acquire SCHED_MUTEX!)
1997 //@cindex activateSpark
1999 activateSpark (rtsSpark spark)
2003 tso = createSparkThread(spark);
2004 if (RtsFlags.ParFlags.ParStats.Full) {
2005 //ASSERT(run_queue_hd == END_TSO_QUEUE); // I think ...
2006 IF_PAR_DEBUG(verbose,
2007 belch("==^^ activateSpark: turning spark of closure %p (%s) into a thread",
2008 (StgClosure *)spark, info_type((StgClosure *)spark)));
2010 // ToDo: fwd info on local/global spark to thread -- HWL
2011 // tso->gran.exported = spark->exported;
2012 // tso->gran.locked = !spark->global;
2013 // tso->gran.sparkname = spark->name;
2019 static SchedulerStatus waitThread_(/*out*/StgMainThread* m
2020 #if defined(THREADED_RTS)
2021 , rtsBool blockWaiting
2026 /* ---------------------------------------------------------------------------
2029 * scheduleThread puts a thread on the head of the runnable queue.
2030 * This will usually be done immediately after a thread is created.
2031 * The caller of scheduleThread must create the thread using e.g.
2032 * createThread and push an appropriate closure
2033 * on this thread's stack before the scheduler is invoked.
2034 * ------------------------------------------------------------------------ */
2036 static void scheduleThread_ (StgTSO* tso);
2039 scheduleThread_(StgTSO *tso)
2041 // Precondition: sched_mutex must be held.
2043 /* Put the new thread on the head of the runnable queue. The caller
2044 * better push an appropriate closure on this thread's stack
2045 * beforehand. In the SMP case, the thread may start running as
2046 * soon as we release the scheduler lock below.
2048 PUSH_ON_RUN_QUEUE(tso);
2052 IF_DEBUG(scheduler,printTSO(tso));
2056 void scheduleThread(StgTSO* tso)
2058 ACQUIRE_LOCK(&sched_mutex);
2059 scheduleThread_(tso);
2060 RELEASE_LOCK(&sched_mutex);
2064 scheduleWaitThread(StgTSO* tso, /*[out]*/HaskellObj* ret)
2065 { // Precondition: sched_mutex must be held
2068 m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
2072 #if defined(RTS_SUPPORTS_THREADS)
2073 initCondition(&m->wakeup);
2076 /* Put the thread on the main-threads list prior to scheduling the TSO.
2077 Failure to do so introduces a race condition in the MT case (as
2078 identified by Wolfgang Thaller), whereby the new task/OS thread
2079 created by scheduleThread_() would complete prior to the thread
2080 that spawned it managed to put 'itself' on the main-threads list.
2081 The upshot of it all being that the worker thread wouldn't get to
2082 signal the completion of the its work item for the main thread to
2083 see (==> it got stuck waiting.) -- sof 6/02.
2085 IF_DEBUG(scheduler, sched_belch("waiting for thread (%d)\n", tso->id));
2087 m->link = main_threads;
2090 scheduleThread_(tso);
2091 #if defined(THREADED_RTS)
2092 return waitThread_(m, rtsTrue);
2094 return waitThread_(m);
2098 /* ---------------------------------------------------------------------------
2101 * Initialise the scheduler. This resets all the queues - if the
2102 * queues contained any threads, they'll be garbage collected at the
2105 * ------------------------------------------------------------------------ */
2109 term_handler(int sig STG_UNUSED)
2112 ACQUIRE_LOCK(&term_mutex);
2114 RELEASE_LOCK(&term_mutex);
2125 for (i=0; i<=MAX_PROC; i++) {
2126 run_queue_hds[i] = END_TSO_QUEUE;
2127 run_queue_tls[i] = END_TSO_QUEUE;
2128 blocked_queue_hds[i] = END_TSO_QUEUE;
2129 blocked_queue_tls[i] = END_TSO_QUEUE;
2130 ccalling_threadss[i] = END_TSO_QUEUE;
2131 sleeping_queue = END_TSO_QUEUE;
2134 run_queue_hd = END_TSO_QUEUE;
2135 run_queue_tl = END_TSO_QUEUE;
2136 blocked_queue_hd = END_TSO_QUEUE;
2137 blocked_queue_tl = END_TSO_QUEUE;
2138 sleeping_queue = END_TSO_QUEUE;
2141 suspended_ccalling_threads = END_TSO_QUEUE;
2143 main_threads = NULL;
2144 all_threads = END_TSO_QUEUE;
2149 RtsFlags.ConcFlags.ctxtSwitchTicks =
2150 RtsFlags.ConcFlags.ctxtSwitchTime / TICK_MILLISECS;
2152 #if defined(RTS_SUPPORTS_THREADS)
2153 /* Initialise the mutex and condition variables used by
2155 initMutex(&sched_mutex);
2156 initMutex(&term_mutex);
2157 initMutex(&thread_id_mutex);
2159 initCondition(&thread_ready_cond);
2163 initCondition(&gc_pending_cond);
2166 #if defined(RTS_SUPPORTS_THREADS)
2167 ACQUIRE_LOCK(&sched_mutex);
2170 /* Install the SIGHUP handler */
2173 struct sigaction action,oact;
2175 action.sa_handler = term_handler;
2176 sigemptyset(&action.sa_mask);
2177 action.sa_flags = 0;
2178 if (sigaction(SIGTERM, &action, &oact) != 0) {
2179 barf("can't install TERM handler");
2184 /* A capability holds the state a native thread needs in
2185 * order to execute STG code. At least one capability is
2186 * floating around (only SMP builds have more than one).
