1 /* ---------------------------------------------------------------------------
2 * $Id: Schedule.c,v 1.87 2001/01/24 15:46:19 simonmar Exp $
4 * (c) The GHC Team, 1998-2000
8 * The main scheduling code in GranSim is quite different from that in std
9 * (concurrent) Haskell: while concurrent Haskell just iterates over the
10 * threads in the runnable queue, GranSim is event driven, i.e. it iterates
11 * over the events in the global event queue. -- HWL
12 * --------------------------------------------------------------------------*/
14 //@node Main scheduling code, , ,
15 //@section Main scheduling code
17 /* Version with scheduler monitor support for SMPs.
19 This design provides a high-level API to create and schedule threads etc.
20 as documented in the SMP design document.
22 It uses a monitor design controlled by a single mutex to exercise control
23 over accesses to shared data structures, and builds on the Posix threads
26 The majority of state is shared. In order to keep essential per-task state,
27 there is a Capability structure, which contains all the information
28 needed to run a thread: its STG registers, a pointer to its TSO, a
29 nursery etc. During STG execution, a pointer to the capability is
30 kept in a register (BaseReg).
32 In a non-SMP build, there is one global capability, namely MainRegTable.
39 //* Variables and Data structures::
40 //* Main scheduling loop::
41 //* Suspend and Resume::
43 //* Garbage Collextion Routines::
44 //* Blocking Queue Routines::
45 //* Exception Handling Routines::
46 //* Debugging Routines::
50 //@node Includes, Variables and Data structures, Main scheduling code, Main scheduling code
51 //@subsection Includes
59 #include "StgStartup.h"
63 #include "StgMiscClosures.h"
65 #include "Interpreter.h"
66 #include "Exception.h"
74 #if defined(GRAN) || defined(PAR)
75 # include "GranSimRts.h"
77 # include "ParallelRts.h"
78 # include "Parallel.h"
79 # include "ParallelDebug.h"
87 //@node Variables and Data structures, Prototypes, Includes, Main scheduling code
88 //@subsection Variables and Data structures
92 * These are the threads which clients have requested that we run.
94 * In an SMP build, we might have several concurrent clients all
95 * waiting for results, and each one will wait on a condition variable
96 * until the result is available.
98 * In non-SMP, clients are strictly nested: the first client calls
99 * into the RTS, which might call out again to C with a _ccall_GC, and
100 * eventually re-enter the RTS.
102 * Main threads information is kept in a linked list:
104 //@cindex StgMainThread
105 typedef struct StgMainThread_ {
107 SchedulerStatus stat;
110 pthread_cond_t wakeup;
112 struct StgMainThread_ *link;
115 /* Main thread queue.
116 * Locks required: sched_mutex.
118 static StgMainThread *main_threads;
121 * Locks required: sched_mutex.
125 StgTSO* ActiveTSO = NULL; /* for assigning system costs; GranSim-Light only */
126 /* rtsTime TimeOfNextEvent, EndOfTimeSlice; now in GranSim.c */
129 In GranSim we have a runable and a blocked queue for each processor.
130 In order to minimise code changes new arrays run_queue_hds/tls
131 are created. run_queue_hd is then a short cut (macro) for
132 run_queue_hds[CurrentProc] (see GranSim.h).
135 StgTSO *run_queue_hds[MAX_PROC], *run_queue_tls[MAX_PROC];
136 StgTSO *blocked_queue_hds[MAX_PROC], *blocked_queue_tls[MAX_PROC];
137 StgTSO *ccalling_threadss[MAX_PROC];
138 /* We use the same global list of threads (all_threads) in GranSim as in
139 the std RTS (i.e. we are cheating). However, we don't use this list in
140 the GranSim specific code at the moment (so we are only potentially
145 StgTSO *run_queue_hd, *run_queue_tl;
146 StgTSO *blocked_queue_hd, *blocked_queue_tl;
147 StgTSO *sleeping_queue; /* perhaps replace with a hash table? */
151 /* Linked list of all threads.
152 * Used for detecting garbage collected threads.
156 /* Threads suspended in _ccall_GC.
158 static StgTSO *suspended_ccalling_threads;
160 static void GetRoots(void);
161 static StgTSO *threadStackOverflow(StgTSO *tso);
163 /* KH: The following two flags are shared memory locations. There is no need
164 to lock them, since they are only unset at the end of a scheduler
168 /* flag set by signal handler to precipitate a context switch */
169 //@cindex context_switch
172 /* if this flag is set as well, give up execution */
173 //@cindex interrupted
176 /* Next thread ID to allocate.
177 * Locks required: sched_mutex
179 //@cindex next_thread_id
180 StgThreadID next_thread_id = 1;
183 * Pointers to the state of the current thread.
184 * Rule of thumb: if CurrentTSO != NULL, then we're running a Haskell
185 * thread. If CurrentTSO == NULL, then we're at the scheduler level.
188 /* The smallest stack size that makes any sense is:
189 * RESERVED_STACK_WORDS (so we can get back from the stack overflow)
190 * + sizeofW(StgStopFrame) (the stg_stop_thread_info frame)
191 * + 1 (the realworld token for an IO thread)
192 * + 1 (the closure to enter)
194 * A thread with this stack will bomb immediately with a stack
195 * overflow, which will increase its stack size.
198 #define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 2)
200 /* Free capability list.
201 * Locks required: sched_mutex.
204 //@cindex free_capabilities
205 //@cindex n_free_capabilities
206 Capability *free_capabilities; /* Available capabilities for running threads */
207 nat n_free_capabilities; /* total number of available capabilities */
209 //@cindex MainRegTable
210 Capability MainRegTable; /* for non-SMP, we have one global capability */
217 /* This is used in `TSO.h' and gcc 2.96 insists that this variable actually
218 * exists - earlier gccs apparently didn't.
225 /* All our current task ids, saved in case we need to kill them later.
232 void addToBlockedQueue ( StgTSO *tso );
234 static void schedule ( void );
235 void interruptStgRts ( void );
237 static StgTSO * createThread_ ( nat size, rtsBool have_lock, StgInt pri );
239 static StgTSO * createThread_ ( nat size, rtsBool have_lock );
242 static void detectBlackHoles ( void );
245 static void sched_belch(char *s, ...);
249 //@cindex sched_mutex
251 //@cindex thread_ready_cond
252 //@cindex gc_pending_cond
253 pthread_mutex_t sched_mutex = PTHREAD_MUTEX_INITIALIZER;
254 pthread_mutex_t term_mutex = PTHREAD_MUTEX_INITIALIZER;
255 pthread_cond_t thread_ready_cond = PTHREAD_COND_INITIALIZER;
256 pthread_cond_t gc_pending_cond = PTHREAD_COND_INITIALIZER;
263 rtsTime TimeOfLastYield;
267 char *whatNext_strs[] = {
275 char *threadReturnCode_strs[] = {
276 "HeapOverflow", /* might also be StackOverflow */
285 * The thread state for the main thread.
286 // ToDo: check whether not needed any more
290 //@node Main scheduling loop, Suspend and Resume, Prototypes, Main scheduling code
291 //@subsection Main scheduling loop
293 /* ---------------------------------------------------------------------------
294 Main scheduling loop.
296 We use round-robin scheduling, each thread returning to the
297 scheduler loop when one of these conditions is detected:
300 * timer expires (thread yields)
305 Locking notes: we acquire the scheduler lock once at the beginning
306 of the scheduler loop, and release it when
308 * running a thread, or
309 * waiting for work, or
310 * waiting for a GC to complete.
313 In a GranSim setup this loop iterates over the global event queue.
314 This revolves around the global event queue, which determines what
315 to do next. Therefore, it's more complicated than either the
316 concurrent or the parallel (GUM) setup.
319 GUM iterates over incoming messages.
320 It starts with nothing to do (thus CurrentTSO == END_TSO_QUEUE),
321 and sends out a fish whenever it has nothing to do; in-between
322 doing the actual reductions (shared code below) it processes the
323 incoming messages and deals with delayed operations
324 (see PendingFetches).
325 This is not the ugliest code you could imagine, but it's bloody close.
327 ------------------------------------------------------------------------ */
334 StgThreadReturnCode ret;
343 rtsBool was_interrupted = rtsFalse;
345 ACQUIRE_LOCK(&sched_mutex);
349 /* set up first event to get things going */
350 /* ToDo: assign costs for system setup and init MainTSO ! */
351 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
353 CurrentTSO, (StgClosure*)NULL, (rtsSpark*)NULL);
356 fprintf(stderr, "GRAN: Init CurrentTSO (in schedule) = %p\n", CurrentTSO);
357 G_TSO(CurrentTSO, 5));
359 if (RtsFlags.GranFlags.Light) {
360 /* Save current time; GranSim Light only */
361 CurrentTSO->gran.clock = CurrentTime[CurrentProc];
364 event = get_next_event();
366 while (event!=(rtsEvent*)NULL) {
367 /* Choose the processor with the next event */
368 CurrentProc = event->proc;
369 CurrentTSO = event->tso;
373 while (!GlobalStopPending) { /* GlobalStopPending set in par_exit */
381 IF_DEBUG(scheduler, printAllThreads());
383 /* If we're interrupted (the user pressed ^C, or some other
384 * termination condition occurred), kill all the currently running
388 IF_DEBUG(scheduler, sched_belch("interrupted"));
390 interrupted = rtsFalse;
391 was_interrupted = rtsTrue;
394 /* Go through the list of main threads and wake up any
395 * clients whose computations have finished. ToDo: this
396 * should be done more efficiently without a linear scan
397 * of the main threads list, somehow...
401 StgMainThread *m, **prev;
402 prev = &main_threads;
403 for (m = main_threads; m != NULL; m = m->link) {
404 switch (m->tso->what_next) {
407 *(m->ret) = (StgClosure *)m->tso->sp[0];
411 pthread_cond_broadcast(&m->wakeup);
415 if (was_interrupted) {
416 m->stat = Interrupted;
420 pthread_cond_broadcast(&m->wakeup);
430 /* in GUM do this only on the Main PE */
433 /* If our main thread has finished or been killed, return.
436 StgMainThread *m = main_threads;
437 if (m->tso->what_next == ThreadComplete
438 || m->tso->what_next == ThreadKilled) {
439 main_threads = main_threads->link;
440 if (m->tso->what_next == ThreadComplete) {
441 /* we finished successfully, fill in the return value */
442 if (m->ret) { *(m->ret) = (StgClosure *)m->tso->sp[0]; };
446 if (was_interrupted) {
447 m->stat = Interrupted;
457 /* Top up the run queue from our spark pool. We try to make the
458 * number of threads in the run queue equal to the number of
463 nat n = n_free_capabilities;
464 StgTSO *tso = run_queue_hd;
466 /* Count the run queue */
467 while (n > 0 && tso != END_TSO_QUEUE) {
476 break; /* no more sparks in the pool */
478 /* I'd prefer this to be done in activateSpark -- HWL */
479 /* tricky - it needs to hold the scheduler lock and
480 * not try to re-acquire it -- SDM */
482 tso = createThread_(RtsFlags.GcFlags.initialStkSize, rtsTrue);
483 pushClosure(tso,spark);
484 PUSH_ON_RUN_QUEUE(tso);
486 advisory_thread_count++;
490 sched_belch("turning spark of closure %p into a thread",
491 (StgClosure *)spark));
494 /* We need to wake up the other tasks if we just created some
497 if (n_free_capabilities - n > 1) {
498 pthread_cond_signal(&thread_ready_cond);
503 /* Check whether any waiting threads need to be woken up. If the
504 * run queue is empty, and there are no other tasks running, we
505 * can wait indefinitely for something to happen.
