1 /* ---------------------------------------------------------------------------
2 * $Id: Schedule.c,v 1.85 2000/12/19 16:38:15 sewardj 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)
2011 /* -----------------------------------------------------------------------------
2014 This is the interface to the garbage collector from Haskell land.
2015 We provide this so that external C code can allocate and garbage
2016 collect when called from Haskell via _ccall_GC.
2018 It might be useful to provide an interface whereby the programmer
2019 can specify more roots (ToDo).
2021 This needs to be protected by the GC condition variable above. KH.
2022 -------------------------------------------------------------------------- */
2024 void (*extra_roots)(void);
2029 GarbageCollect(GetRoots,rtsFalse);
2033 performMajorGC(void)
2035 GarbageCollect(GetRoots,rtsTrue);
2041 GetRoots(); /* the scheduler's roots */
2042 extra_roots(); /* the user's roots */
2046 performGCWithRoots(void (*get_roots)(void))
2048 extra_roots = get_roots;
2050 GarbageCollect(AllRoots,rtsFalse);
2053 /* -----------------------------------------------------------------------------
2056 If the thread has reached its maximum stack size, then raise the
2057 StackOverflow exception in the offending thread. Otherwise
2058 relocate the TSO into a larger chunk of memory and adjust its stack
2060 -------------------------------------------------------------------------- */
2063 threadStackOverflow(StgTSO *tso)
2065 nat new_stack_size, new_tso_size, diff, stack_words;
2069 IF_DEBUG(sanity,checkTSO(tso));
2070 if (tso->stack_size >= tso->max_stack_size) {
2073 belch("@@ threadStackOverflow of TSO %d (%p): stack too large (now %ld; max is %ld",
2074 tso->id, tso, tso->stack_size, tso->max_stack_size);
2075 /* If we're debugging, just print out the top of the stack */
2076 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2080 fprintf(stderr, "fatal: stack overflow in Hugs; aborting\n" );
2083 /* Send this thread the StackOverflow exception */
2084 raiseAsync(tso, (StgClosure *)stackOverflow_closure);
2089 /* Try to double the current stack size. If that takes us over the
2090 * maximum stack size for this thread, then use the maximum instead.
2091 * Finally round up so the TSO ends up as a whole number of blocks.
2093 new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
2094 new_tso_size = (nat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
2095 TSO_STRUCT_SIZE)/sizeof(W_);
2096 new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
2097 new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
2099 IF_DEBUG(scheduler, fprintf(stderr,"scheduler: increasing stack size from %d words to %d.\n", tso->stack_size, new_stack_size));
2101 dest = (StgTSO *)allocate(new_tso_size);
2102 TICK_ALLOC_TSO(new_tso_size-sizeofW(StgTSO),0);
2104 /* copy the TSO block and the old stack into the new area */
2105 memcpy(dest,tso,TSO_STRUCT_SIZE);
2106 stack_words = tso->stack + tso->stack_size - tso->sp;
2107 new_sp = (P_)dest + new_tso_size - stack_words;
2108 memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
2110 /* relocate the stack pointers... */
2111 diff = (P_)new_sp - (P_)tso->sp; /* In *words* */
2112 dest->su = (StgUpdateFrame *) ((P_)dest->su + diff);
2114 dest->stack_size = new_stack_size;
2116 /* and relocate the update frame list */
2117 relocate_TSO(tso, dest);
2119 /* Mark the old TSO as relocated. We have to check for relocated
2120 * TSOs in the garbage collector and any primops that deal with TSOs.
2122 * It's important to set the sp and su values to just beyond the end
2123 * of the stack, so we don't attempt to scavenge any part of the
2126 tso->what_next = ThreadRelocated;
2128 tso->sp = (P_)&(tso->stack[tso->stack_size]);
2129 tso->su = (StgUpdateFrame *)tso->sp;
2130 tso->why_blocked = NotBlocked;
2131 dest->mut_link = NULL;
2133 IF_PAR_DEBUG(verbose,
2134 belch("@@ threadStackOverflow of TSO %d (now at %p): stack size increased to %ld",
2135 tso->id, tso, tso->stack_size);
2136 /* If we're debugging, just print out the top of the stack */
2137 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
2140 IF_DEBUG(sanity,checkTSO(tso));
2142 IF_DEBUG(scheduler,printTSO(dest));
2148 //@node Blocking Queue Routines, Exception Handling Routines, Garbage Collextion Routines, Main scheduling code
2149 //@subsection Blocking Queue Routines
2151 /* ---------------------------------------------------------------------------