2190 #if defined(RTS_SUPPORTS_THREADS)
2191 /* start our haskell execution tasks */
2193 startTaskManager(RtsFlags.ParFlags.nNodes, taskStart);
2195 startTaskManager(0,taskStart);
2199 #if /* defined(SMP) ||*/ defined(PAR)
2203 #if defined(RTS_SUPPORTS_THREADS)
2204 RELEASE_LOCK(&sched_mutex);
2210 exitScheduler( void )
2212 #if defined(RTS_SUPPORTS_THREADS)
2215 shutting_down_scheduler = rtsTrue;
2218 /* -----------------------------------------------------------------------------
2219 Managing the per-task allocation areas.
2221 Each capability comes with an allocation area. These are
2222 fixed-length block lists into which allocation can be done.
2224 ToDo: no support for two-space collection at the moment???
2225 -------------------------------------------------------------------------- */
2227 /* -----------------------------------------------------------------------------
2228 * waitThread is the external interface for running a new computation
2229 * and waiting for the result.
2231 * In the non-SMP case, we create a new main thread, push it on the
2232 * main-thread stack, and invoke the scheduler to run it. The
2233 * scheduler will return when the top main thread on the stack has
2234 * completed or died, and fill in the necessary fields of the
2235 * main_thread structure.
2237 * In the SMP case, we create a main thread as before, but we then
2238 * create a new condition variable and sleep on it. When our new
2239 * main thread has completed, we'll be woken up and the status/result
2240 * will be in the main_thread struct.
2241 * -------------------------------------------------------------------------- */
2244 howManyThreadsAvail ( void )
2248 for (q = run_queue_hd; q != END_TSO_QUEUE; q = q->link)
2250 for (q = blocked_queue_hd; q != END_TSO_QUEUE; q = q->link)
2252 for (q = sleeping_queue; q != END_TSO_QUEUE; q = q->link)
2258 finishAllThreads ( void )
2261 while (run_queue_hd != END_TSO_QUEUE) {
2262 waitThread ( run_queue_hd, NULL);
2264 while (blocked_queue_hd != END_TSO_QUEUE) {
2265 waitThread ( blocked_queue_hd, NULL);
2267 while (sleeping_queue != END_TSO_QUEUE) {
2268 waitThread ( blocked_queue_hd, NULL);
2271 (blocked_queue_hd != END_TSO_QUEUE ||
2272 run_queue_hd != END_TSO_QUEUE ||
2273 sleeping_queue != END_TSO_QUEUE);
2277 waitThread(StgTSO *tso, /*out*/StgClosure **ret)
2280 SchedulerStatus stat;
2282 m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
2286 #if defined(RTS_SUPPORTS_THREADS)
2287 initCondition(&m->wakeup);
2290 /* see scheduleWaitThread() comment */
2291 ACQUIRE_LOCK(&sched_mutex);
2292 m->link = main_threads;
2295 IF_DEBUG(scheduler, sched_belch("waiting for thread %d", tso->id));
2296 #if defined(THREADED_RTS)
2297 stat = waitThread_(m, rtsFalse);
2299 stat = waitThread_(m);
2301 RELEASE_LOCK(&sched_mutex);
2307 waitThread_(StgMainThread* m
2308 #if defined(THREADED_RTS)
2309 , rtsBool blockWaiting
2313 SchedulerStatus stat;
2315 // Precondition: sched_mutex must be held.
2316 IF_DEBUG(scheduler, sched_belch("== scheduler: new main thread (%d)\n", m->tso->id));
2318 #if defined(RTS_SUPPORTS_THREADS)
2320 # if defined(THREADED_RTS)
2321 if (!blockWaiting) {
2322 /* In the threaded case, the OS thread that called main()
2323 * gets to enter the RTS directly without going via another
2326 main_main_thread = m;
2327 RELEASE_LOCK(&sched_mutex);
2329 ACQUIRE_LOCK(&sched_mutex);
2330 main_main_thread = NULL;
2331 ASSERT(m->stat != NoStatus);
2336 waitCondition(&m->wakeup, &sched_mutex);
2337 } while (m->stat == NoStatus);
2340 /* GranSim specific init */
2341 CurrentTSO = m->tso; // the TSO to run
2342 procStatus[MainProc] = Busy; // status of main PE
2343 CurrentProc = MainProc; // PE to run it on
2345 RELEASE_LOCK(&sched_mutex);
2348 RELEASE_LOCK(&sched_mutex);
2350 ASSERT(m->stat != NoStatus);
2355 #if defined(RTS_SUPPORTS_THREADS)
2356 closeCondition(&m->wakeup);
2359 IF_DEBUG(scheduler, fprintf(stderr, "== scheduler: main thread (%d) finished\n",
2363 // Postcondition: sched_mutex still held
2367 //@node Run queue code, Garbage Collextion Routines, Suspend and Resume, Main scheduling code
2368 //@subsection Run queue code
2372 NB: In GranSim we have many run queues; run_queue_hd is actually a macro
2373 unfolding to run_queue_hds[CurrentProc], thus CurrentProc is an
2374 implicit global variable that has to be correct when calling these
2378 /* Put the new thread on the head of the runnable queue.
2379 * The caller of createThread better push an appropriate closure
2380 * on this thread's stack before the scheduler is invoked.