506 * ToDo: what if another client comes along & requests another
509 if (blocked_queue_hd != END_TSO_QUEUE || sleeping_queue != END_TSO_QUEUE) {
511 (run_queue_hd == END_TSO_QUEUE)
513 && (n_free_capabilities == RtsFlags.ParFlags.nNodes)
517 /* we can be interrupted while waiting for I/O... */
518 if (interrupted) continue;
520 /* check for signals each time around the scheduler */
521 #ifndef mingw32_TARGET_OS
522 if (signals_pending()) {
523 start_signal_handlers();
528 * Detect deadlock: when we have no threads to run, there are no
529 * threads waiting on I/O or sleeping, and all the other tasks are
530 * waiting for work, we must have a deadlock of some description.
532 * We first try to find threads blocked on themselves (ie. black
533 * holes), and generate NonTermination exceptions where necessary.
535 * If no threads are black holed, we have a deadlock situation, so
536 * inform all the main threads.
539 if (blocked_queue_hd == END_TSO_QUEUE
540 && run_queue_hd == END_TSO_QUEUE
541 && sleeping_queue == END_TSO_QUEUE
542 && (n_free_capabilities == RtsFlags.ParFlags.nNodes))
544 IF_DEBUG(scheduler, sched_belch("deadlocked, checking for black holes..."));
546 if (run_queue_hd == END_TSO_QUEUE) {
548 for (m = main_threads; m != NULL; m = m->link) {
551 pthread_cond_broadcast(&m->wakeup);
557 if (blocked_queue_hd == END_TSO_QUEUE
558 && run_queue_hd == END_TSO_QUEUE
559 && sleeping_queue == END_TSO_QUEUE)
561 IF_DEBUG(scheduler, sched_belch("deadlocked, checking for black holes..."));
563 if (run_queue_hd == END_TSO_QUEUE) {
564 StgMainThread *m = main_threads;
567 main_threads = m->link;
574 /* If there's a GC pending, don't do anything until it has
578 IF_DEBUG(scheduler,sched_belch("waiting for GC"));
579 pthread_cond_wait(&gc_pending_cond, &sched_mutex);
582 /* block until we've got a thread on the run queue and a free
585 while (run_queue_hd == END_TSO_QUEUE || free_capabilities == NULL) {
586 IF_DEBUG(scheduler, sched_belch("waiting for work"));
587 pthread_cond_wait(&thread_ready_cond, &sched_mutex);
588 IF_DEBUG(scheduler, sched_belch("work now available"));
594 if (RtsFlags.GranFlags.Light)
595 GranSimLight_enter_system(event, &ActiveTSO); // adjust ActiveTSO etc
597 /* adjust time based on time-stamp */
598 if (event->time > CurrentTime[CurrentProc] &&
599 event->evttype != ContinueThread)
600 CurrentTime[CurrentProc] = event->time;
602 /* Deal with the idle PEs (may issue FindWork or MoveSpark events) */
603 if (!RtsFlags.GranFlags.Light)
606 IF_DEBUG(gran, fprintf(stderr, "GRAN: switch by event-type\n"))
608 /* main event dispatcher in GranSim */
609 switch (event->evttype) {
610 /* Should just be continuing execution */
612 IF_DEBUG(gran, fprintf(stderr, "GRAN: doing ContinueThread\n"));
613 /* ToDo: check assertion
614 ASSERT(run_queue_hd != (StgTSO*)NULL &&
615 run_queue_hd != END_TSO_QUEUE);
617 /* Ignore ContinueThreads for fetching threads (if synchr comm) */
618 if (!RtsFlags.GranFlags.DoAsyncFetch &&
619 procStatus[CurrentProc]==Fetching) {
620 belch("ghuH: Spurious ContinueThread while Fetching ignored; TSO %d (%p) [PE %d]",
621 CurrentTSO->id, CurrentTSO, CurrentProc);
624 /* Ignore ContinueThreads for completed threads */
625 if (CurrentTSO->what_next == ThreadComplete) {
626 belch("ghuH: found a ContinueThread event for completed thread %d (%p) [PE %d] (ignoring ContinueThread)",
627 CurrentTSO->id, CurrentTSO, CurrentProc);
630 /* Ignore ContinueThreads for threads that are being migrated */
631 if (PROCS(CurrentTSO)==Nowhere) {
632 belch("ghuH: trying to run the migrating TSO %d (%p) [PE %d] (ignoring ContinueThread)",
633 CurrentTSO->id, CurrentTSO, CurrentProc);
636 /* The thread should be at the beginning of the run queue */
637 if (CurrentTSO!=run_queue_hds[CurrentProc]) {
638 belch("ghuH: TSO %d (%p) [PE %d] is not at the start of the run_queue when doing a ContinueThread",
639 CurrentTSO->id, CurrentTSO, CurrentProc);
640 break; // run the thread anyway
643 new_event(proc, proc, CurrentTime[proc],
645 (StgTSO*)NULL, (StgClosure*)NULL, (rtsSpark*)NULL);
647 */ /* Catches superfluous CONTINUEs -- should be unnecessary */
648 break; // now actually run the thread; DaH Qu'vam yImuHbej
651 do_the_fetchnode(event);
652 goto next_thread; /* handle next event in event queue */
655 do_the_globalblock(event);
656 goto next_thread; /* handle next event in event queue */
659 do_the_fetchreply(event);
660 goto next_thread; /* handle next event in event queue */
662 case UnblockThread: /* Move from the blocked queue to the tail of */
663 do_the_unblock(event);
664 goto next_thread; /* handle next event in event queue */
666 case ResumeThread: /* Move from the blocked queue to the tail of */
667 /* the runnable queue ( i.e. Qu' SImqa'lu') */
668 event->tso->gran.blocktime +=
669 CurrentTime[CurrentProc] - event->tso->gran.blockedat;
670 do_the_startthread(event);
671 goto next_thread; /* handle next event in event queue */
674 do_the_startthread(event);
675 goto next_thread; /* handle next event in event queue */
678 do_the_movethread(event);
679 goto next_thread; /* handle next event in event queue */
682 do_the_movespark(event);
683 goto next_thread; /* handle next event in event queue */
686 do_the_findwork(event);
687 goto next_thread; /* handle next event in event queue */
690 barf("Illegal event type %u\n", event->evttype);
693 /* This point was scheduler_loop in the old RTS */
695 IF_DEBUG(gran, belch("GRAN: after main switch"));
697 TimeOfLastEvent = CurrentTime[CurrentProc];
698 TimeOfNextEvent = get_time_of_next_event();
699 IgnoreEvents=(TimeOfNextEvent==0); // HWL HACK
700 // CurrentTSO = ThreadQueueHd;
702 IF_DEBUG(gran, belch("GRAN: time of next event is: %ld",
705 if (RtsFlags.GranFlags.Light)
706 GranSimLight_leave_system(event, &ActiveTSO);
708 EndOfTimeSlice = CurrentTime[CurrentProc]+RtsFlags.GranFlags.time_slice;
711 belch("GRAN: end of time-slice is %#lx", EndOfTimeSlice));
713 /* in a GranSim setup the TSO stays on the run queue */
715 /* Take a thread from the run queue. */
716 t = POP_RUN_QUEUE(); // take_off_run_queue(t);
719 fprintf(stderr, "GRAN: About to run current thread, which is\n");
722 context_switch = 0; // turned on via GranYield, checking events and time slice
725 DumpGranEvent(GR_SCHEDULE, t));
727 procStatus[CurrentProc] = Busy;
731 if (PendingFetches != END_BF_QUEUE) {
735 /* ToDo: phps merge with spark activation above */
736 /* check whether we have local work and send requests if we have none */
737 if (run_queue_hd == END_TSO_QUEUE) { /* no runnable threads */
738 /* :-[ no local threads => look out for local sparks */
739 /* the spark pool for the current PE */
740 pool = &(MainRegTable.rSparks); // generalise to cap = &MainRegTable
741 if (advisory_thread_count < RtsFlags.ParFlags.maxThreads &&
742 pool->hd < pool->tl) {
744 * ToDo: add GC code check that we really have enough heap afterwards!!
746 * If we're here (no runnable threads) and we have pending
747 * sparks, we must have a space problem. Get enough space
748 * to turn one of those pending sparks into a
752 spark = findSpark(); /* get a spark */
753 if (spark != (rtsSpark) NULL) {
754 tso = activateSpark(spark); /* turn the spark into a thread */
755 IF_PAR_DEBUG(schedule,
756 belch("==== schedule: Created TSO %d (%p); %d threads active",
757 tso->id, tso, advisory_thread_count));
759 if (tso==END_TSO_QUEUE) { /* failed to activate spark->back to loop */
760 belch("==^^ failed to activate spark");
762 } /* otherwise fall through & pick-up new tso */
764 IF_PAR_DEBUG(verbose,
765 belch("==^^ no local sparks (spark pool contains only NFs: %d)",
766 spark_queue_len(pool)));
770 /* =8-[ no local sparks => look for work on other PEs */
773 * We really have absolutely no work. Send out a fish
774 * (there may be some out there already), and wait for
775 * something to arrive. We clearly can't run any threads
776 * until a SCHEDULE or RESUME arrives, and so that's what
777 * we're hoping to see. (Of course, we still have to
778 * respond to other types of messages.)
781 outstandingFishes < RtsFlags.ParFlags.maxFishes ) { // &&
782 // (last_fish_arrived_at+FISH_DELAY < CURRENT_TIME)) {
783 /* fishing set in sendFish, processFish;
784 avoid flooding system with fishes via delay */
786 sendFish(pe, mytid, NEW_FISH_AGE, NEW_FISH_HISTORY,
794 } else if (PacketsWaiting()) { /* Look for incoming messages */
798 /* Now we are sure that we have some work available */
799 ASSERT(run_queue_hd != END_TSO_QUEUE);
800 /* Take a thread from the run queue, if we have work */
801 t = POP_RUN_QUEUE(); // take_off_run_queue(END_TSO_QUEUE);
803 /* ToDo: write something to the log-file
804 if (RTSflags.ParFlags.granSimStats && !sameThread)
805 DumpGranEvent(GR_SCHEDULE, RunnableThreadsHd);
809 /* the spark pool for the current PE */
810 pool = &(MainRegTable.rSparks); // generalise to cap = &MainRegTable
812 IF_DEBUG(scheduler, belch("--^^ %d sparks on [%#x] (hd=%x; tl=%x; base=%x, lim=%x)",
813 spark_queue_len(pool),
815 pool->hd, pool->tl, pool->base, pool->lim));
817 IF_DEBUG(scheduler, belch("--== %d threads on [%#x] (hd=%x; tl=%x)",
818 run_queue_len(), CURRENT_PROC,
819 run_queue_hd, run_queue_tl));
824 we are running a different TSO, so write a schedule event to log file
825 NB: If we use fair scheduling we also have to write a deschedule
826 event for LastTSO; with unfair scheduling we know that the
827 previous tso has blocked whenever we switch to another tso, so
828 we don't need it in GUM for now
830 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
831 GR_SCHEDULE, t, (StgClosure *)NULL, 0, 0);
835 #else /* !GRAN && !PAR */
837 /* grab a thread from the run queue
839 ASSERT(run_queue_hd != END_TSO_QUEUE);
841 IF_DEBUG(sanity,checkTSO(t));
848 cap = free_capabilities;
849 free_capabilities = cap->link;
850 n_free_capabilities--;
855 cap->rCurrentTSO = t;
857 /* context switches are now initiated by the timer signal, unless
858 * the user specified "context switch as often as possible", with
861 if (RtsFlags.ConcFlags.ctxtSwitchTicks == 0
862 && (run_queue_hd != END_TSO_QUEUE
863 || blocked_queue_hd != END_TSO_QUEUE
864 || sleeping_queue != END_TSO_QUEUE))
869 RELEASE_LOCK(&sched_mutex);
871 IF_DEBUG(scheduler, sched_belch("-->> Running TSO %ld (%p) %s ...",
872 t->id, t, whatNext_strs[t->what_next]));
874 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
875 /* Run the current thread
877 switch (cap->rCurrentTSO->what_next) {
880 /* Thread already finished, return to scheduler. */
881 ret = ThreadFinished;
884 ret = StgRun((StgFunPtr) stg_enterStackTop, cap);
887 ret = StgRun((StgFunPtr) stg_returnToStackTop, cap);
889 case ThreadEnterInterp:
892 IF_DEBUG(scheduler,sched_belch("entering interpreter"));
893 ret = interpretBCO(cap);
897 barf("Panic: entered a BCO but no bytecode interpreter in this build");
900 barf("schedule: invalid what_next field");
902 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
904 /* Costs for the scheduler are assigned to CCS_SYSTEM */
909 ACQUIRE_LOCK(&sched_mutex);
912 IF_DEBUG(scheduler,fprintf(stderr,"scheduler (task %ld): ", pthread_self()););
913 #elif !defined(GRAN) && !defined(PAR)
914 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: "););
916 t = cap->rCurrentTSO;
919 /* HACK 675: if the last thread didn't yield, make sure to print a
920 SCHEDULE event to the log file when StgRunning the next thread, even
921 if it is the same one as before */
922 LastTSO = t; //(ret == ThreadBlocked) ? END_TSO_QUEUE : t;
923 TimeOfLastYield = CURRENT_TIME;
928 /* make all the running tasks block on a condition variable,
929 * maybe set context_switch and wait till they all pile in,
930 * then have them wait on a GC condition variable.
