1 /* ---------------------------------------------------------------------------
2 * $Id: Schedule.c,v 1.44 2000/01/14 13:39:59 simonmar Exp $
4 * (c) The GHC Team, 1998-1999
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::
41 //* Main scheduling loop::
42 //* Suspend and Resume::
44 //* Garbage Collextion Routines::
45 //* Blocking Queue Routines::
46 //* Exception Handling Routines::
47 //* Debugging Routines::
51 //@node Includes, Variables and Data structures, Main scheduling code, Main scheduling code
52 //@subsection Includes
60 #include "StgStartup.h"
64 #include "StgMiscClosures.h"
66 #include "Evaluator.h"
67 #include "Exception.h"
71 #include "Profiling.h"
75 #if defined(GRAN) || defined(PAR)
76 # include "GranSimRts.h"
78 # include "ParallelRts.h"
79 # include "Parallel.h"
80 # 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.
126 StgTSO* ActiveTSO = NULL; /* for assigning system costs; GranSim-Light only */
127 /* rtsTime TimeOfNextEvent, EndOfTimeSlice; now in GranSim.c */
130 In GranSim we have a runable and a blocked queue for each processor.
131 In order to minimise code changes new arrays run_queue_hds/tls
132 are created. run_queue_hd is then a short cut (macro) for
133 run_queue_hds[CurrentProc] (see GranSim.h).
136 StgTSO *run_queue_hds[MAX_PROC], *run_queue_tls[MAX_PROC];
137 StgTSO *blocked_queue_hds[MAX_PROC], *blocked_queue_tls[MAX_PROC];
138 StgTSO *ccalling_threadss[MAX_PROC];
142 //@cindex run_queue_hd
143 //@cindex run_queue_tl
144 //@cindex blocked_queue_hd
145 //@cindex blocked_queue_tl
146 StgTSO *run_queue_hd, *run_queue_tl;
147 StgTSO *blocked_queue_hd, *blocked_queue_tl;
149 /* Threads suspended in _ccall_GC.
150 * Locks required: sched_mutex.
152 static StgTSO *suspended_ccalling_threads;
154 static void GetRoots(void);
155 static StgTSO *threadStackOverflow(StgTSO *tso);
158 /* KH: The following two flags are shared memory locations. There is no need
159 to lock them, since they are only unset at the end of a scheduler
163 /* flag set by signal handler to precipitate a context switch */
164 //@cindex context_switch
167 /* if this flag is set as well, give up execution */
168 //@cindex interrupted
171 /* Next thread ID to allocate.
172 * Locks required: sched_mutex
174 //@cindex next_thread_id
175 StgThreadID next_thread_id = 1;
178 * Pointers to the state of the current thread.
179 * Rule of thumb: if CurrentTSO != NULL, then we're running a Haskell
180 * thread. If CurrentTSO == NULL, then we're at the scheduler level.
183 /* The smallest stack size that makes any sense is:
184 * RESERVED_STACK_WORDS (so we can get back from the stack overflow)
185 * + sizeofW(StgStopFrame) (the stg_stop_thread_info frame)
186 * + 1 (the realworld token for an IO thread)
187 * + 1 (the closure to enter)
189 * A thread with this stack will bomb immediately with a stack
190 * overflow, which will increase its stack size.
193 #define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 2)
195 /* Free capability list.
196 * Locks required: sched_mutex.
199 //@cindex free_capabilities
200 //@cindex n_free_capabilities
201 Capability *free_capabilities; /* Available capabilities for running threads */
202 nat n_free_capabilities; /* total number of available capabilities */
204 //@cindex MainRegTable
205 Capability MainRegTable; /* for non-SMP, we have one global capability */
209 StgTSO *CurrentTSOs[MAX_PROC];
216 /* All our current task ids, saved in case we need to kill them later.
223 void addToBlockedQueue ( StgTSO *tso );
225 static void schedule ( void );
226 void interruptStgRts ( void );
227 static StgTSO * createThread_ ( nat size, rtsBool have_lock );
230 static void sched_belch(char *s, ...);
234 //@cindex sched_mutex
236 //@cindex thread_ready_cond
237 //@cindex gc_pending_cond
238 pthread_mutex_t sched_mutex = PTHREAD_MUTEX_INITIALIZER;
239 pthread_mutex_t term_mutex = PTHREAD_MUTEX_INITIALIZER;
240 pthread_cond_t thread_ready_cond = PTHREAD_COND_INITIALIZER;
241 pthread_cond_t gc_pending_cond = PTHREAD_COND_INITIALIZER;
248 rtsTime TimeOfLastYield;
252 * The thread state for the main thread.