2152 Wake up a queue that was blocked on some resource.
2153 ------------------------------------------------------------------------ */
2157 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2162 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
2164 /* write RESUME events to log file and
2165 update blocked and fetch time (depending on type of the orig closure) */
2166 if (RtsFlags.ParFlags.ParStats.Full) {
2167 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
2168 GR_RESUME, ((StgTSO *)bqe), ((StgTSO *)bqe)->block_info.closure,
2169 0, 0 /* spark_queue_len(ADVISORY_POOL) */);
2171 switch (get_itbl(node)->type) {
2173 ((StgTSO *)bqe)->par.fetchtime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2178 ((StgTSO *)bqe)->par.blocktime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
2181 barf("{unblockOneLocked}Daq Qagh: unexpected closure in blocking queue");
2188 static StgBlockingQueueElement *
2189 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2192 PEs node_loc, tso_loc;
2194 node_loc = where_is(node); // should be lifted out of loop
2195 tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2196 tso_loc = where_is((StgClosure *)tso);
2197 if (IS_LOCAL_TO(PROCS(node),tso_loc)) { // TSO is local
2198 /* !fake_fetch => TSO is on CurrentProc is same as IS_LOCAL_TO */
2199 ASSERT(CurrentProc!=node_loc || tso_loc==CurrentProc);
2200 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.lunblocktime;
2201 // insertThread(tso, node_loc);
2202 new_event(tso_loc, tso_loc, CurrentTime[CurrentProc],
2204 tso, node, (rtsSpark*)NULL);
2205 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2208 } else { // TSO is remote (actually should be FMBQ)
2209 CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.mpacktime +
2210 RtsFlags.GranFlags.Costs.gunblocktime +
2211 RtsFlags.GranFlags.Costs.latency;
2212 new_event(tso_loc, CurrentProc, CurrentTime[CurrentProc],
2214 tso, node, (rtsSpark*)NULL);
2215 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
2218 /* the thread-queue-overhead is accounted for in either Resume or UnblockThread */
2220 fprintf(stderr," %s TSO %d (%p) [PE %d] (block_info.closure=%p) (next=%p) ,",
2221 (node_loc==tso_loc ? "Local" : "Global"),
2222 tso->id, tso, CurrentProc, tso->block_info.closure, tso->link));
2223 tso->block_info.closure = NULL;
2224 IF_DEBUG(scheduler,belch("-- Waking up thread %ld (%p)",
2228 static StgBlockingQueueElement *
2229 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
2231 StgBlockingQueueElement *next;
2233 switch (get_itbl(bqe)->type) {
2235 ASSERT(((StgTSO *)bqe)->why_blocked != NotBlocked);
2236 /* if it's a TSO just push it onto the run_queue */
2238 // ((StgTSO *)bqe)->link = END_TSO_QUEUE; // debugging?
2239 PUSH_ON_RUN_QUEUE((StgTSO *)bqe);
2241 unblockCount(bqe, node);
2242 /* reset blocking status after dumping event */
2243 ((StgTSO *)bqe)->why_blocked = NotBlocked;
2247 /* if it's a BLOCKED_FETCH put it on the PendingFetches list */
2249 bqe->link = PendingFetches;
2250 PendingFetches = bqe;
2254 /* can ignore this case in a non-debugging setup;
2255 see comments on RBHSave closures above */
2257 /* check that the closure is an RBHSave closure */
2258 ASSERT(get_itbl((StgClosure *)bqe) == &stg_RBH_Save_0_info ||
2259 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_1_info ||
2260 get_itbl((StgClosure *)bqe) == &stg_RBH_Save_2_info);
2264 barf("{unblockOneLocked}Daq Qagh: Unexpected IP (%#lx; %s) in blocking queue at %#lx\n",
2265 get_itbl((StgClosure *)bqe), info_type((StgClosure *)bqe),
2269 // IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
2273 #else /* !GRAN && !PAR */
2275 unblockOneLocked(StgTSO *tso)
2279 ASSERT(get_itbl(tso)->type == TSO);
2280 ASSERT(tso->why_blocked != NotBlocked);
2281 tso->why_blocked = NotBlocked;
2283 PUSH_ON_RUN_QUEUE(tso);
2285 IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
2290 #if defined(GRAN) || defined(PAR)
2291 inline StgBlockingQueueElement *
2292 unblockOne(StgBlockingQueueElement *bqe, StgClosure *node)
2294 ACQUIRE_LOCK(&sched_mutex);
2295 bqe = unblockOneLocked(bqe, node);
2296 RELEASE_LOCK(&sched_mutex);
2301 unblockOne(StgTSO *tso)
2303 ACQUIRE_LOCK(&sched_mutex);
2304 tso = unblockOneLocked(tso);
2305 RELEASE_LOCK(&sched_mutex);