932 IF_DEBUG(scheduler,belch("--<< thread %ld (%p; %s) stopped: HeapOverflow",
933 t->id, t, whatNext_strs[t->what_next]));
936 ASSERT(!is_on_queue(t,CurrentProc));
939 ready_to_gc = rtsTrue;
940 context_switch = 1; /* stop other threads ASAP */
941 PUSH_ON_RUN_QUEUE(t);
942 /* actual GC is done at the end of the while loop */
946 IF_DEBUG(scheduler,belch("--<< thread %ld (%p; %s) stopped, StackOverflow",
947 t->id, t, whatNext_strs[t->what_next]));
948 /* just adjust the stack for this thread, then pop it back
954 /* enlarge the stack */
955 StgTSO *new_t = threadStackOverflow(t);
957 /* This TSO has moved, so update any pointers to it from the
958 * main thread stack. It better not be on any other queues...
961 for (m = main_threads; m != NULL; m = m->link) {
967 PUSH_ON_RUN_QUEUE(new_t);
974 DumpGranEvent(GR_DESCHEDULE, t));
975 globalGranStats.tot_yields++;
978 DumpGranEvent(GR_DESCHEDULE, t));
980 /* put the thread back on the run queue. Then, if we're ready to
981 * GC, check whether this is the last task to stop. If so, wake
982 * up the GC thread. getThread will block during a GC until the
986 if (t->what_next == ThreadEnterInterp) {
987 /* ToDo: or maybe a timer expired when we were in Hugs?
988 * or maybe someone hit ctrl-C
990 belch("--<< thread %ld (%p; %s) stopped to switch to Hugs",
991 t->id, t, whatNext_strs[t->what_next]);
993 belch("--<< thread %ld (%p; %s) stopped, yielding",
994 t->id, t, whatNext_strs[t->what_next]);
1001 //belch("&& Doing sanity check on yielding TSO %ld.", t->id);
1003 ASSERT(t->link == END_TSO_QUEUE);
1005 ASSERT(!is_on_queue(t,CurrentProc));
1008 //belch("&& Doing sanity check on all ThreadQueues (and their TSOs).");
1009 checkThreadQsSanity(rtsTrue));
1011 APPEND_TO_RUN_QUEUE(t);
1013 /* add a ContinueThread event to actually process the thread */
1014 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
1016 t, (StgClosure*)NULL, (rtsSpark*)NULL);
1018 belch("GRAN: eventq and runnableq after adding yielded thread to queue again:");
1027 belch("--<< thread %ld (%p; %s) stopped, blocking on node %p [PE %d] with BQ: ",
1028 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)));
1029 if (t->block_info.closure!=(StgClosure*)NULL) print_bq(t->block_info.closure));
1031 // ??? needed; should emit block before
1033 DumpGranEvent(GR_DESCHEDULE, t));
1034 prune_eventq(t, (StgClosure *)NULL); // prune ContinueThreads for t
1037 ASSERT(procStatus[CurrentProc]==Busy ||
1038 ((procStatus[CurrentProc]==Fetching) &&
1039 (t->block_info.closure!=(StgClosure*)NULL)));
1040 if (run_queue_hds[CurrentProc] == END_TSO_QUEUE &&
1041 !(!RtsFlags.GranFlags.DoAsyncFetch &&
1042 procStatus[CurrentProc]==Fetching))
1043 procStatus[CurrentProc] = Idle;
1047 DumpGranEvent(GR_DESCHEDULE, t));
1049 /* Send a fetch (if BlockedOnGA) and dump event to log file */
1053 belch("--<< thread %ld (%p; %s) stopped, blocking on node %p with BQ: ",
1054 t->id, t, whatNext_strs[t->what_next], t->block_info.closure);
1055 if (t->block_info.closure!=(StgClosure*)NULL) print_bq(t->block_info.closure));
1058 /* don't need to do anything. Either the thread is blocked on
1059 * I/O, in which case we'll have called addToBlockedQueue
1060 * previously, or it's blocked on an MVar or Blackhole, in which
1061 * case it'll be on the relevant queue already.
1064 fprintf(stderr, "--<< thread %d (%p) stopped: ", t->id, t);
1065 printThreadBlockage(t);
1066 fprintf(stderr, "\n"));
1068 /* Only for dumping event to log file
1069 ToDo: do I need this in GranSim, too?
1076 case ThreadFinished:
1077 /* Need to check whether this was a main thread, and if so, signal
1078 * the task that started it with the return value. If we have no
1079 * more main threads, we probably need to stop all the tasks until
1082 /* We also end up here if the thread kills itself with an
1083 * uncaught exception, see Exception.hc.
1085 IF_DEBUG(scheduler,belch("--++ thread %d (%p) finished", t->id, t));
1087 endThread(t, CurrentProc); // clean-up the thread
1089 advisory_thread_count--;
1090 if (RtsFlags.ParFlags.ParStats.Full)
1091 DumpEndEvent(CURRENT_PROC, t, rtsFalse /* not mandatory */);
1096 barf("schedule: invalid thread return code %d", (int)ret);
1100 cap->link = free_capabilities;
1101 free_capabilities = cap;
1102 n_free_capabilities++;
1106 if (ready_to_gc && n_free_capabilities == RtsFlags.ParFlags.nNodes)
1111 /* everybody back, start the GC.
1112 * Could do it in this thread, or signal a condition var
1113 * to do it in another thread. Either way, we need to
1114 * broadcast on gc_pending_cond afterward.
1117 IF_DEBUG(scheduler,sched_belch("doing GC"));
1119 GarbageCollect(GetRoots,rtsFalse);
1120 ready_to_gc = rtsFalse;
1122 pthread_cond_broadcast(&gc_pending_cond);
1125 /* add a ContinueThread event to continue execution of current thread */
1126 new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
1128 t, (StgClosure*)NULL, (rtsSpark*)NULL);
1130 fprintf(stderr, "GRAN: eventq and runnableq after Garbage collection:\n");
1137 IF_GRAN_DEBUG(unused,
1138 print_eventq(EventHd));
1140 event = get_next_event();
1144 /* ToDo: wait for next message to arrive rather than busy wait */
1149 t = take_off_run_queue(END_TSO_QUEUE);
1152 } /* end of while(1) */
1155 /* ---------------------------------------------------------------------------
1156 * deleteAllThreads(): kill all the live threads.
1158 * This is used when we catch a user interrupt (^C), before performing
1159 * any necessary cleanups and running finalizers.
1160 * ------------------------------------------------------------------------- */
1162 void deleteAllThreads ( void )
1165 IF_DEBUG(scheduler,sched_belch("deleting all threads"));
1166 for (t = run_queue_hd; t != END_TSO_QUEUE; t = t->link) {
1169 for (t = blocked_queue_hd; t != END_TSO_QUEUE; t = t->link) {
1172 for (t = sleeping_queue; t != END_TSO_QUEUE; t = t->link) {
1175 run_queue_hd = run_queue_tl = END_TSO_QUEUE;
1176 blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
1177 sleeping_queue = END_TSO_QUEUE;
1180 /* startThread and insertThread are now in GranSim.c -- HWL */
1182 //@node Suspend and Resume, Run queue code, Main scheduling loop, Main scheduling code
1183 //@subsection Suspend and Resume
1185 /* ---------------------------------------------------------------------------
1186 * Suspending & resuming Haskell threads.
1188 * When making a "safe" call to C (aka _ccall_GC), the task gives back
1189 * its capability before calling the C function. This allows another
1190 * task to pick up the capability and carry on running Haskell
1191 * threads. It also means that if the C call blocks, it won't lock
1194 * The Haskell thread making the C call is put to sleep for the
1195 * duration of the call, on the susepended_ccalling_threads queue. We
1196 * give out a token to the task, which it can use to resume the thread
1197 * on return from the C function.
1198 * ------------------------------------------------------------------------- */
1201 suspendThread( Capability *cap )
1205 ACQUIRE_LOCK(&sched_mutex);
1208 sched_belch("thread %d did a _ccall_gc", cap->rCurrentTSO->id));
1210 threadPaused(cap->rCurrentTSO);
1211 cap->rCurrentTSO->link = suspended_ccalling_threads;
1212 suspended_ccalling_threads = cap->rCurrentTSO;
1214 /* Use the thread ID as the token; it should be unique */
1215 tok = cap->rCurrentTSO->id;
1218 cap->link = free_capabilities;
1219 free_capabilities = cap;
1220 n_free_capabilities++;
1223 RELEASE_LOCK(&sched_mutex);
1228 resumeThread( StgInt tok )
1230 StgTSO *tso, **prev;
1233 ACQUIRE_LOCK(&sched_mutex);
1235 prev = &suspended_ccalling_threads;
1236 for (tso = suspended_ccalling_threads;
1237 tso != END_TSO_QUEUE;
1238 prev = &tso->link, tso = tso->link) {
1239 if (tso->id == (StgThreadID)tok) {
1244 if (tso == END_TSO_QUEUE) {
1245 barf("resumeThread: thread not found");
1247 tso->link = END_TSO_QUEUE;
1250 while (free_capabilities == NULL) {
1251 IF_DEBUG(scheduler, sched_belch("waiting to resume"));
1252 pthread_cond_wait(&thread_ready_cond, &sched_mutex);
1253 IF_DEBUG(scheduler, sched_belch("resuming thread %d", tso->id));
1255 cap = free_capabilities;
1256 free_capabilities = cap->link;
1257 n_free_capabilities--;
1259 cap = &MainRegTable;
1262 cap->rCurrentTSO = tso;
1264 RELEASE_LOCK(&sched_mutex);
1269 /* ---------------------------------------------------------------------------
1271 * ------------------------------------------------------------------------ */
1272 static void unblockThread(StgTSO *tso);
1274 /* ---------------------------------------------------------------------------
1275 * Comparing Thread ids.