253 // ToDo: check whether not needed any more
258 //@node Prototypes, Main scheduling loop, Variables and Data structures, Main scheduling code
259 //@subsection Prototypes
261 //@node Main scheduling loop, Suspend and Resume, Prototypes, Main scheduling code
262 //@subsection Main scheduling loop
264 /* ---------------------------------------------------------------------------
265 Main scheduling loop.
267 We use round-robin scheduling, each thread returning to the
268 scheduler loop when one of these conditions is detected:
271 * timer expires (thread yields)
276 Locking notes: we acquire the scheduler lock once at the beginning
277 of the scheduler loop, and release it when
279 * running a thread, or
280 * waiting for work, or
281 * waiting for a GC to complete.
283 ------------------------------------------------------------------------ */
290 StgThreadReturnCode ret;
299 ACQUIRE_LOCK(&sched_mutex);
302 # error ToDo: implement GranSim scheduler
304 while (!GlobalStopPending) { /* GlobalStopPending set in par_exit */
306 if (PendingFetches != END_BF_QUEUE) {
313 /* If we're interrupted (the user pressed ^C, or some other
314 * termination condition occurred), kill all the currently running
318 IF_DEBUG(scheduler, sched_belch("interrupted"));
319 for (t = run_queue_hd; t != END_TSO_QUEUE; t = t->link) {
322 for (t = blocked_queue_hd; t != END_TSO_QUEUE; t = t->link) {
325 run_queue_hd = run_queue_tl = END_TSO_QUEUE;
326 blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
329 /* Go through the list of main threads and wake up any
330 * clients whose computations have finished. ToDo: this
331 * should be done more efficiently without a linear scan
332 * of the main threads list, somehow...
336 StgMainThread *m, **prev;
337 prev = &main_threads;
338 for (m = main_threads; m != NULL; m = m->link) {
339 switch (m->tso->whatNext) {
342 *(m->ret) = (StgClosure *)m->tso->sp[0];
346 pthread_cond_broadcast(&m->wakeup);
351 pthread_cond_broadcast(&m->wakeup);
359 /* If our main thread has finished or been killed, return.
362 StgMainThread *m = main_threads;
363 if (m->tso->whatNext == ThreadComplete
364 || m->tso->whatNext == ThreadKilled) {
365 main_threads = main_threads->link;
366 if (m->tso->whatNext == ThreadComplete) {
367 /* we finished successfully, fill in the return value */
368 if (m->ret) { *(m->ret) = (StgClosure *)m->tso->sp[0]; };
379 /* Top up the run queue from our spark pool. We try to make the
380 * number of threads in the run queue equal to the number of
385 nat n = n_free_capabilities;
386 StgTSO *tso = run_queue_hd;
388 /* Count the run queue */
389 while (n > 0 && tso != END_TSO_QUEUE) {
398 break; /* no more sparks in the pool */
400 /* I'd prefer this to be done in activateSpark -- HWL */
401 /* tricky - it needs to hold the scheduler lock and
402 * not try to re-acquire it -- SDM */
404 tso = createThread_(RtsFlags.GcFlags.initialStkSize, rtsTrue);
405 pushClosure(tso,spark);
406 PUSH_ON_RUN_QUEUE(tso);
408 advisory_thread_count++;
412 sched_belch("turning spark of closure %p into a thread",
413 (StgClosure *)spark));
416 /* We need to wake up the other tasks if we just created some
419 if (n_free_capabilities - n > 1) {
420 pthread_cond_signal(&thread_ready_cond);
425 /* Check whether any waiting threads need to be woken up. If the
426 * run queue is empty, and there are no other tasks running, we
427 * can wait indefinitely for something to happen.
428 * ToDo: what if another client comes along & requests another
431 if (blocked_queue_hd != END_TSO_QUEUE) {
433 (run_queue_hd == END_TSO_QUEUE)
435 && (n_free_capabilities == RtsFlags.ParFlags.nNodes)
440 /* check for signals each time around the scheduler */
442 if (signals_pending()) {
443 start_signal_handlers();
447 /* Detect deadlock: when we have no threads to run, there are
448 * no threads waiting on I/O or sleeping, and all the other
449 * tasks are waiting for work, we must have a deadlock. Inform
450 * all the main threads.