2312 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2314 StgBlockingQueueElement *bqe;
2319 belch("## AwBQ for node %p on PE %d @ %ld by TSO %d (%p): ", \
2320 node, CurrentProc, CurrentTime[CurrentProc],
2321 CurrentTSO->id, CurrentTSO));
2323 node_loc = where_is(node);
2325 ASSERT(get_itbl(q)->type == TSO || // q is either a TSO or an RBHSave
2326 get_itbl(q)->type == CONSTR); // closure (type constructor)
2327 ASSERT(is_unique(node));
2329 /* FAKE FETCH: magically copy the node to the tso's proc;
2330 no Fetch necessary because in reality the node should not have been
2331 moved to the other PE in the first place
2333 if (CurrentProc!=node_loc) {
2335 belch("## node %p is on PE %d but CurrentProc is %d (TSO %d); assuming fake fetch and adjusting bitmask (old: %#x)",
2336 node, node_loc, CurrentProc, CurrentTSO->id,
2337 // CurrentTSO, where_is(CurrentTSO),
2338 node->header.gran.procs));
2339 node->header.gran.procs = (node->header.gran.procs) | PE_NUMBER(CurrentProc);
2341 belch("## new bitmask of node %p is %#x",
2342 node, node->header.gran.procs));
2343 if (RtsFlags.GranFlags.GranSimStats.Global) {
2344 globalGranStats.tot_fake_fetches++;
2349 // ToDo: check: ASSERT(CurrentProc==node_loc);
2350 while (get_itbl(bqe)->type==TSO) { // q != END_TSO_QUEUE) {
2353 bqe points to the current element in the queue
2354 next points to the next element in the queue
2356 //tso = (StgTSO *)bqe; // wastes an assignment to get the type right
2357 //tso_loc = where_is(tso);
2359 bqe = unblockOneLocked(bqe, node);
2362 /* if this is the BQ of an RBH, we have to put back the info ripped out of
2363 the closure to make room for the anchor of the BQ */
2364 if (bqe!=END_BQ_QUEUE) {
2365 ASSERT(get_itbl(node)->type == RBH && get_itbl(bqe)->type == CONSTR);
2367 ASSERT((info_ptr==&RBH_Save_0_info) ||
2368 (info_ptr==&RBH_Save_1_info) ||
2369 (info_ptr==&RBH_Save_2_info));
2371 /* cf. convertToRBH in RBH.c for writing the RBHSave closure */
2372 ((StgRBH *)node)->blocking_queue = (StgBlockingQueueElement *)((StgRBHSave *)bqe)->payload[0];
2373 ((StgRBH *)node)->mut_link = (StgMutClosure *)((StgRBHSave *)bqe)->payload[1];
2376 belch("## Filled in RBH_Save for %p (%s) at end of AwBQ",
2377 node, info_type(node)));
2380 /* statistics gathering */
2381 if (RtsFlags.GranFlags.GranSimStats.Global) {
2382 // globalGranStats.tot_bq_processing_time += bq_processing_time;
2383 globalGranStats.tot_bq_len += len; // total length of all bqs awakened
2384 // globalGranStats.tot_bq_len_local += len_local; // same for local TSOs only
2385 globalGranStats.tot_awbq++; // total no. of bqs awakened
2388 fprintf(stderr,"## BQ Stats of %p: [%d entries] %s\n",
2389 node, len, (bqe!=END_BQ_QUEUE) ? "RBH" : ""));
2393 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
2395 StgBlockingQueueElement *bqe, *next;
2397 ACQUIRE_LOCK(&sched_mutex);
2399 IF_PAR_DEBUG(verbose,
2400 belch("## AwBQ for node %p on [%x]: ",
2403 ASSERT(get_itbl(q)->type == TSO ||
2404 get_itbl(q)->type == BLOCKED_FETCH ||
2405 get_itbl(q)->type == CONSTR);
2408 while (get_itbl(bqe)->type==TSO ||
2409 get_itbl(bqe)->type==BLOCKED_FETCH) {
2410 bqe = unblockOneLocked(bqe, node);
2412 RELEASE_LOCK(&sched_mutex);
2415 #else /* !GRAN && !PAR */
2417 awakenBlockedQueue(StgTSO *tso)
2419 ACQUIRE_LOCK(&sched_mutex);
2420 while (tso != END_TSO_QUEUE) {
2421 tso = unblockOneLocked(tso);
2423 RELEASE_LOCK(&sched_mutex);
2427 //@node Exception Handling Routines, Debugging Routines, Blocking Queue Routines, Main scheduling code
2428 //@subsection Exception Handling Routines
2430 /* ---------------------------------------------------------------------------
2432 - usually called inside a signal handler so it mustn't do anything fancy.
2433 ------------------------------------------------------------------------ */
2436 interruptStgRts(void)
2442 /* -----------------------------------------------------------------------------
2445 This is for use when we raise an exception in another thread, which
2447 This has nothing to do with the UnblockThread event in GranSim. -- HWL
2448 -------------------------------------------------------------------------- */
2450 #if defined(GRAN) || defined(PAR)
2452 NB: only the type of the blocking queue is different in GranSim and GUM
2453 the operations on the queue-elements are the same
2454 long live polymorphism!