1277 * This is used from STG land in the implementation of the
1278 * instances of Eq/Ord for ThreadIds.
1279 * ------------------------------------------------------------------------ */
1281 int cmp_thread(const StgTSO *tso1, const StgTSO *tso2)
1283 StgThreadID id1 = tso1->id;
1284 StgThreadID id2 = tso2->id;
1286 if (id1 < id2) return (-1);
1287 if (id1 > id2) return 1;
1291 /* ---------------------------------------------------------------------------
1292 Create a new thread.
1294 The new thread starts with the given stack size. Before the
1295 scheduler can run, however, this thread needs to have a closure
1296 (and possibly some arguments) pushed on its stack. See
1297 pushClosure() in Schedule.h.
1299 createGenThread() and createIOThread() (in SchedAPI.h) are
1300 convenient packaged versions of this function.
1302 currently pri (priority) is only used in a GRAN setup -- HWL
1303 ------------------------------------------------------------------------ */
1304 //@cindex createThread
1306 /* currently pri (priority) is only used in a GRAN setup -- HWL */
1308 createThread(nat stack_size, StgInt pri)
1310 return createThread_(stack_size, rtsFalse, pri);
1314 createThread_(nat size, rtsBool have_lock, StgInt pri)
1318 createThread(nat stack_size)
1320 return createThread_(stack_size, rtsFalse);
1324 createThread_(nat size, rtsBool have_lock)
1331 /* First check whether we should create a thread at all */
1333 /* check that no more than RtsFlags.ParFlags.maxThreads threads are created */
1334 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads) {
1336 belch("{createThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
1337 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
1338 return END_TSO_QUEUE;
1344 ASSERT(!RtsFlags.GranFlags.Light || CurrentProc==0);
1347 // ToDo: check whether size = stack_size - TSO_STRUCT_SIZEW
1349 /* catch ridiculously small stack sizes */
1350 if (size < MIN_STACK_WORDS + TSO_STRUCT_SIZEW) {
1351 size = MIN_STACK_WORDS + TSO_STRUCT_SIZEW;
1354 stack_size = size - TSO_STRUCT_SIZEW;
1356 tso = (StgTSO *)allocate(size);
1357 TICK_ALLOC_TSO(size-TSO_STRUCT_SIZEW, 0);
1359 SET_HDR(tso, &stg_TSO_info, CCS_SYSTEM);
1361 SET_GRAN_HDR(tso, ThisPE);
1363 tso->what_next = ThreadEnterGHC;
1365 /* tso->id needs to be unique. For now we use a heavyweight mutex to
1366 * protect the increment operation on next_thread_id.
1367 * In future, we could use an atomic increment instead.
1369 if (!have_lock) { ACQUIRE_LOCK(&sched_mutex); }
1370 tso->id = next_thread_id++;
1371 if (!have_lock) { RELEASE_LOCK(&sched_mutex); }
1373 tso->why_blocked = NotBlocked;
1374 tso->blocked_exceptions = NULL;
1376 tso->stack_size = stack_size;
1377 tso->max_stack_size = round_to_mblocks(RtsFlags.GcFlags.maxStkSize)
1379 tso->sp = (P_)&(tso->stack) + stack_size;
1382 tso->prof.CCCS = CCS_MAIN;
1385 /* put a stop frame on the stack */
1386 tso->sp -= sizeofW(StgStopFrame);
1387 SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_SYSTEM);
1388 tso->su = (StgUpdateFrame*)tso->sp;
1392 tso->link = END_TSO_QUEUE;
1393 /* uses more flexible routine in GranSim */
1394 insertThread(tso, CurrentProc);
1396 /* In a non-GranSim setup the pushing of a TSO onto the runq is separated
1401 #if defined(GRAN) || defined(PAR)
1402 DumpGranEvent(GR_START,tso);
1405 /* Link the new thread on the global thread list.
1407 tso->global_link = all_threads;
1411 tso->gran.pri = pri;
1413 tso->gran.magic = TSO_MAGIC; // debugging only
1415 tso->gran.sparkname = 0;
1416 tso->gran.startedat = CURRENT_TIME;
1417 tso->gran.exported = 0;
1418 tso->gran.basicblocks = 0;
1419 tso->gran.allocs = 0;
1420 tso->gran.exectime = 0;
1421 tso->gran.fetchtime = 0;
1422 tso->gran.fetchcount = 0;
1423 tso->gran.blocktime = 0;
1424 tso->gran.blockcount = 0;
1425 tso->gran.blockedat = 0;
1426 tso->gran.globalsparks = 0;
1427 tso->gran.localsparks = 0;
1428 if (RtsFlags.GranFlags.Light)
1429 tso->gran.clock = Now; /* local clock */
1431 tso->gran.clock = 0;
1433 IF_DEBUG(gran,printTSO(tso));
1436 tso->par.magic = TSO_MAGIC; // debugging only
1438 tso->par.sparkname = 0;
1439 tso->par.startedat = CURRENT_TIME;
1440 tso->par.exported = 0;
1441 tso->par.basicblocks = 0;
1442 tso->par.allocs = 0;
1443 tso->par.exectime = 0;
1444 tso->par.fetchtime = 0;
1445 tso->par.fetchcount = 0;
1446 tso->par.blocktime = 0;
1447 tso->par.blockcount = 0;
1448 tso->par.blockedat = 0;
1449 tso->par.globalsparks = 0;
1450 tso->par.localsparks = 0;
1454 globalGranStats.tot_threads_created++;
1455 globalGranStats.threads_created_on_PE[CurrentProc]++;
1456 globalGranStats.tot_sq_len += spark_queue_len(CurrentProc);
1457 globalGranStats.tot_sq_probes++;
1462 belch("==__ schedule: Created TSO %d (%p);",
1463 CurrentProc, tso, tso->id));
1465 IF_PAR_DEBUG(verbose,
1466 belch("==__ schedule: Created TSO %d (%p); %d threads active",
1467 tso->id, tso, advisory_thread_count));
1469 IF_DEBUG(scheduler,sched_belch("created thread %ld, stack size = %lx words",
1470 tso->id, tso->stack_size));
1476 Turn a spark into a thread.
1477 ToDo: fix for SMP (needs to acquire SCHED_MUTEX!)
1480 //@cindex activateSpark
1482 activateSpark (rtsSpark spark)
1486 ASSERT(spark != (rtsSpark)NULL);
1487 tso = createThread_(RtsFlags.GcFlags.initialStkSize, rtsTrue);
1488 if (tso!=END_TSO_QUEUE) {
1489 pushClosure(tso,spark);
1490 PUSH_ON_RUN_QUEUE(tso);
1491 advisory_thread_count++;
1493 if (RtsFlags.ParFlags.ParStats.Full) {
1494 //ASSERT(run_queue_hd == END_TSO_QUEUE); // I think ...
1495 IF_PAR_DEBUG(verbose,
1496 belch("==^^ activateSpark: turning spark of closure %p (%s) into a thread",
1497 (StgClosure *)spark, info_type((StgClosure *)spark)));
1500 barf("activateSpark: Cannot create TSO");
1502 // ToDo: fwd info on local/global spark to thread -- HWL
1503 // tso->gran.exported = spark->exported;
1504 // tso->gran.locked = !spark->global;
1505 // tso->gran.sparkname = spark->name;
1511 /* ---------------------------------------------------------------------------
1514 * scheduleThread puts a thread on the head of the runnable queue.
1515 * This will usually be done immediately after a thread is created.
1516 * The caller of scheduleThread must create the thread using e.g.
1517 * createThread and push an appropriate closure
1518 * on this thread's stack before the scheduler is invoked.
1519 * ------------------------------------------------------------------------ */
1522 scheduleThread(StgTSO *tso)
1524 if (tso==END_TSO_QUEUE){
1529 ACQUIRE_LOCK(&sched_mutex);
1531 /* Put the new thread on the head of the runnable queue. The caller
1532 * better push an appropriate closure on this thread's stack
1533 * beforehand. In the SMP case, the thread may start running as
1534 * soon as we release the scheduler lock below.
1536 PUSH_ON_RUN_QUEUE(tso);
1540 IF_DEBUG(scheduler,printTSO(tso));
1542 RELEASE_LOCK(&sched_mutex);
1545 /* ---------------------------------------------------------------------------
1548 * Start up Posix threads to run each of the scheduler tasks.
1549 * I believe the task ids are not needed in the system as defined.
1551 * ------------------------------------------------------------------------ */
1553 #if defined(PAR) || defined(SMP)
1555 taskStart( void *arg STG_UNUSED )
1557 rts_evalNothing(NULL);
1561 /* ---------------------------------------------------------------------------
1564 * Initialise the scheduler. This resets all the queues - if the
1565 * queues contained any threads, they'll be garbage collected at the
1568 * This now calls startTasks(), so should only be called once! KH @ 25/10/99
1569 * ------------------------------------------------------------------------ */
1573 term_handler(int sig STG_UNUSED)
1576 ACQUIRE_LOCK(&term_mutex);
1578 RELEASE_LOCK(&term_mutex);
1583 //@cindex initScheduler
1590 for (i=0; i<=MAX_PROC; i++) {
1591 run_queue_hds[i] = END_TSO_QUEUE;
1592 run_queue_tls[i] = END_TSO_QUEUE;
1593 blocked_queue_hds[i] = END_TSO_QUEUE;
1594 blocked_queue_tls[i] = END_TSO_QUEUE;
1595 ccalling_threadss[i] = END_TSO_QUEUE;
1596 sleeping_queue = END_TSO_QUEUE;
1599 run_queue_hd = END_TSO_QUEUE;
1600 run_queue_tl = END_TSO_QUEUE;
1601 blocked_queue_hd = END_TSO_QUEUE;
1602 blocked_queue_tl = END_TSO_QUEUE;
1603 sleeping_queue = END_TSO_QUEUE;
1606 suspended_ccalling_threads = END_TSO_QUEUE;
1608 main_threads = NULL;
1609 all_threads = END_TSO_QUEUE;
1614 RtsFlags.ConcFlags.ctxtSwitchTicks =
1615 RtsFlags.ConcFlags.ctxtSwitchTime / TICK_MILLISECS;
1618 ecafList = END_ECAF_LIST;
1622 /* Install the SIGHUP handler */
1625 struct sigaction action,oact;
1627 action.sa_handler = term_handler;
1628 sigemptyset(&action.sa_mask);
1629 action.sa_flags = 0;
1630 if (sigaction(SIGTERM, &action, &oact) != 0) {
1631 barf("can't install TERM handler");
1637 /* Allocate N Capabilities */
1640 Capability *cap, *prev;
1643 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1644 cap = stgMallocBytes(sizeof(Capability), "initScheduler:capabilities");
1648 free_capabilities = cap;
1649 n_free_capabilities = RtsFlags.ParFlags.nNodes;
1651 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: Allocated %d capabilities\n",
1652 n_free_capabilities););
1655 #if defined(SMP) || defined(PAR)
1668 /* make some space for saving all the thread ids */
1669 task_ids = stgMallocBytes(RtsFlags.ParFlags.nNodes * sizeof(task_info),
1670 "initScheduler:task_ids");
1672 /* and create all the threads */
1673 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1674 r = pthread_create(&tid,NULL,taskStart,NULL);
1676 barf("startTasks: Can't create new Posix thread");
1678 task_ids[i].id = tid;
1679 task_ids[i].mut_time = 0.0;
1680 task_ids[i].mut_etime = 0.0;
1681 task_ids[i].gc_time = 0.0;
1682 task_ids[i].gc_etime = 0.0;
1683 task_ids[i].elapsedtimestart = elapsedtime();
1684 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: Started task: %ld\n",tid););
1690 exitScheduler( void )
1695 /* Don't want to use pthread_cancel, since we'd have to install
1696 * these silly exception handlers (pthread_cleanup_{push,pop}) around
1700 /* Cancel all our tasks */
1701 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1702 pthread_cancel(task_ids[i].id);
1705 /* Wait for all the tasks to terminate */
1706 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1707 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: waiting for task %ld\n",
1709 pthread_join(task_ids[i].id, NULL);
1713 /* Send 'em all a SIGHUP. That should shut 'em up.