453 if (blocked_queue_hd == END_TSO_QUEUE
454 && run_queue_hd == END_TSO_QUEUE
455 && (n_free_capabilities == RtsFlags.ParFlags.nNodes)
458 for (m = main_threads; m != NULL; m = m->link) {
461 pthread_cond_broadcast(&m->wakeup);
466 if (blocked_queue_hd == END_TSO_QUEUE
467 && run_queue_hd == END_TSO_QUEUE) {
468 StgMainThread *m = main_threads;
471 main_threads = m->link;
477 /* If there's a GC pending, don't do anything until it has
481 IF_DEBUG(scheduler,sched_belch("waiting for GC"));
482 pthread_cond_wait(&gc_pending_cond, &sched_mutex);
485 /* block until we've got a thread on the run queue and a free
488 while (run_queue_hd == END_TSO_QUEUE || free_capabilities == NULL) {
489 IF_DEBUG(scheduler, sched_belch("waiting for work"));
490 pthread_cond_wait(&thread_ready_cond, &sched_mutex);
491 IF_DEBUG(scheduler, sched_belch("work now available"));
496 # error ToDo: implement GranSim scheduler
498 /* ToDo: phps merge with spark activation above */
499 /* check whether we have local work and send requests if we have none */
500 if (run_queue_hd == END_TSO_QUEUE) { /* no runnable threads */
501 /* :-[ no local threads => look out for local sparks */
502 if (advisory_thread_count < RtsFlags.ParFlags.maxThreads &&
503 (pending_sparks_hd[REQUIRED_POOL] < pending_sparks_tl[REQUIRED_POOL] ||
504 pending_sparks_hd[ADVISORY_POOL] < pending_sparks_tl[ADVISORY_POOL])) {
506 * ToDo: add GC code check that we really have enough heap afterwards!!
508 * If we're here (no runnable threads) and we have pending
509 * sparks, we must have a space problem. Get enough space
510 * to turn one of those pending sparks into a
514 spark = findSpark(); /* get a spark */
515 if (spark != (rtsSpark) NULL) {
516 tso = activateSpark(spark); /* turn the spark into a thread */
517 IF_PAR_DEBUG(verbose,
518 belch("== [%x] schedule: Created TSO %p (%d); %d threads active",
519 mytid, tso, tso->id, advisory_thread_count));
521 if (tso==END_TSO_QUEUE) { /* failed to activate spark->back to loop */
522 belch("^^ failed to activate spark");
524 } /* otherwise fall through & pick-up new tso */
526 IF_PAR_DEBUG(verbose,
527 belch("^^ no local sparks (spark pool contains only NFs: %d)",
528 spark_queue_len(ADVISORY_POOL)));
532 /* =8-[ no local sparks => look for work on other PEs */
535 * We really have absolutely no work. Send out a fish
536 * (there may be some out there already), and wait for
537 * something to arrive. We clearly can't run any threads
538 * until a SCHEDULE or RESUME arrives, and so that's what
539 * we're hoping to see. (Of course, we still have to
540 * respond to other types of messages.)