2457 unblockThread(StgTSO *tso)
2459 StgBlockingQueueElement *t, **last;
2461 ACQUIRE_LOCK(&sched_mutex);
2462 switch (tso->why_blocked) {
2465 return; /* not blocked */
2468 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
2470 StgBlockingQueueElement *last_tso = END_BQ_QUEUE;
2471 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
2473 last = (StgBlockingQueueElement **)&mvar->head;
2474 for (t = (StgBlockingQueueElement *)mvar->head;
2476 last = &t->link, last_tso = t, t = t->link) {
2477 if (t == (StgBlockingQueueElement *)tso) {
2478 *last = (StgBlockingQueueElement *)tso->link;
2479 if (mvar->tail == tso) {
2480 mvar->tail = (StgTSO *)last_tso;
2485 barf("unblockThread (MVAR): TSO not found");
2488 case BlockedOnBlackHole:
2489 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
2491 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
2493 last = &bq->blocking_queue;
2494 for (t = bq->blocking_queue;
2496 last = &t->link, t = t->link) {
2497 if (t == (StgBlockingQueueElement *)tso) {
2498 *last = (StgBlockingQueueElement *)tso->link;
2502 barf("unblockThread (BLACKHOLE): TSO not found");
2505 case BlockedOnException:
2507 StgTSO *target = tso->block_info.tso;
2509 ASSERT(get_itbl(target)->type == TSO);
2510 ASSERT(target->blocked_exceptions != NULL);
2512 last = (StgBlockingQueueElement **)&target->blocked_exceptions;
2513 for (t = (StgBlockingQueueElement *)target->blocked_exceptions;
2515 last = &t->link, t = t->link) {
2516 ASSERT(get_itbl(t)->type == TSO);
2517 if (t == (StgBlockingQueueElement *)tso) {
2518 *last = (StgBlockingQueueElement *)tso->link;
2522 barf("unblockThread (Exception): TSO not found");
2526 case BlockedOnWrite:
2528 StgBlockingQueueElement *prev = NULL;
2529 for (t = (StgBlockingQueueElement *)blocked_queue_hd; t != END_BQ_QUEUE;
2530 prev = t, t = t->link) {
2531 if (t == (StgBlockingQueueElement *)tso) {
2533 blocked_queue_hd = (StgTSO *)t->link;
2534 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
2535 blocked_queue_tl = END_TSO_QUEUE;
2538 prev->link = t->link;
2539 if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
2540 blocked_queue_tl = (StgTSO *)prev;
2546 barf("unblockThread (I/O): TSO not found");
2549 case BlockedOnDelay:
2551 StgBlockingQueueElement *prev = NULL;
2552 for (t = (StgBlockingQueueElement *)sleeping_queue; t != END_BQ_QUEUE;
2553 prev = t, t = t->link) {
2554 if (t == (StgBlockingQueueElement *)tso) {
2556 sleeping_queue = (StgTSO *)t->link;
2558 prev->link = t->link;
2563 barf("unblockThread (I/O): TSO not found");
2567 barf("unblockThread");
2571 tso->link = END_TSO_QUEUE;
2572 tso->why_blocked = NotBlocked;
2573 tso->block_info.closure = NULL;
2574 PUSH_ON_RUN_QUEUE(tso);
2575 RELEASE_LOCK(&sched_mutex);
2579 unblockThread(StgTSO *tso)
2583 ACQUIRE_LOCK(&sched_mutex);
2584 switch (tso->why_blocked) {
2587 return; /* not blocked */
2590 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
2592 StgTSO *last_tso = END_TSO_QUEUE;
2593 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
2596 for (t = mvar->head; t != END_TSO_QUEUE;
2597 last = &t->link, last_tso = t, t = t->link) {
2600 if (mvar->tail == tso) {
2601 mvar->tail = last_tso;
2606 barf("unblockThread (MVAR): TSO not found");
2609 case BlockedOnBlackHole:
2610 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
2612 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
2614 last = &bq->blocking_queue;
2615 for (t = bq->blocking_queue; t != END_TSO_QUEUE;
2616 last = &t->link, t = t->link) {
2622 barf("unblockThread (BLACKHOLE): TSO not found");
2625 case BlockedOnException:
2627 StgTSO *target = tso->block_info.tso;
2629 ASSERT(get_itbl(target)->type == TSO);
2630 ASSERT(target->blocked_exceptions != NULL);
2632 last = &target->blocked_exceptions;
2633 for (t = target->blocked_exceptions; t != END_TSO_QUEUE;
2634 last = &t->link, t = t->link) {
2635 ASSERT(get_itbl(t)->type == TSO);
2641 barf("unblockThread (Exception): TSO not found");
2645 case BlockedOnWrite:
2647 StgTSO *prev = NULL;
2648 for (t = blocked_queue_hd; t != END_TSO_QUEUE;
2649 prev = t, t = t->link) {
2652 blocked_queue_hd = t->link;
2653 if (blocked_queue_tl == t) {
2654 blocked_queue_tl = END_TSO_QUEUE;
2657 prev->link = t->link;
2658 if (blocked_queue_tl == t) {
2659 blocked_queue_tl = prev;
2665 barf("unblockThread (I/O): TSO not found");
2668 case BlockedOnDelay:
2670 StgTSO *prev = NULL;
2671 for (t = sleeping_queue; t != END_TSO_QUEUE;
2672 prev = t, t = t->link) {
2675 sleeping_queue = t->link;
2677 prev->link = t->link;
2682 barf("unblockThread (I/O): TSO not found");
2686 barf("unblockThread");
2690 tso->link = END_TSO_QUEUE;
2691 tso->why_blocked = NotBlocked;
2692 tso->block_info.closure = NULL;
2693 PUSH_ON_RUN_QUEUE(tso);
2694 RELEASE_LOCK(&sched_mutex);
2698 /* -----------------------------------------------------------------------------
2701 * The following function implements the magic for raising an
2702 * asynchronous exception in an existing thread.