1715 await_death = RtsFlags.ParFlags.nNodes;
1716 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1717 pthread_kill(task_ids[i].id,SIGTERM);
1719 while (await_death > 0) {
1725 /* -----------------------------------------------------------------------------
1726 Managing the per-task allocation areas.
1728 Each capability comes with an allocation area. These are
1729 fixed-length block lists into which allocation can be done.
1731 ToDo: no support for two-space collection at the moment???
1732 -------------------------------------------------------------------------- */
1734 /* -----------------------------------------------------------------------------
1735 * waitThread is the external interface for running a new computation
1736 * and waiting for the result.
1738 * In the non-SMP case, we create a new main thread, push it on the
1739 * main-thread stack, and invoke the scheduler to run it. The
1740 * scheduler will return when the top main thread on the stack has
1741 * completed or died, and fill in the necessary fields of the
1742 * main_thread structure.
1744 * In the SMP case, we create a main thread as before, but we then
1745 * create a new condition variable and sleep on it. When our new
1746 * main thread has completed, we'll be woken up and the status/result
1747 * will be in the main_thread struct.
1748 * -------------------------------------------------------------------------- */
1751 howManyThreadsAvail ( void )
1755 for (q = run_queue_hd; q != END_TSO_QUEUE; q = q->link)
1757 for (q = blocked_queue_hd; q != END_TSO_QUEUE; q = q->link)
1759 for (q = sleeping_queue; q != END_TSO_QUEUE; q = q->link)
1765 finishAllThreads ( void )
1768 while (run_queue_hd != END_TSO_QUEUE) {
1769 waitThread ( run_queue_hd, NULL );
1771 while (blocked_queue_hd != END_TSO_QUEUE) {
1772 waitThread ( blocked_queue_hd, NULL );
1774 while (sleeping_queue != END_TSO_QUEUE) {
1775 waitThread ( blocked_queue_hd, NULL );
1778 (blocked_queue_hd != END_TSO_QUEUE ||
1779 run_queue_hd != END_TSO_QUEUE ||
1780 sleeping_queue != END_TSO_QUEUE);
1784 waitThread(StgTSO *tso, /*out*/StgClosure **ret)
1787 SchedulerStatus stat;
1789 ACQUIRE_LOCK(&sched_mutex);
1791 m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
1797 pthread_cond_init(&m->wakeup, NULL);
1800 m->link = main_threads;
1803 IF_DEBUG(scheduler, fprintf(stderr, "scheduler: new main thread (%d)\n",
1808 pthread_cond_wait(&m->wakeup, &sched_mutex);
1809 } while (m->stat == NoStatus);
1811 /* GranSim specific init */
1812 CurrentTSO = m->tso; // the TSO to run
1813 procStatus[MainProc] = Busy; // status of main PE
1814 CurrentProc = MainProc; // PE to run it on
1819 ASSERT(m->stat != NoStatus);
1825 pthread_cond_destroy(&m->wakeup);
1828 IF_DEBUG(scheduler, fprintf(stderr, "scheduler: main thread (%d) finished\n",
1832 RELEASE_LOCK(&sched_mutex);
1837 //@node Run queue code, Garbage Collextion Routines, Suspend and Resume, Main scheduling code
1838 //@subsection Run queue code
1842 NB: In GranSim we have many run queues; run_queue_hd is actually a macro
1843 unfolding to run_queue_hds[CurrentProc], thus CurrentProc is an
1844 implicit global variable that has to be correct when calling these
1848 /* Put the new thread on the head of the runnable queue.
1849 * The caller of createThread better push an appropriate closure
1850 * on this thread's stack before the scheduler is invoked.
1852 static /* inline */ void
1853 add_to_run_queue(tso)
1856 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
1857 tso->link = run_queue_hd;
1859 if (run_queue_tl == END_TSO_QUEUE) {
1864 /* Put the new thread at the end of the runnable queue. */
1865 static /* inline */ void
1866 push_on_run_queue(tso)
1869 ASSERT(get_itbl((StgClosure *)tso)->type == TSO);
1870 ASSERT(run_queue_hd!=NULL && run_queue_tl!=NULL);
1871 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
1872 if (run_queue_hd == END_TSO_QUEUE) {
1875 run_queue_tl->link = tso;
1881 Should be inlined because it's used very often in schedule. The tso
1882 argument is actually only needed in GranSim, where we want to have the
1883 possibility to schedule *any* TSO on the run queue, irrespective of the
1884 actual ordering. Therefore, if tso is not the nil TSO then we traverse
1885 the run queue and dequeue the tso, adjusting the links in the queue.
1887 //@cindex take_off_run_queue
1888 static /* inline */ StgTSO*
1889 take_off_run_queue(StgTSO *tso) {
1893 qetlaHbogh Qu' ngaSbogh ghomDaQ {tso} yIteq!
1895 if tso is specified, unlink that tso from the run_queue (doesn't have
1896 to be at the beginning of the queue); GranSim only
1898 if (tso!=END_TSO_QUEUE) {
1899 /* find tso in queue */
1900 for (t=run_queue_hd, prev=END_TSO_QUEUE;
1901 t!=END_TSO_QUEUE && t!=tso;
1905 /* now actually dequeue the tso */
1906 if (prev!=END_TSO_QUEUE) {
1907 ASSERT(run_queue_hd!=t);
1908 prev->link = t->link;
1910 /* t is at beginning of thread queue */
1911 ASSERT(run_queue_hd==t);
1912 run_queue_hd = t->link;
1914 /* t is at end of thread queue */
1915 if (t->link==END_TSO_QUEUE) {
1916 ASSERT(t==run_queue_tl);
1917 run_queue_tl = prev;
1919 ASSERT(run_queue_tl!=t);
1921 t->link = END_TSO_QUEUE;
1923 /* take tso from the beginning of the queue; std concurrent code */
1925 if (t != END_TSO_QUEUE) {
1926 run_queue_hd = t->link;
1927 t->link = END_TSO_QUEUE;
1928 if (run_queue_hd == END_TSO_QUEUE) {
1929 run_queue_tl = END_TSO_QUEUE;
1938 //@node Garbage Collextion Routines, Blocking Queue Routines, Run queue code, Main scheduling code
1939 //@subsection Garbage Collextion Routines
1941 /* ---------------------------------------------------------------------------
1942 Where are the roots that we know about?
1944 - all the threads on the runnable queue
1945 - all the threads on the blocked queue
1946 - all the threads on the sleeping queue
1947 - all the thread currently executing a _ccall_GC
1948 - all the "main threads"
1950 ------------------------------------------------------------------------ */
1952 /* This has to be protected either by the scheduler monitor, or by the
1953 garbage collection monitor (probably the latter).
1957 static void GetRoots(void)
1964 for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
1965 if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
1966 run_queue_hds[i] = (StgTSO *)MarkRoot((StgClosure *)run_queue_hds[i]);
1967 if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
1968 run_queue_tls[i] = (StgTSO *)MarkRoot((StgClosure *)run_queue_tls[i]);
1970 if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
1971 blocked_queue_hds[i] = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_hds[i]);
1972 if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
1973 blocked_queue_tls[i] = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_tls[i]);
1974 if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
1975 ccalling_threadss[i] = (StgTSO *)MarkRoot((StgClosure *)ccalling_threadss[i]);
1982 if (run_queue_hd != END_TSO_QUEUE) {
1983 ASSERT(run_queue_tl != END_TSO_QUEUE);
1984 run_queue_hd = (StgTSO *)MarkRoot((StgClosure *)run_queue_hd);
1985 run_queue_tl = (StgTSO *)MarkRoot((StgClosure *)run_queue_tl);
1988 if (blocked_queue_hd != END_TSO_QUEUE) {
1989 ASSERT(blocked_queue_tl != END_TSO_QUEUE);
1990 blocked_queue_hd = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_hd);
1991 blocked_queue_tl = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_tl);
1994 if (sleeping_queue != END_TSO_QUEUE) {
1995 sleeping_queue = (StgTSO *)MarkRoot((StgClosure *)sleeping_queue);
1999 for (m = main_threads; m != NULL; m = m->link) {
2000 m->tso = (StgTSO *)MarkRoot((StgClosure *)m->tso);
2002 if (suspended_ccalling_threads != END_TSO_QUEUE)
2003 suspended_ccalling_threads =
2004 (StgTSO *)MarkRoot((StgClosure *)suspended_ccalling_threads);
2006 #if defined(SMP) || defined(PAR) || defined(GRAN)
2015 /* -----------------------------------------------------------------------------
2018 This is the interface to the garbage collector from Haskell land.
2019 We provide this so that external C code can allocate and garbage
2020 collect when called from Haskell via _ccall_GC.
2022 It might be useful to provide an interface whereby the programmer
2023 can specify more roots (ToDo).
2025 This needs to be protected by the GC condition variable above. KH.
2026 -------------------------------------------------------------------------- */
2028 void (*extra_roots)(void);
2033 GarbageCollect(GetRoots,rtsFalse);
2037 performMajorGC(void)
2039 GarbageCollect(GetRoots,rtsTrue);
2045 GetRoots(); /* the scheduler's roots */
2046 extra_roots(); /* the user's roots */
2050 performGCWithRoots(void (*get_roots)(void))
2052 extra_roots = get_roots;
2054 GarbageCollect(AllRoots,rtsFalse);
2057 /* -----------------------------------------------------------------------------
2060 If the thread has reached its maximum stack size, then raise the
2061 StackOverflow exception in the offending thread. Otherwise
2062 relocate the TSO into a larger chunk of memory and adjust its stack
2064 -------------------------------------------------------------------------- */
2067 threadStackOverflow(StgTSO *tso)
2069 nat new_stack_size, new_tso_size, diff, stack_words;
2073 IF_DEBUG(sanity,checkTSO(tso));
2074 if (tso->stack_size >= tso->max_stack_size) {
2077 belch("@@ threadStackOverflow of TSO %d (%p): stack too large (now %ld; max is %ld",
2078 tso->id, tso, tso->stack_size, tso->max_stack_size);
2079 /* If we're debugging, just print out the top of the stack */
2080 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2084 fprintf(stderr, "fatal: stack overflow in Hugs; aborting\n" );
2087 /* Send this thread the StackOverflow exception */
2088 raiseAsync(tso, (StgClosure *)stackOverflow_closure);
2093 /* Try to double the current stack size. If that takes us over the
2094 * maximum stack size for this thread, then use the maximum instead.
2095 * Finally round up so the TSO ends up as a whole number of blocks.