543 outstandingFishes < RtsFlags.ParFlags.maxFishes ) { // &&
544 // (last_fish_arrived_at+FISH_DELAY < CURRENT_TIME)) {
545 /* fishing set in sendFish, processFish;
546 avoid flooding system with fishes via delay */
548 sendFish(pe, mytid, NEW_FISH_AGE, NEW_FISH_HISTORY,
556 } else if (PacketsWaiting()) { /* Look for incoming messages */
560 /* Now we are sure that we have some work available */
561 ASSERT(run_queue_hd != END_TSO_QUEUE);
562 /* Take a thread from the run queue, if we have work */
563 t = take_off_run_queue(END_TSO_QUEUE);
565 /* ToDo: write something to the log-file
566 if (RTSflags.ParFlags.granSimStats && !sameThread)
567 DumpGranEvent(GR_SCHEDULE, RunnableThreadsHd);
572 IF_DEBUG(scheduler, belch("--^^ %d sparks on [%#x] (hd=%x; tl=%x; lim=%x)",
573 spark_queue_len(ADVISORY_POOL), CURRENT_PROC,
574 pending_sparks_hd[ADVISORY_POOL],
575 pending_sparks_tl[ADVISORY_POOL],
576 pending_sparks_lim[ADVISORY_POOL]));
578 IF_DEBUG(scheduler, belch("--== %d threads on [%#x] (hd=%x; tl=%x)",
579 run_queue_len(), CURRENT_PROC,
580 run_queue_hd, run_queue_tl));
584 we are running a different TSO, so write a schedule event to log file
585 NB: If we use fair scheduling we also have to write a deschedule
586 event for LastTSO; with unfair scheduling we know that the
587 previous tso has blocked whenever we switch to another tso, so
588 we don't need it in GUM for now
590 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
591 GR_SCHEDULE, t, (StgClosure *)NULL, 0, 0);
595 #else /* !GRAN && !PAR */
597 /* grab a thread from the run queue
606 cap = free_capabilities;
607 free_capabilities = cap->link;
608 n_free_capabilities--;
613 cap->rCurrentTSO = t;
615 /* set the context_switch flag
617 if (run_queue_hd == END_TSO_QUEUE)
622 RELEASE_LOCK(&sched_mutex);
624 IF_DEBUG(scheduler,sched_belch("running thread %d", t->id));
626 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
627 /* Run the current thread
629 switch (cap->rCurrentTSO->whatNext) {
632 /* Thread already finished, return to scheduler. */
633 ret = ThreadFinished;
636 ret = StgRun((StgFunPtr) stg_enterStackTop, cap);
639 ret = StgRun((StgFunPtr) stg_returnToStackTop, cap);
641 case ThreadEnterHugs:
645 IF_DEBUG(scheduler,sched_belch("entering Hugs"));
646 c = (StgClosure *)(cap->rCurrentTSO->sp[0]);
647 cap->rCurrentTSO->sp += 1;
652 barf("Panic: entered a BCO but no bytecode interpreter in this build");
655 barf("schedule: invalid whatNext field");
657 /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
659 /* Costs for the scheduler are assigned to CCS_SYSTEM */
664 ACQUIRE_LOCK(&sched_mutex);
667 IF_DEBUG(scheduler,fprintf(stderr,"scheduler (task %ld): ", pthread_self()););
669 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: "););
671 t = cap->rCurrentTSO;
675 /* make all the running tasks block on a condition variable,
676 * maybe set context_switch and wait till they all pile in,
677 * then have them wait on a GC condition variable.
679 IF_DEBUG(scheduler,belch("thread %ld stopped: HeapOverflow", t->id));
682 ready_to_gc = rtsTrue;
683 context_switch = 1; /* stop other threads ASAP */
684 PUSH_ON_RUN_QUEUE(t);
688 /* just adjust the stack for this thread, then pop it back
691 IF_DEBUG(scheduler,belch("thread %ld stopped, StackOverflow", t->id));
695 /* enlarge the stack */
696 StgTSO *new_t = threadStackOverflow(t);
698 /* This TSO has moved, so update any pointers to it from the
699 * main thread stack. It better not be on any other queues...
702 for (m = main_threads; m != NULL; m = m->link) {
707 PUSH_ON_RUN_QUEUE(new_t);
714 DumpGranEvent(GR_DESCHEDULE, t));
715 globalGranStats.tot_yields++;
718 DumpGranEvent(GR_DESCHEDULE, t));
720 /* put the thread back on the run queue. Then, if we're ready to
721 * GC, check whether this is the last task to stop. If so, wake
722 * up the GC thread. getThread will block during a GC until the
726 if (t->whatNext == ThreadEnterHugs) {
727 /* ToDo: or maybe a timer expired when we were in Hugs?
728 * or maybe someone hit ctrl-C
730 belch("thread %ld stopped to switch to Hugs", t->id);
732 belch("thread %ld stopped, yielding", t->id);
736 APPEND_TO_RUN_QUEUE(t);
741 # error ToDo: implement GranSim scheduler
744 DumpGranEvent(GR_DESCHEDULE, t));
747 /* don't need to do anything. Either the thread is blocked on
748 * I/O, in which case we'll have called addToBlockedQueue
749 * previously, or it's blocked on an MVar or Blackhole, in which
750 * case it'll be on the relevant queue already.