2382 static /* inline */ void
2383 add_to_run_queue(tso)
2386 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
2387 tso->link = run_queue_hd;
2389 if (run_queue_tl == END_TSO_QUEUE) {
2394 /* Put the new thread at the end of the runnable queue. */
2395 static /* inline */ void
2396 push_on_run_queue(tso)
2399 ASSERT(get_itbl((StgClosure *)tso)->type == TSO);
2400 ASSERT(run_queue_hd!=NULL && run_queue_tl!=NULL);
2401 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
2402 if (run_queue_hd == END_TSO_QUEUE) {
2405 run_queue_tl->link = tso;
2411 Should be inlined because it's used very often in schedule. The tso
2412 argument is actually only needed in GranSim, where we want to have the
2413 possibility to schedule *any* TSO on the run queue, irrespective of the
2414 actual ordering. Therefore, if tso is not the nil TSO then we traverse
2415 the run queue and dequeue the tso, adjusting the links in the queue.
2417 //@cindex take_off_run_queue
2418 static /* inline */ StgTSO*
2419 take_off_run_queue(StgTSO *tso) {
2423 qetlaHbogh Qu' ngaSbogh ghomDaQ {tso} yIteq!
2425 if tso is specified, unlink that tso from the run_queue (doesn't have
2426 to be at the beginning of the queue); GranSim only
2428 if (tso!=END_TSO_QUEUE) {
2429 /* find tso in queue */
2430 for (t=run_queue_hd, prev=END_TSO_QUEUE;
2431 t!=END_TSO_QUEUE && t!=tso;
2435 /* now actually dequeue the tso */
2436 if (prev!=END_TSO_QUEUE) {
2437 ASSERT(run_queue_hd!=t);
2438 prev->link = t->link;
2440 /* t is at beginning of thread queue */
2441 ASSERT(run_queue_hd==t);
2442 run_queue_hd = t->link;
2444 /* t is at end of thread queue */
2445 if (t->link==END_TSO_QUEUE) {
2446 ASSERT(t==run_queue_tl);
2447 run_queue_tl = prev;
2449 ASSERT(run_queue_tl!=t);
2451 t->link = END_TSO_QUEUE;
2453 /* take tso from the beginning of the queue; std concurrent code */
2455 if (t != END_TSO_QUEUE) {
2456 run_queue_hd = t->link;
2457 t->link = END_TSO_QUEUE;
2458 if (run_queue_hd == END_TSO_QUEUE) {
2459 run_queue_tl = END_TSO_QUEUE;
2468 //@node Garbage Collextion Routines, Blocking Queue Routines, Run queue code, Main scheduling code
2469 //@subsection Garbage Collextion Routines
2471 /* ---------------------------------------------------------------------------
2472 Where are the roots that we know about?
2474 - all the threads on the runnable queue
2475 - all the threads on the blocked queue
2476 - all the threads on the sleeping queue
2477 - all the thread currently executing a _ccall_GC
2478 - all the "main threads"
2480 ------------------------------------------------------------------------ */
2482 /* This has to be protected either by the scheduler monitor, or by the
2483 garbage collection monitor (probably the latter).
2488 GetRoots(evac_fn evac)
2493 for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
2494 if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
2495 evac((StgClosure **)&run_queue_hds[i]);
2496 if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
2497 evac((StgClosure **)&run_queue_tls[i]);
2499 if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
2500 evac((StgClosure **)&blocked_queue_hds[i]);
2501 if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
2502 evac((StgClosure **)&blocked_queue_tls[i]);
2503 if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
2504 evac((StgClosure **)&ccalling_threads[i]);
2511 if (run_queue_hd != END_TSO_QUEUE) {
2512 ASSERT(run_queue_tl != END_TSO_QUEUE);
2513 evac((StgClosure **)&run_queue_hd);
2514 evac((StgClosure **)&run_queue_tl);
2517 if (blocked_queue_hd != END_TSO_QUEUE) {
2518 ASSERT(blocked_queue_tl != END_TSO_QUEUE);
2519 evac((StgClosure **)&blocked_queue_hd);
2520 evac((StgClosure **)&blocked_queue_tl);
2523 if (sleeping_queue != END_TSO_QUEUE) {
2524 evac((StgClosure **)&sleeping_queue);
2528 if (suspended_ccalling_threads != END_TSO_QUEUE) {
2529 evac((StgClosure **)&suspended_ccalling_threads);
2532 #if defined(PAR) || defined(GRAN)
2533 markSparkQueue(evac);
2536 #if defined(RTS_USER_SIGNALS)
2537 // mark the signal handlers (signals should be already blocked)
2538 markSignalHandlers(evac);
2541 // main threads which have completed need to be retained until they
2542 // are dealt with in the main scheduler loop. They won't be
2543 // retained any other way: the GC will drop them from the
2544 // all_threads list, so we have to be careful to treat them as roots
2548 for (m = main_threads; m != NULL; m = m->link) {
2549 switch (m->tso->what_next) {
2550 case ThreadComplete:
2552 evac((StgClosure **)&m->tso);
2561 /* -----------------------------------------------------------------------------
2564 This is the interface to the garbage collector from Haskell land.
2565 We provide this so that external C code can allocate and garbage
2566 collect when called from Haskell via _ccall_GC.
2568 It might be useful to provide an interface whereby the programmer
2569 can specify more roots (ToDo).