2704 * We first remove the thread from any queue on which it might be
2705 * blocked. The possible blockages are MVARs and BLACKHOLE_BQs.
2707 * We strip the stack down to the innermost CATCH_FRAME, building
2708 * thunks in the heap for all the active computations, so they can
2709 * be restarted if necessary. When we reach a CATCH_FRAME, we build
2710 * an application of the handler to the exception, and push it on
2711 * the top of the stack.
2713 * How exactly do we save all the active computations? We create an
2714 * AP_UPD for every UpdateFrame on the stack. Entering one of these
2715 * AP_UPDs pushes everything from the corresponding update frame
2716 * upwards onto the stack. (Actually, it pushes everything up to the
2717 * next update frame plus a pointer to the next AP_UPD object.
2718 * Entering the next AP_UPD object pushes more onto the stack until we
2719 * reach the last AP_UPD object - at which point the stack should look
2720 * exactly as it did when we killed the TSO and we can continue
2721 * execution by entering the closure on top of the stack.
2723 * We can also kill a thread entirely - this happens if either (a) the
2724 * exception passed to raiseAsync is NULL, or (b) there's no
2725 * CATCH_FRAME on the stack. In either case, we strip the entire
2726 * stack and replace the thread with a zombie.
2728 * -------------------------------------------------------------------------- */
2731 deleteThread(StgTSO *tso)
2733 raiseAsync(tso,NULL);
2737 raiseAsync(StgTSO *tso, StgClosure *exception)
2739 StgUpdateFrame* su = tso->su;
2740 StgPtr sp = tso->sp;
2742 /* Thread already dead? */
2743 if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) {
2747 IF_DEBUG(scheduler, sched_belch("raising exception in thread %ld.", tso->id));
2749 /* Remove it from any blocking queues */
2752 /* The stack freezing code assumes there's a closure pointer on
2753 * the top of the stack. This isn't always the case with compiled
2754 * code, so we have to push a dummy closure on the top which just
2755 * returns to the next return address on the stack.
2757 if ( LOOKS_LIKE_GHC_INFO((void*)*sp) ) {
2758 *(--sp) = (W_)&stg_dummy_ret_closure;
2762 int words = ((P_)su - (P_)sp) - 1;
2766 /* If we find a CATCH_FRAME, and we've got an exception to raise,
2767 * then build PAP(handler,exception,realworld#), and leave it on
2768 * top of the stack ready to enter.
2770 if (get_itbl(su)->type == CATCH_FRAME && exception != NULL) {
2771 StgCatchFrame *cf = (StgCatchFrame *)su;
2772 /* we've got an exception to raise, so let's pass it to the
2773 * handler in this frame.
2775 ap = (StgAP_UPD *)allocate(sizeofW(StgPAP) + 2);
2776 TICK_ALLOC_UPD_PAP(3,0);
2777 SET_HDR(ap,&stg_PAP_info,cf->header.prof.ccs);
2780 ap->fun = cf->handler; /* :: Exception -> IO a */
2781 ap->payload[0] = exception;
2782 ap->payload[1] = ARG_TAG(0); /* realworld token */
2784 /* throw away the stack from Sp up to and including the
2787 sp = (P_)su + sizeofW(StgCatchFrame) - 1;
2790 /* Restore the blocked/unblocked state for asynchronous exceptions
2791 * at the CATCH_FRAME.
2793 * If exceptions were unblocked at the catch, arrange that they
2794 * are unblocked again after executing the handler by pushing an
2795 * unblockAsyncExceptions_ret stack frame.