753 fprintf(stderr, "thread %d stopped, ", t->id);
754 printThreadBlockage(t);
755 fprintf(stderr, "\n"));
760 /* Need to check whether this was a main thread, and if so, signal
761 * the task that started it with the return value. If we have no
762 * more main threads, we probably need to stop all the tasks until
765 IF_DEBUG(scheduler,belch("thread %ld finished", t->id));
766 t->whatNext = ThreadComplete;
768 // ToDo: endThread(t, CurrentProc); // clean-up the thread
770 advisory_thread_count--;
771 if (RtsFlags.ParFlags.ParStats.Full)
772 DumpEndEvent(CURRENT_PROC, t, rtsFalse /* not mandatory */);
777 barf("doneThread: invalid thread return code");
781 cap->link = free_capabilities;
782 free_capabilities = cap;
783 n_free_capabilities++;
787 if (ready_to_gc && n_free_capabilities == RtsFlags.ParFlags.nNodes)
792 /* everybody back, start the GC.
793 * Could do it in this thread, or signal a condition var
794 * to do it in another thread. Either way, we need to
795 * broadcast on gc_pending_cond afterward.
798 IF_DEBUG(scheduler,sched_belch("doing GC"));
800 GarbageCollect(GetRoots);
801 ready_to_gc = rtsFalse;
803 pthread_cond_broadcast(&gc_pending_cond);
808 IF_GRAN_DEBUG(unused,
809 print_eventq(EventHd));
811 event = get_next_event();
815 /* ToDo: wait for next message to arrive rather than busy wait */
820 t = take_off_run_queue(END_TSO_QUEUE);
823 } /* end of while(1) */
826 /* A hack for Hugs concurrency support. Needs sanitisation (?) */
827 void deleteAllThreads ( void )
830 IF_DEBUG(scheduler,sched_belch("deleteAllThreads()"));
831 for (t = run_queue_hd; t != END_TSO_QUEUE; t = t->link) {
834 for (t = blocked_queue_hd; t != END_TSO_QUEUE; t = t->link) {
837 run_queue_hd = run_queue_tl = END_TSO_QUEUE;
838 blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
841 /* startThread and insertThread are now in GranSim.c -- HWL */
843 //@node Suspend and Resume, Run queue code, Main scheduling loop, Main scheduling code
844 //@subsection Suspend and Resume
846 /* ---------------------------------------------------------------------------
847 * Suspending & resuming Haskell threads.
849 * When making a "safe" call to C (aka _ccall_GC), the task gives back
850 * its capability before calling the C function. This allows another
851 * task to pick up the capability and carry on running Haskell
852 * threads. It also means that if the C call blocks, it won't lock
855 * The Haskell thread making the C call is put to sleep for the
856 * duration of the call, on the susepended_ccalling_threads queue. We
857 * give out a token to the task, which it can use to resume the thread
858 * on return from the C function.
859 * ------------------------------------------------------------------------- */
862 suspendThread( Capability *cap )
866 ACQUIRE_LOCK(&sched_mutex);
869 sched_belch("thread %d did a _ccall_gc\n", cap->rCurrentTSO->id));
871 threadPaused(cap->rCurrentTSO);
872 cap->rCurrentTSO->link = suspended_ccalling_threads;
873 suspended_ccalling_threads = cap->rCurrentTSO;
875 /* Use the thread ID as the token; it should be unique */
876 tok = cap->rCurrentTSO->id;
879 cap->link = free_capabilities;
880 free_capabilities = cap;
881 n_free_capabilities++;
884 RELEASE_LOCK(&sched_mutex);
889 resumeThread( StgInt tok )
894 ACQUIRE_LOCK(&sched_mutex);
896 prev = &suspended_ccalling_threads;
897 for (tso = suspended_ccalling_threads;
898 tso != END_TSO_QUEUE;
899 prev = &tso->link, tso = tso->link) {
900 if (tso->id == (StgThreadID)tok) {
905 if (tso == END_TSO_QUEUE) {
906 barf("resumeThread: thread not found");
910 while (free_capabilities == NULL) {
911 IF_DEBUG(scheduler, sched_belch("waiting to resume"));
912 pthread_cond_wait(&thread_ready_cond, &sched_mutex);
913 IF_DEBUG(scheduler, sched_belch("resuming thread %d", tso->id));
915 cap = free_capabilities;
916 free_capabilities = cap->link;
917 n_free_capabilities--;
922 cap->rCurrentTSO = tso;
924 RELEASE_LOCK(&sched_mutex);
929 /* ---------------------------------------------------------------------------
931 * ------------------------------------------------------------------------ */
932 static void unblockThread(StgTSO *tso);
934 /* ---------------------------------------------------------------------------
935 * Comparing Thread ids.