2097 new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
2098 new_tso_size = (nat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
2099 TSO_STRUCT_SIZE)/sizeof(W_);
2100 new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
2101 new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
2103 IF_DEBUG(scheduler, fprintf(stderr,"scheduler: increasing stack size from %d words to %d.\n", tso->stack_size, new_stack_size));
2105 dest = (StgTSO *)allocate(new_tso_size);
2106 TICK_ALLOC_TSO(new_tso_size-sizeofW(StgTSO),0);
2108 /* copy the TSO block and the old stack into the new area */
2109 memcpy(dest,tso,TSO_STRUCT_SIZE);
2110 stack_words = tso->stack + tso->stack_size - tso->sp;
2111 new_sp = (P_)dest + new_tso_size - stack_words;
2112 memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
2114 /* relocate the stack pointers... */
2115 diff = (P_)new_sp - (P_)tso->sp; /* In *words* */
2116 dest->su = (StgUpdateFrame *) ((P_)dest->su + diff);
2118 dest->stack_size = new_stack_size;
2120 /* and relocate the update frame list */
2121 relocate_TSO(tso, dest);
2123 /* Mark the old TSO as relocated. We have to check for relocated
2124 * TSOs in the garbage collector and any primops that deal with TSOs.
2126 * It's important to set the sp and su values to just beyond the end
2127 * of the stack, so we don't attempt to scavenge any part of the
2130 tso->what_next = ThreadRelocated;
2132 tso->sp = (P_)&(tso->stack[tso->stack_size]);
2133 tso->su = (StgUpdateFrame *)tso->sp;
2134 tso->why_blocked = NotBlocked;
2135 dest->mut_link = NULL;
2137 IF_PAR_DEBUG(verbose,
2138 belch("@@ threadStackOverflow of TSO %d (now at %p): stack size increased to %ld",
2139 tso->id, tso, tso->stack_size);
2140 /* If we're debugging, just print out the top of the stack */
2141 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2144 IF_DEBUG(sanity,checkTSO(tso));
2146 IF_DEBUG(scheduler,printTSO(dest));
2152 //@node Blocking Queue Routines, Exception Handling Routines, Garbage Collextion Routines, Main scheduling code
2153 //@subsection Blocking Queue Routines
2155 /* ---------------------------------------------------------------------------
2156 Wake up a queue that was blocked on some resource.
2157 ------------------------------------------------------------------------ */
2161 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2166 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2168 /* write RESUME events to log file and
2169 update blocked and fetch time (depending on type of the orig closure) */
2170 if (RtsFlags.ParFlags.ParStats.Full) {
2171 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
2172 GR_RESUME, ((StgTSO *)bqe), ((StgTSO *)bqe)->block_info.closure,
2173 0, 0 /* spark_queue_len(ADVISORY_POOL) */);
2175 switch (get_itbl(node)->type) {
2177 ((StgTSO *)bqe)->par.fetchtime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2182 ((StgTSO *)bqe)->par.blocktime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2185 barf("{unblockOneLocked}Daq Qagh: unexpected closure in blocking queue");
2192 static StgBlockingQueueElement *
2193 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2196 PEs node_loc, tso_loc;
2198 node_loc = where_is(node); // should be lifted out of loop
2199 tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2200 tso_loc = where_is((StgClosure *)tso);
2201 if (IS_LOCAL_TO(PROCS(node),tso_loc)) { // TSO is local
2202 /* !fake_fetch => TSO is on CurrentProc is same as IS_LOCAL_TO */
2203 ASSERT(CurrentProc!=node_loc || tso_loc==CurrentProc);
2204 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.lunblocktime;
2205 // insertThread(tso, node_loc);
2206 new_event(tso_loc, tso_loc, CurrentTime[CurrentProc],
2208 tso, node, (rtsSpark*)NULL);
2209 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2212 } else { // TSO is remote (actually should be FMBQ)
2213 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.mpacktime +
2214 RtsFlags.GranFlags.Costs.gunblocktime +
2215 RtsFlags.GranFlags.Costs.latency;
2216 new_event(tso_loc, CurrentProc, CurrentTime[CurrentProc],
2218 tso, node, (rtsSpark*)NULL);
2219 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2222 /* the thread-queue-overhead is accounted for in either Resume or UnblockThread */
2224 fprintf(stderr," %s TSO %d (%p) [PE %d] (block_info.closure=%p) (next=%p) ,",
2225 (node_loc==tso_loc ? "Local" : "Global"),
2226 tso->id, tso, CurrentProc, tso->block_info.closure, tso->link));
2227 tso->block_info.closure = NULL;
2228 IF_DEBUG(scheduler,belch("-- Waking up thread %ld (%p)",
2232 static StgBlockingQueueElement *
2233 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2235 StgBlockingQueueElement *next;
2237 switch (get_itbl(bqe)->type) {
2239 ASSERT(((StgTSO *)bqe)->why_blocked != NotBlocked);
2240 /* if it's a TSO just push it onto the run_queue */
2242 // ((StgTSO *)bqe)->link = END_TSO_QUEUE; // debugging?
2243 PUSH_ON_RUN_QUEUE((StgTSO *)bqe);
2245 unblockCount(bqe, node);
2246 /* reset blocking status after dumping event */
2247 ((StgTSO *)bqe)->why_blocked = NotBlocked;
2251 /* if it's a BLOCKED_FETCH put it on the PendingFetches list */
2253 bqe->link = PendingFetches;
2254 PendingFetches = bqe;
2258 /* can ignore this case in a non-debugging setup;
2259 see comments on RBHSave closures above */
2261 /* check that the closure is an RBHSave closure */
2262 ASSERT(get_itbl((StgClosure *)bqe) == &stg_RBH_Save_0_info ||
2263 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_1_info ||
2264 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_2_info);
2268 barf("{unblockOneLocked}Daq Qagh: Unexpected IP (%#lx; %s) in blocking queue at %#lx\n",
2269 get_itbl((StgClosure *)bqe), info_type((StgClosure *)bqe),
2273 // IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
2277 #else /* !GRAN && !PAR */
2279 unblockOneLocked(StgTSO *tso)
2283 ASSERT(get_itbl(tso)->type == TSO);
2284 ASSERT(tso->why_blocked != NotBlocked);
2285 tso->why_blocked = NotBlocked;
2287 PUSH_ON_RUN_QUEUE(tso);
2289 IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
2294 #if defined(GRAN) || defined(PAR)
2295 inline StgBlockingQueueElement *
2296 unblockOne(StgBlockingQueueElement *bqe, StgClosure *node)
2298 ACQUIRE_LOCK(&sched_mutex);
2299 bqe = unblockOneLocked(bqe, node);
2300 RELEASE_LOCK(&sched_mutex);
2305 unblockOne(StgTSO *tso)
2307 ACQUIRE_LOCK(&sched_mutex);
2308 tso = unblockOneLocked(tso);
2309 RELEASE_LOCK(&sched_mutex);
2316 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2318 StgBlockingQueueElement *bqe;
2323 belch("## AwBQ for node %p on PE %d @ %ld by TSO %d (%p): ", \
2324 node, CurrentProc, CurrentTime[CurrentProc],
2325 CurrentTSO->id, CurrentTSO));
2327 node_loc = where_is(node);
2329 ASSERT(get_itbl(q)->type == TSO || // q is either a TSO or an RBHSave
2330 get_itbl(q)->type == CONSTR); // closure (type constructor)
2331 ASSERT(is_unique(node));
2333 /* FAKE FETCH: magically copy the node to the tso's proc;
2334 no Fetch necessary because in reality the node should not have been
2335 moved to the other PE in the first place
2337 if (CurrentProc!=node_loc) {
2339 belch("## node %p is on PE %d but CurrentProc is %d (TSO %d); assuming fake fetch and adjusting bitmask (old: %#x)",
2340 node, node_loc, CurrentProc, CurrentTSO->id,
2341 // CurrentTSO, where_is(CurrentTSO),
2342 node->header.gran.procs));
2343 node->header.gran.procs = (node->header.gran.procs) | PE_NUMBER(CurrentProc);
2345 belch("## new bitmask of node %p is %#x",
2346 node, node->header.gran.procs));
2347 if (RtsFlags.GranFlags.GranSimStats.Global) {
2348 globalGranStats.tot_fake_fetches++;
2353 // ToDo: check: ASSERT(CurrentProc==node_loc);
2354 while (get_itbl(bqe)->type==TSO) { // q != END_TSO_QUEUE) {
2357 bqe points to the current element in the queue
2358 next points to the next element in the queue
2360 //tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2361 //tso_loc = where_is(tso);
2363 bqe = unblockOneLocked(bqe, node);
2366 /* if this is the BQ of an RBH, we have to put back the info ripped out of
2367 the closure to make room for the anchor of the BQ */
2368 if (bqe!=END_BQ_QUEUE) {
2369 ASSERT(get_itbl(node)->type == RBH && get_itbl(bqe)->type == CONSTR);
2371 ASSERT((info_ptr==&RBH_Save_0_info) ||
2372 (info_ptr==&RBH_Save_1_info) ||
2373 (info_ptr==&RBH_Save_2_info));
2375 /* cf. convertToRBH in RBH.c for writing the RBHSave closure */
2376 ((StgRBH *)node)->blocking_queue = (StgBlockingQueueElement *)((StgRBHSave *)bqe)->payload[0];
2377 ((StgRBH *)node)->mut_link = (StgMutClosure *)((StgRBHSave *)bqe)->payload[1];
2380 belch("## Filled in RBH_Save for %p (%s) at end of AwBQ",
2381 node, info_type(node)));
2384 /* statistics gathering */
2385 if (RtsFlags.GranFlags.GranSimStats.Global) {
2386 // globalGranStats.tot_bq_processing_time += bq_processing_time;
2387 globalGranStats.tot_bq_len += len; // total length of all bqs awakened
2388 // globalGranStats.tot_bq_len_local += len_local; // same for local TSOs only
2389 globalGranStats.tot_awbq++; // total no. of bqs awakened
2392 fprintf(stderr,"## BQ Stats of %p: [%d entries] %s\n",
2393 node, len, (bqe!=END_BQ_QUEUE) ? "RBH" : ""));
2397 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2399 StgBlockingQueueElement *bqe, *next;
2401 ACQUIRE_LOCK(&sched_mutex);
2403 IF_PAR_DEBUG(verbose,
2404 belch("## AwBQ for node %p on [%x]: ",
2407 ASSERT(get_itbl(q)->type == TSO ||
2408 get_itbl(q)->type == BLOCKED_FETCH ||
2409 get_itbl(q)->type == CONSTR);
2412 while (get_itbl(bqe)->type==TSO ||
2413 get_itbl(bqe)->type==BLOCKED_FETCH) {
2414 bqe = unblockOneLocked(bqe, node);
2416 RELEASE_LOCK(&sched_mutex);
2419 #else /* !GRAN && !PAR */
2421 awakenBlockedQueue(StgTSO *tso)
2423 ACQUIRE_LOCK(&sched_mutex);
2424 while (tso != END_TSO_QUEUE) {
2425 tso = unblockOneLocked(tso);
2427 RELEASE_LOCK(&sched_mutex);
2431 //@node Exception Handling Routines, Debugging Routines, Blocking Queue Routines, Main scheduling code
2432 //@subsection Exception Handling Routines
2434 /* ---------------------------------------------------------------------------
2436 - usually called inside a signal handler so it mustn't do anything fancy.
2437 ------------------------------------------------------------------------ */
2440 interruptStgRts(void)
2446 /* -----------------------------------------------------------------------------
2449 This is for use when we raise an exception in another thread, which
2451 This has nothing to do with the UnblockThread event in GranSim. -- HWL
2452 -------------------------------------------------------------------------- */
2454 #if defined(GRAN) || defined(PAR)
2456 NB: only the type of the blocking queue is different in GranSim and GUM
2457 the operations on the queue-elements are the same
2458 long live polymorphism!