2797 if (!cf->exceptions_blocked) {
2798 *(sp--) = (W_)&stg_unblockAsyncExceptionszh_ret_info;
2801 /* Ensure that async exceptions are blocked when running the handler.
2803 if (tso->blocked_exceptions == NULL) {
2804 tso->blocked_exceptions = END_TSO_QUEUE;
2807 /* Put the newly-built PAP on top of the stack, ready to execute
2808 * when the thread restarts.
2812 tso->what_next = ThreadEnterGHC;
2813 IF_DEBUG(sanity, checkTSO(tso));
2817 /* First build an AP_UPD consisting of the stack chunk above the
2818 * current update frame, with the top word on the stack as the
2821 ap = (StgAP_UPD *)allocate(AP_sizeW(words));
2826 ap->fun = (StgClosure *)sp[0];
2828 for(i=0; i < (nat)words; ++i) {
2829 ap->payload[i] = (StgClosure *)*sp++;
2832 switch (get_itbl(su)->type) {
2836 SET_HDR(ap,&stg_AP_UPD_info,su->header.prof.ccs /* ToDo */);
2837 TICK_ALLOC_UP_THK(words+1,0);
2840 fprintf(stderr, "scheduler: Updating ");
2841 printPtr((P_)su->updatee);
2842 fprintf(stderr, " with ");
2843 printObj((StgClosure *)ap);
2846 /* Replace the updatee with an indirection - happily
2847 * this will also wake up any threads currently
2848 * waiting on the result.
2850 UPD_IND_NOLOCK(su->updatee,ap); /* revert the black hole */
2852 sp += sizeofW(StgUpdateFrame) -1;
2853 sp[0] = (W_)ap; /* push onto stack */
2859 StgCatchFrame *cf = (StgCatchFrame *)su;
2862 /* We want a PAP, not an AP_UPD. Fortunately, the
2863 * layout's the same.
2865 SET_HDR(ap,&stg_PAP_info,su->header.prof.ccs /* ToDo */);
2866 TICK_ALLOC_UPD_PAP(words+1,0);
2868 /* now build o = FUN(catch,ap,handler) */
2869 o = (StgClosure *)allocate(sizeofW(StgClosure)+2);
2870 TICK_ALLOC_FUN(2,0);
2871 SET_HDR(o,&stg_catch_info,su->header.prof.ccs /* ToDo */);
2872 o->payload[0] = (StgClosure *)ap;
2873 o->payload[1] = cf->handler;
2876 fprintf(stderr, "scheduler: Built ");
2877 printObj((StgClosure *)o);
2880 /* pop the old handler and put o on the stack */
2882 sp += sizeofW(StgCatchFrame) - 1;
2889 StgSeqFrame *sf = (StgSeqFrame *)su;
2892 SET_HDR(ap,&stg_PAP_info,su->header.prof.ccs /* ToDo */);
2893 TICK_ALLOC_UPD_PAP(words+1,0);
2895 /* now build o = FUN(seq,ap) */
2896 o = (StgClosure *)allocate(sizeofW(StgClosure)+1);
2897 TICK_ALLOC_SE_THK(1,0);
2898 SET_HDR(o,&stg_seq_info,su->header.prof.ccs /* ToDo */);
2899 o->payload[0] = (StgClosure *)ap;
2902 fprintf(stderr, "scheduler: Built ");
2903 printObj((StgClosure *)o);
2906 /* pop the old handler and put o on the stack */
2908 sp += sizeofW(StgSeqFrame) - 1;
2914 /* We've stripped the entire stack, the thread is now dead. */
2915 sp += sizeofW(StgStopFrame) - 1;
2916 sp[0] = (W_)exception; /* save the exception */
2917 tso->what_next = ThreadKilled;
2918 tso->su = (StgUpdateFrame *)(sp+1);
2929 /* -----------------------------------------------------------------------------
2930 resurrectThreads is called after garbage collection on the list of
2931 threads found to be garbage. Each of these threads will be woken
2932 up and sent a signal: BlockedOnDeadMVar if the thread was blocked
2933 on an MVar, or NonTermination if the thread was blocked on a Black
2935 -------------------------------------------------------------------------- */
2938 resurrectThreads( StgTSO *threads )
2942 for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
2943 next = tso->global_link;
2944 tso->global_link = all_threads;
2946 IF_DEBUG(scheduler, sched_belch("resurrecting thread %d", tso->id));
2948 switch (tso->why_blocked) {
2950 case BlockedOnException:
2951 raiseAsync(tso,(StgClosure *)BlockedOnDeadMVar_closure);
2953 case BlockedOnBlackHole:
2954 raiseAsync(tso,(StgClosure *)NonTermination_closure);
2957 /* This might happen if the thread was blocked on a black hole
2958 * belonging to a thread that we've just woken up (raiseAsync
2959 * can wake up threads, remember...).