937 * This is used from STG land in the implementation of the
938 * instances of Eq/Ord for ThreadIds.
939 * ------------------------------------------------------------------------ */
941 int cmp_thread(const StgTSO *tso1, const StgTSO *tso2)
943 StgThreadID id1 = tso1->id;
944 StgThreadID id2 = tso2->id;
946 if (id1 < id2) return (-1);
947 if (id1 > id2) return 1;
951 /* ---------------------------------------------------------------------------
954 The new thread starts with the given stack size. Before the
955 scheduler can run, however, this thread needs to have a closure
956 (and possibly some arguments) pushed on its stack. See
957 pushClosure() in Schedule.h.
959 createGenThread() and createIOThread() (in SchedAPI.h) are
960 convenient packaged versions of this function.
961 ------------------------------------------------------------------------ */
962 //@cindex createThread
964 /* currently pri (priority) is only used in a GRAN setup -- HWL */
966 createThread(nat stack_size, StgInt pri)
968 return createThread_(stack_size, rtsFalse, pri);
972 createThread_(nat size, rtsBool have_lock, StgInt pri)
976 createThread(nat stack_size)
978 return createThread_(stack_size, rtsFalse);
982 createThread_(nat size, rtsBool have_lock)
988 /* First check whether we should create a thread at all */
990 /* check that no more than RtsFlags.ParFlags.maxThreads threads are created */
991 if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads) {
993 belch("{createThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
994 RtsFlags.ParFlags.maxThreads, advisory_thread_count);
995 return END_TSO_QUEUE;
1001 ASSERT(!RtsFlags.GranFlags.Light || CurrentProc==0);
1004 // ToDo: check whether size = stack_size - TSO_STRUCT_SIZEW
1006 /* catch ridiculously small stack sizes */
1007 if (size < MIN_STACK_WORDS + TSO_STRUCT_SIZEW) {
1008 size = MIN_STACK_WORDS + TSO_STRUCT_SIZEW;
1011 tso = (StgTSO *)allocate(size);
1012 TICK_ALLOC_TSO(size-sizeofW(StgTSO),0);
1014 stack_size = size - TSO_STRUCT_SIZEW;
1016 // Hmm, this CCS_MAIN is not protected by a PROFILING cpp var;
1017 SET_HDR(tso, &TSO_info, CCS_MAIN);
1019 SET_GRAN_HDR(tso, ThisPE);
1021 tso->whatNext = ThreadEnterGHC;
1023 /* tso->id needs to be unique. For now we use a heavyweight mutex to
1024 protect the increment operation on next_thread_id.
1025 In future, we could use an atomic increment instead.
1028 if (!have_lock) { ACQUIRE_LOCK(&sched_mutex); }
1029 tso->id = next_thread_id++;
1030 if (!have_lock) { RELEASE_LOCK(&sched_mutex); }
1032 tso->why_blocked = NotBlocked;
1033 tso->blocked_exceptions = NULL;
1035 tso->splim = (P_)&(tso->stack) + RESERVED_STACK_WORDS;
1036 tso->stack_size = stack_size;
1037 tso->max_stack_size = round_to_mblocks(RtsFlags.GcFlags.maxStkSize)
1039 tso->sp = (P_)&(tso->stack) + stack_size;
1042 tso->prof.CCCS = CCS_MAIN;
1045 /* put a stop frame on the stack */
1046 tso->sp -= sizeofW(StgStopFrame);
1047 SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_MAIN);
1048 tso->su = (StgUpdateFrame*)tso->sp;
1050 IF_DEBUG(scheduler,belch("---- Initialised TSO %ld (%p), stack size = %lx words",
1051 tso->id, tso, tso->stack_size));
1055 tso->link = END_TSO_QUEUE;
1056 /* uses more flexible routine in GranSim */
1057 insertThread(tso, CurrentProc);
1059 /* In a non-GranSim setup the pushing of a TSO onto the runq is separated
1065 tso->gran.pri = pri;
1066 tso->gran.magic = TSO_MAGIC; // debugging only
1067 tso->gran.sparkname = 0;
1068 tso->gran.startedat = CURRENT_TIME;
1069 tso->gran.exported = 0;
1070 tso->gran.basicblocks = 0;
1071 tso->gran.allocs = 0;
1072 tso->gran.exectime = 0;