2461 unblockThread(StgTSO *tso)
2463 StgBlockingQueueElement *t, **last;
2465 ACQUIRE_LOCK(&sched_mutex);
2466 switch (tso->why_blocked) {
2469 return; /* not blocked */
2472 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
2474 StgBlockingQueueElement *last_tso = END_BQ_QUEUE;
2475 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
2477 last = (StgBlockingQueueElement **)&mvar->head;
2478 for (t = (StgBlockingQueueElement *)mvar->head;
2480 last = &t->link, last_tso = t, t = t->link) {
2481 if (t == (StgBlockingQueueElement *)tso) {
2482 *last = (StgBlockingQueueElement *)tso->link;
2483 if (mvar->tail == tso) {
2484 mvar->tail = (StgTSO *)last_tso;
2489 barf("unblockThread (MVAR): TSO not found");
2492 case BlockedOnBlackHole:
2493 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
2495 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
2497 last = &bq->blocking_queue;
2498 for (t = bq->blocking_queue;
2500 last = &t->link, t = t->link) {
2501 if (t == (StgBlockingQueueElement *)tso) {
2502 *last = (StgBlockingQueueElement *)tso->link;
2506 barf("unblockThread (BLACKHOLE): TSO not found");
2509 case BlockedOnException:
2511 StgTSO *target = tso->block_info.tso;
2513 ASSERT(get_itbl(target)->type == TSO);
2514 ASSERT(target->blocked_exceptions != NULL);
2516 last = (StgBlockingQueueElement **)&target->blocked_exceptions;
2517 for (t = (StgBlockingQueueElement *)target->blocked_exceptions;
2519 last = &t->link, t = t->link) {
2520 ASSERT(get_itbl(t)->type == TSO);
2521 if (t == (StgBlockingQueueElement *)tso) {
2522 *last = (StgBlockingQueueElement *)tso->link;
2526 barf("unblockThread (Exception): TSO not found");
2530 case BlockedOnWrite:
2532 StgBlockingQueueElement *prev = NULL;
2533 for (t = (StgBlockingQueueElement *)blocked_queue_hd; t != END_BQ_QUEUE;
2534 prev = t, t = t->link) {
2535 if (t == (StgBlockingQueueElement *)tso) {
2537 blocked_queue_hd = (StgTSO *)t->link;
2538 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
2539 blocked_queue_tl = END_TSO_QUEUE;
2542 prev->link = t->link;
2543 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
2544 blocked_queue_tl = (StgTSO *)prev;
2550 barf("unblockThread (I/O): TSO not found");
2553 case BlockedOnDelay:
2555 StgBlockingQueueElement *prev = NULL;
2556 for (t = (StgBlockingQueueElement *)sleeping_queue; t != END_BQ_QUEUE;
2557 prev = t, t = t->link) {
2558 if (t == (StgBlockingQueueElement *)tso) {
2560 sleeping_queue = (StgTSO *)t->link;
2562 prev->link = t->link;
2567 barf("unblockThread (I/O): TSO not found");
2571 barf("unblockThread");
2575 tso->link = END_TSO_QUEUE;
2576 tso->why_blocked = NotBlocked;
2577 tso->block_info.closure = NULL;
2578 PUSH_ON_RUN_QUEUE(tso);
2579 RELEASE_LOCK(&sched_mutex);
2583 unblockThread(StgTSO *tso)
2587 ACQUIRE_LOCK(&sched_mutex);
2588 switch (tso->why_blocked) {
2591 return; /* not blocked */
2594 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
2596 StgTSO *last_tso = END_TSO_QUEUE;
2597 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
2600 for (t = mvar->head; t != END_TSO_QUEUE;
2601 last = &t->link, last_tso = t, t = t->link) {
2604 if (mvar->tail == tso) {
2605 mvar->tail = last_tso;
2610 barf("unblockThread (MVAR): TSO not found");
2613 case BlockedOnBlackHole:
2614 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
2616 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
2618 last = &bq->blocking_queue;
2619 for (t = bq->blocking_queue; t != END_TSO_QUEUE;
2620 last = &t->link, t = t->link) {
2626 barf("unblockThread (BLACKHOLE): TSO not found");
2629 case BlockedOnException:
2631 StgTSO *target = tso->block_info.tso;
2633 ASSERT(get_itbl(target)->type == TSO);
2634 ASSERT(target->blocked_exceptions != NULL);
2636 last = &target->blocked_exceptions;
2637 for (t = target->blocked_exceptions; t != END_TSO_QUEUE;
2638 last = &t->link, t = t->link) {
2639 ASSERT(get_itbl(t)->type == TSO);
2645 barf("unblockThread (Exception): TSO not found");
2649 case BlockedOnWrite:
2651 StgTSO *prev = NULL;
2652 for (t = blocked_queue_hd; t != END_TSO_QUEUE;
2653 prev = t, t = t->link) {
2656 blocked_queue_hd = t->link;
2657 if (blocked_queue_tl == t) {
2658 blocked_queue_tl = END_TSO_QUEUE;
2661 prev->link = t->link;
2662 if (blocked_queue_tl == t) {
2663 blocked_queue_tl = prev;
2669 barf("unblockThread (I/O): TSO not found");
2672 case BlockedOnDelay:
2674 StgTSO *prev = NULL;
2675 for (t = sleeping_queue; t != END_TSO_QUEUE;
2676 prev = t, t = t->link) {
2679 sleeping_queue = t->link;
2681 prev->link = t->link;
2686 barf("unblockThread (I/O): TSO not found");
2690 barf("unblockThread");
2694 tso->link = END_TSO_QUEUE;
2695 tso->why_blocked = NotBlocked;
2696 tso->block_info.closure = NULL;
2697 PUSH_ON_RUN_QUEUE(tso);
2698 RELEASE_LOCK(&sched_mutex);
2702 /* -----------------------------------------------------------------------------
2705 * The following function implements the magic for raising an
2706 * asynchronous exception in an existing thread.
2708 * We first remove the thread from any queue on which it might be
2709 * blocked. The possible blockages are MVARs and BLACKHOLE_BQs.
2711 * We strip the stack down to the innermost CATCH_FRAME, building
2712 * thunks in the heap for all the active computations, so they can
2713 * be restarted if necessary. When we reach a CATCH_FRAME, we build
2714 * an application of the handler to the exception, and push it on
2715 * the top of the stack.
2717 * How exactly do we save all the active computations? We create an
2718 * AP_UPD for every UpdateFrame on the stack. Entering one of these
2719 * AP_UPDs pushes everything from the corresponding update frame
2720 * upwards onto the stack. (Actually, it pushes everything up to the
2721 * next update frame plus a pointer to the next AP_UPD object.
2722 * Entering the next AP_UPD object pushes more onto the stack until we
2723 * reach the last AP_UPD object - at which point the stack should look
2724 * exactly as it did when we killed the TSO and we can continue
2725 * execution by entering the closure on top of the stack.
2727 * We can also kill a thread entirely - this happens if either (a) the
2728 * exception passed to raiseAsync is NULL, or (b) there's no
2729 * CATCH_FRAME on the stack. In either case, we strip the entire
2730 * stack and replace the thread with a zombie.
2732 * -------------------------------------------------------------------------- */
2735 deleteThread(StgTSO *tso)
2737 raiseAsync(tso,NULL);
2741 raiseAsync(StgTSO *tso, StgClosure *exception)
2743 StgUpdateFrame* su = tso->su;
2744 StgPtr sp = tso->sp;
2746 /* Thread already dead? */
2747 if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) {
2751 IF_DEBUG(scheduler, sched_belch("raising exception in thread %ld.", tso->id));
2753 /* Remove it from any blocking queues */
2756 /* The stack freezing code assumes there's a closure pointer on
2757 * the top of the stack. This isn't always the case with compiled
2758 * code, so we have to push a dummy closure on the top which just
2759 * returns to the next return address on the stack.
2761 if ( LOOKS_LIKE_GHC_INFO((void*)*sp) ) {
2762 *(--sp) = (W_)&stg_dummy_ret_closure;
2766 int words = ((P_)su - (P_)sp) - 1;
2770 /* If we find a CATCH_FRAME, and we've got an exception to raise,
2771 * then build PAP(handler,exception,realworld#), and leave it on
2772 * top of the stack ready to enter.
2774 if (get_itbl(su)->type == CATCH_FRAME && exception != NULL) {
2775 StgCatchFrame *cf = (StgCatchFrame *)su;
2776 /* we've got an exception to raise, so let's pass it to the
2777 * handler in this frame.
2779 ap = (StgAP_UPD *)allocate(sizeofW(StgPAP) + 2);
2780 TICK_ALLOC_UPD_PAP(3,0);
2781 SET_HDR(ap,&stg_PAP_info,cf->header.prof.ccs);
2784 ap->fun = cf->handler; /* :: Exception -> IO a */
2785 ap->payload[0] = exception;
2786 ap->payload[1] = ARG_TAG(0); /* realworld token */
2788 /* throw away the stack from Sp up to and including the
2791 sp = (P_)su + sizeofW(StgCatchFrame) - 1;
2794 /* Restore the blocked/unblocked state for asynchronous exceptions
2795 * at the CATCH_FRAME.
2797 * If exceptions were unblocked at the catch, arrange that they
2798 * are unblocked again after executing the handler by pushing an
2799 * unblockAsyncExceptions_ret stack frame.
2801 if (!cf->exceptions_blocked) {
2802 *(sp--) = (W_)&stg_unblockAsyncExceptionszh_ret_info;
2805 /* Ensure that async exceptions are blocked when running the handler.
2807 if (tso->blocked_exceptions == NULL) {
2808 tso->blocked_exceptions = END_TSO_QUEUE;
2811 /* Put the newly-built PAP on top of the stack, ready to execute
2812 * when the thread restarts.
2816 tso->what_next = ThreadEnterGHC;
2817 IF_DEBUG(sanity, checkTSO(tso));
2821 /* First build an AP_UPD consisting of the stack chunk above the
2822 * current update frame, with the top word on the stack as the
2825 ap = (StgAP_UPD *)allocate(AP_sizeW(words));
2830 ap->fun = (StgClosure *)sp[0];
2832 for(i=0; i < (nat)words; ++i) {
2833 ap->payload[i] = (StgClosure *)*sp++;
2836 switch (get_itbl(su)->type) {
2840 SET_HDR(ap,&stg_AP_UPD_info,su->header.prof.ccs /* ToDo */);
2841 TICK_ALLOC_UP_THK(words+1,0);
2844 fprintf(stderr, "scheduler: Updating ");
2845 printPtr((P_)su->updatee);
2846 fprintf(stderr, " with ");
2847 printObj((StgClosure *)ap);
2850 /* Replace the updatee with an indirection - happily
2851 * this will also wake up any threads currently
2852 * waiting on the result.
2854 UPD_IND_NOLOCK(su->updatee,ap); /* revert the black hole */
2856 sp += sizeofW(StgUpdateFrame) -1;
2857 sp[0] = (W_)ap; /* push onto stack */
2863 StgCatchFrame *cf = (StgCatchFrame *)su;
2866 /* We want a PAP, not an AP_UPD. Fortunately, the
2867 * layout's the same.