2571 This needs to be protected by the GC condition variable above. KH.
2572 -------------------------------------------------------------------------- */
2574 static void (*extra_roots)(evac_fn);
2579 /* Obligated to hold this lock upon entry */
2580 ACQUIRE_LOCK(&sched_mutex);
2581 GarbageCollect(GetRoots,rtsFalse);
2582 RELEASE_LOCK(&sched_mutex);
2586 performMajorGC(void)
2588 ACQUIRE_LOCK(&sched_mutex);
2589 GarbageCollect(GetRoots,rtsTrue);
2590 RELEASE_LOCK(&sched_mutex);
2594 AllRoots(evac_fn evac)
2596 GetRoots(evac); // the scheduler's roots
2597 extra_roots(evac); // the user's roots
2601 performGCWithRoots(void (*get_roots)(evac_fn))
2603 ACQUIRE_LOCK(&sched_mutex);
2604 extra_roots = get_roots;
2605 GarbageCollect(AllRoots,rtsFalse);
2606 RELEASE_LOCK(&sched_mutex);
2609 /* -----------------------------------------------------------------------------
2612 If the thread has reached its maximum stack size, then raise the
2613 StackOverflow exception in the offending thread. Otherwise
2614 relocate the TSO into a larger chunk of memory and adjust its stack
2616 -------------------------------------------------------------------------- */
2619 threadStackOverflow(StgTSO *tso)
2621 nat new_stack_size, new_tso_size, stack_words;
2625 IF_DEBUG(sanity,checkTSO(tso));
2626 if (tso->stack_size >= tso->max_stack_size) {
2629 belch("@@ threadStackOverflow of TSO %d (%p): stack too large (now %ld; max is %ld",
2630 tso->id, tso, tso->stack_size, tso->max_stack_size);
2631 /* If we're debugging, just print out the top of the stack */
2632 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2635 /* Send this thread the StackOverflow exception */
2636 raiseAsync(tso, (StgClosure *)stackOverflow_closure);
2640 /* Try to double the current stack size. If that takes us over the
2641 * maximum stack size for this thread, then use the maximum instead.
2642 * Finally round up so the TSO ends up as a whole number of blocks.
2644 new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
2645 new_tso_size = (nat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
2646 TSO_STRUCT_SIZE)/sizeof(W_);
2647 new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
2648 new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
2650 IF_DEBUG(scheduler, fprintf(stderr,"== scheduler: increasing stack size from %d words to %d.\n", tso->stack_size, new_stack_size));
2652 dest = (StgTSO *)allocate(new_tso_size);
2653 TICK_ALLOC_TSO(new_stack_size,0);
2655 /* copy the TSO block and the old stack into the new area */
2656 memcpy(dest,tso,TSO_STRUCT_SIZE);
2657 stack_words = tso->stack + tso->stack_size - tso->sp;
2658 new_sp = (P_)dest + new_tso_size - stack_words;
2659 memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
2661 /* relocate the stack pointers... */
2663 dest->stack_size = new_stack_size;
2665 /* Mark the old TSO as relocated. We have to check for relocated
2666 * TSOs in the garbage collector and any primops that deal with TSOs.
2668 * It's important to set the sp value to just beyond the end
2669 * of the stack, so we don't attempt to scavenge any part of the
2672 tso->what_next = ThreadRelocated;
2674 tso->sp = (P_)&(tso->stack[tso->stack_size]);
2675 tso->why_blocked = NotBlocked;
2676 dest->mut_link = NULL;
2678 IF_PAR_DEBUG(verbose,
2679 belch("@@ threadStackOverflow of TSO %d (now at %p): stack size increased to %ld",
2680 tso->id, tso, tso->stack_size);
2681 /* If we're debugging, just print out the top of the stack */
2682 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2685 IF_DEBUG(sanity,checkTSO(tso));
2687 IF_DEBUG(scheduler,printTSO(dest));
2693 //@node Blocking Queue Routines, Exception Handling Routines, Garbage Collextion Routines, Main scheduling code
2694 //@subsection Blocking Queue Routines
2696 /* ---------------------------------------------------------------------------
2697 Wake up a queue that was blocked on some resource.
2698 ------------------------------------------------------------------------ */
2702 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2707 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2709 /* write RESUME events to log file and
2710 update blocked and fetch time (depending on type of the orig closure) */
2711 if (RtsFlags.ParFlags.ParStats.Full) {
2712 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
2713 GR_RESUMEQ, ((StgTSO *)bqe), ((StgTSO *)bqe)->block_info.closure,
2714 0, 0 /* spark_queue_len(ADVISORY_POOL) */);
2715 if (EMPTY_RUN_QUEUE())
2716 emitSchedule = rtsTrue;
2718 switch (get_itbl(node)->type) {
2720 ((StgTSO *)bqe)->par.fetchtime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2725 ((StgTSO *)bqe)->par.blocktime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2732 barf("{unblockOneLocked}Daq Qagh: unexpected closure in blocking queue");
2739 static StgBlockingQueueElement *
2740 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2743 PEs node_loc, tso_loc;
2745 node_loc = where_is(node); // should be lifted out of loop
2746 tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2747 tso_loc = where_is((StgClosure *)tso);
2748 if (IS_LOCAL_TO(PROCS(node),tso_loc)) { // TSO is local
2749 /* !fake_fetch => TSO is on CurrentProc is same as IS_LOCAL_TO */
2750 ASSERT(CurrentProc!=node_loc || tso_loc==CurrentProc);
2751 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.lunblocktime;
2752 // insertThread(tso, node_loc);
2753 new_event(tso_loc, tso_loc, CurrentTime[CurrentProc],
2755 tso, node, (rtsSpark*)NULL);
2756 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2759 } else { // TSO is remote (actually should be FMBQ)
2760 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.mpacktime +
2761 RtsFlags.GranFlags.Costs.gunblocktime +
2762 RtsFlags.GranFlags.Costs.latency;
2763 new_event(tso_loc, CurrentProc, CurrentTime[CurrentProc],
2765 tso, node, (rtsSpark*)NULL);
2766 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2769 /* the thread-queue-overhead is accounted for in either Resume or UnblockThread */
2771 fprintf(stderr," %s TSO %d (%p) [PE %d] (block_info.closure=%p) (next=%p) ,",
2772 (node_loc==tso_loc ? "Local" : "Global"),
2773 tso->id, tso, CurrentProc, tso->block_info.closure, tso->link));
2774 tso->block_info.closure = NULL;
2775 IF_DEBUG(scheduler,belch("-- Waking up thread %ld (%p)",
2779 static StgBlockingQueueElement *
2780 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2782 StgBlockingQueueElement *next;
2784 switch (get_itbl(bqe)->type) {
2786 ASSERT(((StgTSO *)bqe)->why_blocked != NotBlocked);
2787 /* if it's a TSO just push it onto the run_queue */
2789 // ((StgTSO *)bqe)->link = END_TSO_QUEUE; // debugging?