2963 barf("resurrectThreads: thread blocked in a strange way");
2968 /* -----------------------------------------------------------------------------
2969 * Blackhole detection: if we reach a deadlock, test whether any
2970 * threads are blocked on themselves. Any threads which are found to
2971 * be self-blocked get sent a NonTermination exception.
2973 * This is only done in a deadlock situation in order to avoid
2974 * performance overhead in the normal case.
2975 * -------------------------------------------------------------------------- */
2978 detectBlackHoles( void )
2980 StgTSO *t = all_threads;
2981 StgUpdateFrame *frame;
2982 StgClosure *blocked_on;
2984 for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
2986 if (t->why_blocked != BlockedOnBlackHole) {
2990 blocked_on = t->block_info.closure;
2992 for (frame = t->su; ; frame = frame->link) {
2993 switch (get_itbl(frame)->type) {
2996 if (frame->updatee == blocked_on) {
2997 /* We are blocking on one of our own computations, so
2998 * send this thread the NonTermination exception.
3001 sched_belch("thread %d is blocked on itself", t->id));
3002 raiseAsync(t, (StgClosure *)NonTermination_closure);
3023 //@node Debugging Routines, Index, Exception Handling Routines, Main scheduling code
3024 //@subsection Debugging Routines
3026 /* -----------------------------------------------------------------------------
3027 Debugging: why is a thread blocked
3028 -------------------------------------------------------------------------- */
3033 printThreadBlockage(StgTSO *tso)
3035 switch (tso->why_blocked) {
3037 fprintf(stderr,"is blocked on read from fd %d", tso->block_info.fd);
3039 case BlockedOnWrite:
3040 fprintf(stderr,"is blocked on write to fd %d", tso->block_info.fd);
3042 case BlockedOnDelay:
3043 fprintf(stderr,"is blocked until %d", tso->block_info.target);
3046 fprintf(stderr,"is blocked on an MVar");
3048 case BlockedOnException:
3049 fprintf(stderr,"is blocked on delivering an exception to thread %d",
3050 tso->block_info.tso->id);
3052 case BlockedOnBlackHole:
3053 fprintf(stderr,"is blocked on a black hole");
3056 fprintf(stderr,"is not blocked");
3060 fprintf(stderr,"is blocked on global address; local FM_BQ is %p (%s)",
3061 tso->block_info.closure, info_type(tso->block_info.closure));
3063 case BlockedOnGA_NoSend:
3064 fprintf(stderr,"is blocked on global address (no send); local FM_BQ is %p (%s)",
3065 tso->block_info.closure, info_type(tso->block_info.closure));
3069 barf("printThreadBlockage: strange tso->why_blocked: %d for TSO %d (%d)",
3070 tso->why_blocked, tso->id, tso);
3075 printThreadStatus(StgTSO *tso)
3077 switch (tso->what_next) {
3079 fprintf(stderr,"has been killed");
3081 case ThreadComplete:
3082 fprintf(stderr,"has completed");
3085 printThreadBlockage(tso);
3090 printAllThreads(void)
3094 sched_belch("all threads:");
3095 for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
3096 fprintf(stderr, "\tthread %d ", t->id);
3097 printThreadStatus(t);
3098 fprintf(stderr,"\n");
3103 Print a whole blocking queue attached to node (debugging only).
3108 print_bq (StgClosure *node)
3110 StgBlockingQueueElement *bqe;
3114 fprintf(stderr,"## BQ of closure %p (%s): ",
3115 node, info_type(node));
3117 /* should cover all closures that may have a blocking queue */
3118 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3119 get_itbl(node)->type == FETCH_ME_BQ ||
3120 get_itbl(node)->type == RBH);
3122 ASSERT(node!=(StgClosure*)NULL); // sanity check
3124 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3126 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
3127 !end; // iterate until bqe points to a CONSTR
3128 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
3129 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3130 ASSERT(bqe != (StgTSO*)NULL); // sanity check
3131 /* types of closures that may appear in a blocking queue */
3132 ASSERT(get_itbl(bqe)->type == TSO ||
3133 get_itbl(bqe)->type == BLOCKED_FETCH ||
3134 get_itbl(bqe)->type == CONSTR);
3135 /* only BQs of an RBH end with an RBH_Save closure */
3136 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3138 switch (get_itbl(bqe)->type) {
3140 fprintf(stderr," TSO %d (%x),",