2869 SET_HDR(ap,&stg_PAP_info,su->header.prof.ccs /* ToDo */);
2870 TICK_ALLOC_UPD_PAP(words+1,0);
2872 /* now build o = FUN(catch,ap,handler) */
2873 o = (StgClosure *)allocate(sizeofW(StgClosure)+2);
2874 TICK_ALLOC_FUN(2,0);
2875 SET_HDR(o,&stg_catch_info,su->header.prof.ccs /* ToDo */);
2876 o->payload[0] = (StgClosure *)ap;
2877 o->payload[1] = cf->handler;
2880 fprintf(stderr, "scheduler: Built ");
2881 printObj((StgClosure *)o);
2884 /* pop the old handler and put o on the stack */
2886 sp += sizeofW(StgCatchFrame) - 1;
2893 StgSeqFrame *sf = (StgSeqFrame *)su;
2896 SET_HDR(ap,&stg_PAP_info,su->header.prof.ccs /* ToDo */);
2897 TICK_ALLOC_UPD_PAP(words+1,0);
2899 /* now build o = FUN(seq,ap) */
2900 o = (StgClosure *)allocate(sizeofW(StgClosure)+1);
2901 TICK_ALLOC_SE_THK(1,0);
2902 SET_HDR(o,&stg_seq_info,su->header.prof.ccs /* ToDo */);
2903 o->payload[0] = (StgClosure *)ap;
2906 fprintf(stderr, "scheduler: Built ");
2907 printObj((StgClosure *)o);
2910 /* pop the old handler and put o on the stack */
2912 sp += sizeofW(StgSeqFrame) - 1;
2918 /* We've stripped the entire stack, the thread is now dead. */
2919 sp += sizeofW(StgStopFrame) - 1;
2920 sp[0] = (W_)exception; /* save the exception */
2921 tso->what_next = ThreadKilled;
2922 tso->su = (StgUpdateFrame *)(sp+1);
2933 /* -----------------------------------------------------------------------------
2934 resurrectThreads is called after garbage collection on the list of
2935 threads found to be garbage. Each of these threads will be woken
2936 up and sent a signal: BlockedOnDeadMVar if the thread was blocked
2937 on an MVar, or NonTermination if the thread was blocked on a Black
2939 -------------------------------------------------------------------------- */
2942 resurrectThreads( StgTSO *threads )
2946 for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
2947 next = tso->global_link;
2948 tso->global_link = all_threads;
2950 IF_DEBUG(scheduler, sched_belch("resurrecting thread %d", tso->id));
2952 switch (tso->why_blocked) {
2954 case BlockedOnException:
2955 raiseAsync(tso,(StgClosure *)BlockedOnDeadMVar_closure);
2957 case BlockedOnBlackHole:
2958 raiseAsync(tso,(StgClosure *)NonTermination_closure);
2961 /* This might happen if the thread was blocked on a black hole
2962 * belonging to a thread that we've just woken up (raiseAsync
2963 * can wake up threads, remember...).
2967 barf("resurrectThreads: thread blocked in a strange way");
2972 /* -----------------------------------------------------------------------------
2973 * Blackhole detection: if we reach a deadlock, test whether any
2974 * threads are blocked on themselves. Any threads which are found to
2975 * be self-blocked get sent a NonTermination exception.
2977 * This is only done in a deadlock situation in order to avoid
2978 * performance overhead in the normal case.
2979 * -------------------------------------------------------------------------- */
2982 detectBlackHoles( void )
2984 StgTSO *t = all_threads;
2985 StgUpdateFrame *frame;
2986 StgClosure *blocked_on;
2988 for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
2990 if (t->why_blocked != BlockedOnBlackHole) {
2994 blocked_on = t->block_info.closure;
2996 for (frame = t->su; ; frame = frame->link) {
2997 switch (get_itbl(frame)->type) {
3000 if (frame->updatee == blocked_on) {
3001 /* We are blocking on one of our own computations, so
3002 * send this thread the NonTermination exception.
3005 sched_belch("thread %d is blocked on itself", t->id));
3006 raiseAsync(t, (StgClosure *)NonTermination_closure);
3027 //@node Debugging Routines, Index, Exception Handling Routines, Main scheduling code
3028 //@subsection Debugging Routines
3030 /* -----------------------------------------------------------------------------
3031 Debugging: why is a thread blocked
3032 -------------------------------------------------------------------------- */
3037 printThreadBlockage(StgTSO *tso)
3039 switch (tso->why_blocked) {
3041 fprintf(stderr,"is blocked on read from fd %d", tso->block_info.fd);
3043 case BlockedOnWrite:
3044 fprintf(stderr,"is blocked on write to fd %d", tso->block_info.fd);
3046 case BlockedOnDelay:
3047 fprintf(stderr,"is blocked until %d", tso->block_info.target);
3050 fprintf(stderr,"is blocked on an MVar");
3052 case BlockedOnException:
3053 fprintf(stderr,"is blocked on delivering an exception to thread %d",
3054 tso->block_info.tso->id);
3056 case BlockedOnBlackHole:
3057 fprintf(stderr,"is blocked on a black hole");
3060 fprintf(stderr,"is not blocked");
3064 fprintf(stderr,"is blocked on global address; local FM_BQ is %p (%s)",
3065 tso->block_info.closure, info_type(tso->block_info.closure));
3067 case BlockedOnGA_NoSend:
3068 fprintf(stderr,"is blocked on global address (no send); local FM_BQ is %p (%s)",
3069 tso->block_info.closure, info_type(tso->block_info.closure));
3073 barf("printThreadBlockage: strange tso->why_blocked: %d for TSO %d (%d)",
3074 tso->why_blocked, tso->id, tso);
3079 printThreadStatus(StgTSO *tso)
3081 switch (tso->what_next) {
3083 fprintf(stderr,"has been killed");
3085 case ThreadComplete:
3086 fprintf(stderr,"has completed");
3089 printThreadBlockage(tso);
3094 printAllThreads(void)
3098 sched_belch("all threads:");
3099 for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
3100 fprintf(stderr, "\tthread %d ", t->id);
3101 printThreadStatus(t);
3102 fprintf(stderr,"\n");
3107 Print a whole blocking queue attached to node (debugging only).
3112 print_bq (StgClosure *node)
3114 StgBlockingQueueElement *bqe;
3118 fprintf(stderr,"## BQ of closure %p (%s): ",
3119 node, info_type(node));
3121 /* should cover all closures that may have a blocking queue */
3122 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3123 get_itbl(node)->type == FETCH_ME_BQ ||
3124 get_itbl(node)->type == RBH);
3126 ASSERT(node!=(StgClosure*)NULL); // sanity check
3128 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3130 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
3131 !end; // iterate until bqe points to a CONSTR
3132 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
3133 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3134 ASSERT(bqe != (StgTSO*)NULL); // sanity check
3135 /* types of closures that may appear in a blocking queue */
3136 ASSERT(get_itbl(bqe)->type == TSO ||
3137 get_itbl(bqe)->type == BLOCKED_FETCH ||
3138 get_itbl(bqe)->type == CONSTR);
3139 /* only BQs of an RBH end with an RBH_Save closure */
3140 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3142 switch (get_itbl(bqe)->type) {
3144 fprintf(stderr," TSO %d (%x),",
3145 ((StgTSO *)bqe)->id, ((StgTSO *)bqe));
3148 fprintf(stderr," BF (node=%p, ga=((%x, %d, %x)),",
3149 ((StgBlockedFetch *)bqe)->node,
3150 ((StgBlockedFetch *)bqe)->ga.payload.gc.gtid,
3151 ((StgBlockedFetch *)bqe)->ga.payload.gc.slot,
3152 ((StgBlockedFetch *)bqe)->ga.weight);
3155 fprintf(stderr," %s (IP %p),",
3156 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3157 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3158 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3159 "RBH_Save_?"), get_itbl(bqe));
3162 barf("Unexpected closure type %s in blocking queue of %p (%s)",
3163 info_type(bqe), node, info_type(node));
3167 fputc('\n', stderr);
3169 # elif defined(GRAN)
3171 print_bq (StgClosure *node)
3173 StgBlockingQueueElement *bqe;
3174 PEs node_loc, tso_loc;
3177 /* should cover all closures that may have a blocking queue */
3178 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3179 get_itbl(node)->type == FETCH_ME_BQ ||
3180 get_itbl(node)->type == RBH);
3182 ASSERT(node!=(StgClosure*)NULL); // sanity check
3183 node_loc = where_is(node);
3185 fprintf(stderr,"## BQ of closure %p (%s) on [PE %d]: ",
3186 node, info_type(node), node_loc);
3189 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3191 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
3192 !end; // iterate until bqe points to a CONSTR
3193 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
3194 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3195 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
3196 /* types of closures that may appear in a blocking queue */
3197 ASSERT(get_itbl(bqe)->type == TSO ||
3198 get_itbl(bqe)->type == CONSTR);
3199 /* only BQs of an RBH end with an RBH_Save closure */
3200 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3202 tso_loc = where_is((StgClosure *)bqe);
3203 switch (get_itbl(bqe)->type) {
3205 fprintf(stderr," TSO %d (%p) on [PE %d],",
3206 ((StgTSO *)bqe)->id, (StgTSO *)bqe, tso_loc);
3209 fprintf(stderr," %s (IP %p),",
3210 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3211 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3212 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3213 "RBH_Save_?"), get_itbl(bqe));
3216 barf("Unexpected closure type %s in blocking queue of %p (%s)",
3217 info_type((StgClosure *)bqe), node, info_type(node));
3221 fputc('\n', stderr);
3225 Nice and easy: only TSOs on the blocking queue
3228 print_bq (StgClosure *node)
3232 ASSERT(node!=(StgClosure*)NULL); // sanity check
3233 for (tso = ((StgBlockingQueue*)node)->blocking_queue;
3234 tso != END_TSO_QUEUE;
3236 ASSERT(tso!=NULL && tso!=END_TSO_QUEUE); // sanity check
3237 ASSERT(get_itbl(tso)->type == TSO); // guess what, sanity check
3238 fprintf(stderr," TSO %d (%p),", tso->id, tso);
3240 fputc('\n', stderr);
3251 for (i=0, tso=run_queue_hd;
3252 tso != END_TSO_QUEUE;
3261 sched_belch(char *s, ...)
3266 fprintf(stderr, "scheduler (task %ld): ", pthread_self());
3268 fprintf(stderr, "scheduler: ");
3270 vfprintf(stderr, s, ap);
3271 fprintf(stderr, "\n");
3277 //@node Index, , Debugging Routines, Main scheduling code
3281 //* MainRegTable:: @cindex\s-+MainRegTable
3282 //* StgMainThread:: @cindex\s-+StgMainThread
3283 //* awaken_blocked_queue:: @cindex\s-+awaken_blocked_queue
3284 //* blocked_queue_hd:: @cindex\s-+blocked_queue_hd
3285 //* blocked_queue_tl:: @cindex\s-+blocked_queue_tl
3286 //* context_switch:: @cindex\s-+context_switch
3287 //* createThread:: @cindex\s-+createThread
3288 //* free_capabilities:: @cindex\s-+free_capabilities
3289 //* gc_pending_cond:: @cindex\s-+gc_pending_cond
3290 //* initScheduler:: @cindex\s-+initScheduler
3291 //* interrupted:: @cindex\s-+interrupted
3292 //* n_free_capabilities:: @cindex\s-+n_free_capabilities
3293 //* next_thread_id:: @cindex\s-+next_thread_id
3294 //* print_bq:: @cindex\s-+print_bq
3295 //* run_queue_hd:: @cindex\s-+run_queue_hd
3296 //* run_queue_tl:: @cindex\s-+run_queue_tl
3297 //* sched_mutex:: @cindex\s-+sched_mutex
3298 //* schedule:: @cindex\s-+schedule
3299 //* take_off_run_queue:: @cindex\s-+take_off_run_queue
3300 //* task_ids:: @cindex\s-+task_ids
3301 //* term_mutex:: @cindex\s-+term_mutex
3302 //* thread_ready_cond:: @cindex\s-+thread_ready_cond