2790 PUSH_ON_RUN_QUEUE((StgTSO *)bqe);
2792 unblockCount(bqe, node);
2793 /* reset blocking status after dumping event */
2794 ((StgTSO *)bqe)->why_blocked = NotBlocked;
2798 /* if it's a BLOCKED_FETCH put it on the PendingFetches list */
2800 bqe->link = (StgBlockingQueueElement *)PendingFetches;
2801 PendingFetches = (StgBlockedFetch *)bqe;
2805 /* can ignore this case in a non-debugging setup;
2806 see comments on RBHSave closures above */
2808 /* check that the closure is an RBHSave closure */
2809 ASSERT(get_itbl((StgClosure *)bqe) == &stg_RBH_Save_0_info ||
2810 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_1_info ||
2811 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_2_info);
2815 barf("{unblockOneLocked}Daq Qagh: Unexpected IP (%#lx; %s) in blocking queue at %#lx\n",
2816 get_itbl((StgClosure *)bqe), info_type((StgClosure *)bqe),
2820 IF_PAR_DEBUG(bq, fprintf(stderr, ", %p (%s)", bqe, info_type((StgClosure*)bqe)));
2824 #else /* !GRAN && !PAR */
2826 unblockOneLocked(StgTSO *tso)
2830 ASSERT(get_itbl(tso)->type == TSO);
2831 ASSERT(tso->why_blocked != NotBlocked);
2832 tso->why_blocked = NotBlocked;
2834 PUSH_ON_RUN_QUEUE(tso);
2836 IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
2841 #if defined(GRAN) || defined(PAR)
2842 inline StgBlockingQueueElement *
2843 unblockOne(StgBlockingQueueElement *bqe, StgClosure *node)
2845 ACQUIRE_LOCK(&sched_mutex);
2846 bqe = unblockOneLocked(bqe, node);
2847 RELEASE_LOCK(&sched_mutex);
2852 unblockOne(StgTSO *tso)
2854 ACQUIRE_LOCK(&sched_mutex);
2855 tso = unblockOneLocked(tso);
2856 RELEASE_LOCK(&sched_mutex);
2863 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2865 StgBlockingQueueElement *bqe;
2870 belch("##-_ AwBQ for node %p on PE %d @ %ld by TSO %d (%p): ", \
2871 node, CurrentProc, CurrentTime[CurrentProc],
2872 CurrentTSO->id, CurrentTSO));
2874 node_loc = where_is(node);
2876 ASSERT(q == END_BQ_QUEUE ||
2877 get_itbl(q)->type == TSO || // q is either a TSO or an RBHSave
2878 get_itbl(q)->type == CONSTR); // closure (type constructor)
2879 ASSERT(is_unique(node));
2881 /* FAKE FETCH: magically copy the node to the tso's proc;
2882 no Fetch necessary because in reality the node should not have been
2883 moved to the other PE in the first place
2885 if (CurrentProc!=node_loc) {
2887 belch("## node %p is on PE %d but CurrentProc is %d (TSO %d); assuming fake fetch and adjusting bitmask (old: %#x)",
2888 node, node_loc, CurrentProc, CurrentTSO->id,
2889 // CurrentTSO, where_is(CurrentTSO),
2890 node->header.gran.procs));
2891 node->header.gran.procs = (node->header.gran.procs) | PE_NUMBER(CurrentProc);
2893 belch("## new bitmask of node %p is %#x",
2894 node, node->header.gran.procs));
2895 if (RtsFlags.GranFlags.GranSimStats.Global) {
2896 globalGranStats.tot_fake_fetches++;
2901 // ToDo: check: ASSERT(CurrentProc==node_loc);
2902 while (get_itbl(bqe)->type==TSO) { // q != END_TSO_QUEUE) {
2905 bqe points to the current element in the queue
2906 next points to the next element in the queue
2908 //tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2909 //tso_loc = where_is(tso);
2911 bqe = unblockOneLocked(bqe, node);
2914 /* if this is the BQ of an RBH, we have to put back the info ripped out of
2915 the closure to make room for the anchor of the BQ */
2916 if (bqe!=END_BQ_QUEUE) {
2917 ASSERT(get_itbl(node)->type == RBH && get_itbl(bqe)->type == CONSTR);
2919 ASSERT((info_ptr==&RBH_Save_0_info) ||
2920 (info_ptr==&RBH_Save_1_info) ||
2921 (info_ptr==&RBH_Save_2_info));
2923 /* cf. convertToRBH in RBH.c for writing the RBHSave closure */
2924 ((StgRBH *)node)->blocking_queue = (StgBlockingQueueElement *)((StgRBHSave *)bqe)->payload[0];
2925 ((StgRBH *)node)->mut_link = (StgMutClosure *)((StgRBHSave *)bqe)->payload[1];
2928 belch("## Filled in RBH_Save for %p (%s) at end of AwBQ",
2929 node, info_type(node)));
2932 /* statistics gathering */
2933 if (RtsFlags.GranFlags.GranSimStats.Global) {
2934 // globalGranStats.tot_bq_processing_time += bq_processing_time;
2935 globalGranStats.tot_bq_len += len; // total length of all bqs awakened
2936 // globalGranStats.tot_bq_len_local += len_local; // same for local TSOs only
2937 globalGranStats.tot_awbq++; // total no. of bqs awakened
2940 fprintf(stderr,"## BQ Stats of %p: [%d entries] %s\n",
2941 node, len, (bqe!=END_BQ_QUEUE) ? "RBH" : ""));
2945 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2947 StgBlockingQueueElement *bqe;
2949 ACQUIRE_LOCK(&sched_mutex);
2951 IF_PAR_DEBUG(verbose,
2952 belch("##-_ AwBQ for node %p on [%x]: ",