3141 ((StgTSO *)bqe)->id, ((StgTSO *)bqe));
3144 fprintf(stderr," BF (node=%p, ga=((%x, %d, %x)),",
3145 ((StgBlockedFetch *)bqe)->node,
3146 ((StgBlockedFetch *)bqe)->ga.payload.gc.gtid,
3147 ((StgBlockedFetch *)bqe)->ga.payload.gc.slot,
3148 ((StgBlockedFetch *)bqe)->ga.weight);
3151 fprintf(stderr," %s (IP %p),",
3152 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3153 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3154 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3155 "RBH_Save_?"), get_itbl(bqe));
3158 barf("Unexpected closure type %s in blocking queue of %p (%s)",
3159 info_type(bqe), node, info_type(node));
3163 fputc('\n', stderr);
3165 # elif defined(GRAN)
3167 print_bq (StgClosure *node)
3169 StgBlockingQueueElement *bqe;
3170 PEs node_loc, tso_loc;
3173 /* should cover all closures that may have a blocking queue */
3174 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
3175 get_itbl(node)->type == FETCH_ME_BQ ||
3176 get_itbl(node)->type == RBH);
3178 ASSERT(node!=(StgClosure*)NULL); // sanity check
3179 node_loc = where_is(node);
3181 fprintf(stderr,"## BQ of closure %p (%s) on [PE %d]: ",
3182 node, info_type(node), node_loc);
3185 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
3187 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
3188 !end; // iterate until bqe points to a CONSTR
3189 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
3190 ASSERT(bqe != END_BQ_QUEUE); // sanity check
3191 ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
3192 /* types of closures that may appear in a blocking queue */
3193 ASSERT(get_itbl(bqe)->type == TSO ||
3194 get_itbl(bqe)->type == CONSTR);
3195 /* only BQs of an RBH end with an RBH_Save closure */
3196 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
3198 tso_loc = where_is((StgClosure *)bqe);
3199 switch (get_itbl(bqe)->type) {
3201 fprintf(stderr," TSO %d (%p) on [PE %d],",
3202 ((StgTSO *)bqe)->id, (StgTSO *)bqe, tso_loc);
3205 fprintf(stderr," %s (IP %p),",
3206 (get_itbl(bqe) == &stg_RBH_Save_0_info ? "RBH_Save_0" :
3207 get_itbl(bqe) == &stg_RBH_Save_1_info ? "RBH_Save_1" :
3208 get_itbl(bqe) == &stg_RBH_Save_2_info ? "RBH_Save_2" :
3209 "RBH_Save_?"), get_itbl(bqe));
3212 barf("Unexpected closure type %s in blocking queue of %p (%s)",
3213 info_type((StgClosure *)bqe), node, info_type(node));
3217 fputc('\n', stderr);
3221 Nice and easy: only TSOs on the blocking queue
3224 print_bq (StgClosure *node)
3228 ASSERT(node!=(StgClosure*)NULL); // sanity check
3229 for (tso = ((StgBlockingQueue*)node)->blocking_queue;
3230 tso != END_TSO_QUEUE;
3232 ASSERT(tso!=NULL && tso!=END_TSO_QUEUE); // sanity check
3233 ASSERT(get_itbl(tso)->type == TSO); // guess what, sanity check
3234 fprintf(stderr," TSO %d (%p),", tso->id, tso);
3236 fputc('\n', stderr);
3247 for (i=0, tso=run_queue_hd;
3248 tso != END_TSO_QUEUE;
3257 sched_belch(char *s, ...)
3262 fprintf(stderr, "scheduler (task %ld): ", pthread_self());
3264 fprintf(stderr, "scheduler: ");
3266 vfprintf(stderr, s, ap);
3267 fprintf(stderr, "\n");
3273 //@node Index, , Debugging Routines, Main scheduling code
3277 //* MainRegTable:: @cindex\s-+MainRegTable
3278 //* StgMainThread:: @cindex\s-+StgMainThread
3279 //* awaken_blocked_queue:: @cindex\s-+awaken_blocked_queue
3280 //* blocked_queue_hd:: @cindex\s-+blocked_queue_hd
3281 //* blocked_queue_tl:: @cindex\s-+blocked_queue_tl
3282 //* context_switch:: @cindex\s-+context_switch
3283 //* createThread:: @cindex\s-+createThread
3284 //* free_capabilities:: @cindex\s-+free_capabilities
3285 //* gc_pending_cond:: @cindex\s-+gc_pending_cond
3286 //* initScheduler:: @cindex\s-+initScheduler
3287 //* interrupted:: @cindex\s-+interrupted
3288 //* n_free_capabilities:: @cindex\s-+n_free_capabilities
3289 //* next_thread_id:: @cindex\s-+next_thread_id
3290 //* print_bq:: @cindex\s-+print_bq
3291 //* run_queue_hd:: @cindex\s-+run_queue_hd
3292 //* run_queue_tl:: @cindex\s-+run_queue_tl
3293 //* sched_mutex:: @cindex\s-+sched_mutex
3294 //* schedule:: @cindex\s-+schedule
3295 //* take_off_run_queue:: @cindex\s-+take_off_run_queue
3296 //* task_ids:: @cindex\s-+task_ids
3297 //* term_mutex:: @cindex\s-+term_mutex
3298 //* thread_ready_cond:: @cindex\s-+thread_ready_cond