2956 if(get_itbl(q)->type == CONSTR || q==END_BQ_QUEUE) {
2957 IF_PAR_DEBUG(verbose, belch("## ... nothing to unblock so lets just return. RFP (BUG?)"));
2962 ASSERT(q == END_BQ_QUEUE ||
2963 get_itbl(q)->type == TSO ||
2964 get_itbl(q)->type == BLOCKED_FETCH ||
2965 get_itbl(q)->type == CONSTR);
2968 while (get_itbl(bqe)->type==TSO ||
2969 get_itbl(bqe)->type==BLOCKED_FETCH) {
2970 bqe = unblockOneLocked(bqe, node);
2972 RELEASE_LOCK(&sched_mutex);
2975 #else /* !GRAN && !PAR */
2977 #ifdef RTS_SUPPORTS_THREADS
2979 awakenBlockedQueueNoLock(StgTSO *tso)
2981 while (tso != END_TSO_QUEUE) {
2982 tso = unblockOneLocked(tso);
2988 awakenBlockedQueue(StgTSO *tso)
2990 ACQUIRE_LOCK(&sched_mutex);
2991 while (tso != END_TSO_QUEUE) {
2992 tso = unblockOneLocked(tso);
2994 RELEASE_LOCK(&sched_mutex);
2998 //@node Exception Handling Routines, Debugging Routines, Blocking Queue Routines, Main scheduling code
2999 //@subsection Exception Handling Routines
3001 /* ---------------------------------------------------------------------------
3003 - usually called inside a signal handler so it mustn't do anything fancy.
3004 ------------------------------------------------------------------------ */
3007 interruptStgRts(void)
3013 /* -----------------------------------------------------------------------------
3016 This is for use when we raise an exception in another thread, which
3018 This has nothing to do with the UnblockThread event in GranSim. -- HWL
3019 -------------------------------------------------------------------------- */
3021 #if defined(GRAN) || defined(PAR)
3023 NB: only the type of the blocking queue is different in GranSim and GUM
3024 the operations on the queue-elements are the same
3025 long live polymorphism!
3027 Locks: sched_mutex is held upon entry and exit.
3031 unblockThread(StgTSO *tso)
3033 StgBlockingQueueElement *t, **last;
3035 switch (tso->why_blocked) {
3038 return; /* not blocked */
3041 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
3043 StgBlockingQueueElement *last_tso = END_BQ_QUEUE;
3044 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
3046 last = (StgBlockingQueueElement **)&mvar->head;
3047 for (t = (StgBlockingQueueElement *)mvar->head;
3049 last = &t->link, last_tso = t, t = t->link) {
3050 if (t == (StgBlockingQueueElement *)tso) {
3051 *last = (StgBlockingQueueElement *)tso->link;
3052 if (mvar->tail == tso) {
3053 mvar->tail = (StgTSO *)last_tso;
3058 barf("unblockThread (MVAR): TSO not found");
3061 case BlockedOnBlackHole:
3062 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
3064 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
3066 last = &bq->blocking_queue;
3067 for (t = bq->blocking_queue;
3069 last = &t->link, t = t->link) {
3070 if (t == (StgBlockingQueueElement *)tso) {
3071 *last = (StgBlockingQueueElement *)tso->link;
3075 barf("unblockThread (BLACKHOLE): TSO not found");
3078 case BlockedOnException:
3080 StgTSO *target = tso->block_info.tso;
3082 ASSERT(get_itbl(target)->type == TSO);
3084 if (target->what_next == ThreadRelocated) {
3085 target = target->link;
3086 ASSERT(get_itbl(target)->type == TSO);
3089 ASSERT(target->blocked_exceptions != NULL);
3091 last = (StgBlockingQueueElement **)&target->blocked_exceptions;
3092 for (t = (StgBlockingQueueElement *)target->blocked_exceptions;
3094 last = &t->link, t = t->link) {
3095 ASSERT(get_itbl(t)->type == TSO);
3096 if (t == (StgBlockingQueueElement *)tso) {
3097 *last = (StgBlockingQueueElement *)tso->link;
3101 barf("unblockThread (Exception): TSO not found");
3105 case BlockedOnWrite:
3106 #if defined(mingw32_TARGET_OS)
3107 case BlockedOnDoProc:
3110 /* take TSO off blocked_queue */
3111 StgBlockingQueueElement *prev = NULL;
3112 for (t = (StgBlockingQueueElement *)blocked_queue_hd; t != END_BQ_QUEUE;
3113 prev = t, t = t->link) {
3114 if (t == (StgBlockingQueueElement *)tso) {
3116 blocked_queue_hd = (StgTSO *)t->link;
3117 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
3118 blocked_queue_tl = END_TSO_QUEUE;
3121 prev->link = t->link;
3122 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
3123 blocked_queue_tl = (StgTSO *)prev;
3129 barf("unblockThread (I/O): TSO not found");
3132 case BlockedOnDelay:
3134 /* take TSO off sleeping_queue */
3135 StgBlockingQueueElement *prev = NULL;
3136 for (t = (StgBlockingQueueElement *)sleeping_queue; t != END_BQ_QUEUE;
3137 prev = t, t = t->link) {
3138 if (t == (StgBlockingQueueElement *)tso) {
3140 sleeping_queue = (StgTSO *)t->link;
3142 prev->link = t->link;
3147 barf("unblockThread (delay): TSO not found");
3151 barf("unblockThread");
3155 tso->link = END_TSO_QUEUE;
3156 tso->why_blocked = NotBlocked;
3157 tso->block_info.closure = NULL;
3158 PUSH_ON_RUN_QUEUE(tso);
3162 unblockThread(StgTSO *tso)
3166 /* To avoid locking unnecessarily. */
3167 if (tso->why_blocked == NotBlocked) {
3171 switch (tso->why_blocked) {
3174 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
3176 StgTSO *last_tso = END_TSO_QUEUE;
3177 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
3180 for (t = mvar->head; t != END_TSO_QUEUE;
3181 last = &t->link, last_tso = t, t = t->link) {
3184 if (mvar->tail == tso) {
3185 mvar->tail = last_tso;
3190 barf("unblockThread (MVAR): TSO not found");
3193 case BlockedOnBlackHole:
3194 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
3196 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
3198 last = &bq->blocking_queue;
3199 for (t = bq->blocking_queue; t != END_TSO_QUEUE;
3200 last = &t->link, t = t->link) {
3206 barf("unblockThread (BLACKHOLE): TSO not found");
3209 case BlockedOnException:
3211 StgTSO *target = tso->block_info.tso;
3213 ASSERT(get_itbl(target)->type == TSO);
3215 while (target->what_next == ThreadRelocated) {
3216 target = target->link;
3217 ASSERT(get_itbl(target)->type == TSO);
3220 ASSERT(target->blocked_exceptions != NULL);
3222 last = &target->blocked_exceptions;
3223 for (t = target->blocked_exceptions; t != END_TSO_QUEUE;
3224 last = &t->link, t = t->link) {
3225 ASSERT(get_itbl(t)->type == TSO);
3231 barf("unblockThread (Exception): TSO not found");
3235 case BlockedOnWrite:
3236 #if defined(mingw32_TARGET_OS)
3237 case BlockedOnDoProc:
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 (delay): 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 #if defined(mingw32_TARGET_OS)
3633 case BlockedOnDoProc:
3634 fprintf(stderr,"is blocked on proc (request: %d)", tso->block_info.async_result->reqID);
3637 case BlockedOnDelay:
3638 fprintf(stderr,"is blocked until %d", tso->block_info.target);
3641 fprintf(stderr,"is blocked on an MVar");
3643 case BlockedOnException:
3644 fprintf(stderr,"is blocked on delivering an exception to thread %d",
3645 tso->block_info.tso->id);
3647 case BlockedOnBlackHole:
3648 fprintf(stderr,"is blocked on a black hole");
3651 fprintf(stderr,"is not blocked");
3655 fprintf(stderr,"is blocked on global address; local FM_BQ is %p (%s)",
3656 tso->block_info.closure, info_type(tso->block_info.closure));
3658 case BlockedOnGA_NoSend:
3659 fprintf(stderr,"is blocked on global address (no send); local FM_BQ is %p (%s)",
3660 tso->block_info.closure, info_type(tso->block_info.closure));
3663 #if defined(RTS_SUPPORTS_THREADS)
3664 case BlockedOnCCall:
3665 fprintf(stderr,"is blocked on an external call");
3667 case BlockedOnCCall_NoUnblockExc:
3668 fprintf(stderr,"is blocked on an external call (exceptions were already blocked)");
3672 barf("printThreadBlockage: strange tso->why_blocked: %d for TSO %d (%d)",
3673 tso->why_blocked, tso->id, tso);
3679 printThreadStatus(StgTSO *tso)
3681 switch (tso->what_next) {
3683 fprintf(stderr,"has been killed");
3685 case ThreadComplete:
3686 fprintf(stderr,"has completed");
3689 printThreadBlockage(tso);
3694 printAllThreads(void)
3700 char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN];
3701 ullong_format_string(TIME_ON_PROC(CurrentProc),
3702 time_string, rtsFalse/*no commas!*/);
3704 fprintf(stderr, "all threads at [%s]:\n", time_string);
3706 char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN];
3707 ullong_format_string(CURRENT_TIME,
3708 time_string, rtsFalse/*no commas!*/);
3710 fprintf(stderr,"all threads at [%s]:\n", time_string);
3712 fprintf(stderr,"all threads:\n");
3715 for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
3716 fprintf(stderr, "\tthread %d @ %p ", t->id, (void *)t);
3717 label = lookupThreadLabel((StgWord)t);
3718 if (label) fprintf(stderr,"[\"%s\"] ",(char *)label);
3719 printThreadStatus(t);
3720 fprintf(stderr,"\n");
3727 Print a whole blocking queue attached to node (debugging only).
3732 print_bq (StgClosure *node)
3734 StgBlockingQueueElement *bqe;
3738 fprintf(stderr,"## BQ of closure %p (%s): ",
3739 node, info_type(node));
3741 /* should cover all closures that may have a blocking queue */
3742 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3743 get_itbl(node)->type == FETCH_ME_BQ ||
3744 get_itbl(node)->type == RBH ||
3745 get_itbl(node)->type == MVAR);
3747 ASSERT(node!=(StgClosure*)NULL); // sanity check
3749 print_bqe(((StgBlockingQueue*)node)->blocking_queue);
3753 Print a whole blocking queue starting with the element bqe.
3756 print_bqe (StgBlockingQueueElement *bqe)
3761 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3763 for (end = (bqe==END_BQ_QUEUE);
3764 !end; // iterate until bqe points to a CONSTR
3765 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE),
3766 bqe = end ? END_BQ_QUEUE : bqe->link) {
3767 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3768 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
3769 /* types of closures that may appear in a blocking queue */
3770 ASSERT(get_itbl(bqe)->type == TSO ||
3771 get_itbl(bqe)->type == BLOCKED_FETCH ||
3772 get_itbl(bqe)->type == CONSTR);
3773 /* only BQs of an RBH end with an RBH_Save closure */
3774 //ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3776 switch (get_itbl(bqe)->type) {
3778 fprintf(stderr," TSO %u (%x),",
3779 ((StgTSO *)bqe)->id, ((StgTSO *)bqe));
3782 fprintf(stderr," BF (node=%p, ga=((%x, %d, %x)),",
3783 ((StgBlockedFetch *)bqe)->node,
3784 ((StgBlockedFetch *)bqe)->ga.payload.gc.gtid,
3785 ((StgBlockedFetch *)bqe)->ga.payload.gc.slot,
3786 ((StgBlockedFetch *)bqe)->ga.weight);
3789 fprintf(stderr," %s (IP %p),",
3790 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3791 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3792 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3793 "RBH_Save_?"), get_itbl(bqe));
3796 barf("Unexpected closure type %s in blocking queue", // of %p (%s)",
3797 info_type((StgClosure *)bqe)); // , node, info_type(node));
3801 fputc('\n', stderr);
3803 # elif defined(GRAN)
3805 print_bq (StgClosure *node)
3807 StgBlockingQueueElement *bqe;
3808 PEs node_loc, tso_loc;
3811 /* should cover all closures that may have a blocking queue */
3812 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3813 get_itbl(node)->type == FETCH_ME_BQ ||
3814 get_itbl(node)->type == RBH);
3816 ASSERT(node!=(StgClosure*)NULL); // sanity check
3817 node_loc = where_is(node);
3819 fprintf(stderr,"## BQ of closure %p (%s) on [PE %d]: ",
3820 node, info_type(node), node_loc);
3823 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3825 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
3826 !end; // iterate until bqe points to a CONSTR
3827 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
3828 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3829 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
3830 /* types of closures that may appear in a blocking queue */
3831 ASSERT(get_itbl(bqe)->type == TSO ||
3832 get_itbl(bqe)->type == CONSTR);
3833 /* only BQs of an RBH end with an RBH_Save closure */
3834 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3836 tso_loc = where_is((StgClosure *)bqe);
3837 switch (get_itbl(bqe)->type) {
3839 fprintf(stderr," TSO %d (%p) on [PE %d],",
3840 ((StgTSO *)bqe)->id, (StgTSO *)bqe, tso_loc);
3843 fprintf(stderr," %s (IP %p),",
3844 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3845 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3846 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3847 "RBH_Save_?"), get_itbl(bqe));
3850 barf("Unexpected closure type %s in blocking queue of %p (%s)",
3851 info_type((StgClosure *)bqe), node, info_type(node));
3855 fputc('\n', stderr);
3859 Nice and easy: only TSOs on the blocking queue
3862 print_bq (StgClosure *node)
3866 ASSERT(node!=(StgClosure*)NULL); // sanity check
3867 for (tso = ((StgBlockingQueue*)node)->blocking_queue;
3868 tso != END_TSO_QUEUE;
3870 ASSERT(tso!=NULL && tso!=END_TSO_QUEUE); // sanity check
3871 ASSERT(get_itbl(tso)->type == TSO); // guess what, sanity check
3872 fprintf(stderr," TSO %d (%p),", tso->id, tso);
3874 fputc('\n', stderr);
3885 for (i=0, tso=run_queue_hd;
3886 tso != END_TSO_QUEUE;
3895 sched_belch(char *s, ...)
3900 fprintf(stderr, "scheduler (task %ld): ", osThreadId());
3902 fprintf(stderr, "== ");
3904 fprintf(stderr, "scheduler: ");
3906 vfprintf(stderr, s, ap);
3907 fprintf(stderr, "\n");
3914 //@node Index, , Debugging Routines, Main scheduling code
3918 //* StgMainThread:: @cindex\s-+StgMainThread
3919 //* awaken_blocked_queue:: @cindex\s-+awaken_blocked_queue
3920 //* blocked_queue_hd:: @cindex\s-+blocked_queue_hd
3921 //* blocked_queue_tl:: @cindex\s-+blocked_queue_tl
3922 //* context_switch:: @cindex\s-+context_switch
3923 //* createThread:: @cindex\s-+createThread
3924 //* gc_pending_cond:: @cindex\s-+gc_pending_cond
3925 //* initScheduler:: @cindex\s-+initScheduler
3926 //* interrupted:: @cindex\s-+interrupted
3927 //* next_thread_id:: @cindex\s-+next_thread_id
3928 //* print_bq:: @cindex\s-+print_bq
3929 //* run_queue_hd:: @cindex\s-+run_queue_hd
3930 //* run_queue_tl:: @cindex\s-+run_queue_tl
3931 //* sched_mutex:: @cindex\s-+sched_mutex
3932 //* schedule:: @cindex\s-+schedule
3933 //* take_off_run_queue:: @cindex\s-+take_off_run_queue
3934 //* term_mutex:: @cindex\s-+term_mutex