1073 tso->gran.fetchtime = 0;
1074 tso->gran.fetchcount = 0;
1075 tso->gran.blocktime = 0;
1076 tso->gran.blockcount = 0;
1077 tso->gran.blockedat = 0;
1078 tso->gran.globalsparks = 0;
1079 tso->gran.localsparks = 0;
1080 if (RtsFlags.GranFlags.Light)
1081 tso->gran.clock = Now; /* local clock */
1083 tso->gran.clock = 0;
1085 IF_DEBUG(gran,printTSO(tso));
1087 tso->par.sparkname = 0;
1088 tso->par.startedat = CURRENT_TIME;
1089 tso->par.exported = 0;
1090 tso->par.basicblocks = 0;
1091 tso->par.allocs = 0;
1092 tso->par.exectime = 0;
1093 tso->par.fetchtime = 0;
1094 tso->par.fetchcount = 0;
1095 tso->par.blocktime = 0;
1096 tso->par.blockcount = 0;
1097 tso->par.blockedat = 0;
1098 tso->par.globalsparks = 0;
1099 tso->par.localsparks = 0;
1103 globalGranStats.tot_threads_created++;
1104 globalGranStats.threads_created_on_PE[CurrentProc]++;
1105 globalGranStats.tot_sq_len += spark_queue_len(CurrentProc);
1106 globalGranStats.tot_sq_probes++;
1109 IF_DEBUG(scheduler,sched_belch("created thread %ld, stack size = %lx words",
1110 tso->id, tso->stack_size));
1114 /* ---------------------------------------------------------------------------
1117 * scheduleThread puts a thread on the head of the runnable queue.
1118 * This will usually be done immediately after a thread is created.
1119 * The caller of scheduleThread must create the thread using e.g.
1120 * createThread and push an appropriate closure
1121 * on this thread's stack before the scheduler is invoked.
1122 * ------------------------------------------------------------------------ */
1125 scheduleThread(StgTSO *tso)
1127 ACQUIRE_LOCK(&sched_mutex);
1129 /* Put the new thread on the head of the runnable queue. The caller
1130 * better push an appropriate closure on this thread's stack
1131 * beforehand. In the SMP case, the thread may start running as
1132 * soon as we release the scheduler lock below.
1134 PUSH_ON_RUN_QUEUE(tso);
1137 IF_DEBUG(scheduler,printTSO(tso));
1138 RELEASE_LOCK(&sched_mutex);
1141 /* ---------------------------------------------------------------------------
1144 * Start up Posix threads to run each of the scheduler tasks.
1145 * I believe the task ids are not needed in the system as defined.
1147 * ------------------------------------------------------------------------ */
1151 taskStart( void *arg STG_UNUSED )
1158 /* ---------------------------------------------------------------------------
1161 * Initialise the scheduler. This resets all the queues - if the
1162 * queues contained any threads, they'll be garbage collected at the
1165 * This now calls startTasks(), so should only be called once! KH @ 25/10/99
1166 * ------------------------------------------------------------------------ */
1170 term_handler(int sig STG_UNUSED)
1173 ACQUIRE_LOCK(&term_mutex);
1175 RELEASE_LOCK(&term_mutex);
1180 //@cindex initScheduler
1187 for (i=0; i<=MAX_PROC; i++) {
1188 run_queue_hds[i] = END_TSO_QUEUE;
1189 run_queue_tls[i] = END_TSO_QUEUE;
1190 blocked_queue_hds[i] = END_TSO_QUEUE;
1191 blocked_queue_tls[i] = END_TSO_QUEUE;
1192 ccalling_threadss[i] = END_TSO_QUEUE;
1195 run_queue_hd = END_TSO_QUEUE;
1196 run_queue_tl = END_TSO_QUEUE;
1197 blocked_queue_hd = END_TSO_QUEUE;
1198 blocked_queue_tl = END_TSO_QUEUE;
1201 suspended_ccalling_threads = END_TSO_QUEUE;
1203 main_threads = NULL;
1208 enteredCAFs = END_CAF_LIST;
1210 /* Install the SIGHUP handler */
1213 struct sigaction action,oact;
1215 action.sa_handler = term_handler;
1216 sigemptyset(&action.sa_mask);
1217 action.sa_flags = 0;
1218 if (sigaction(SIGTERM, &action, &oact) != 0) {
1219 barf("can't install TERM handler");
1225 /* Allocate N Capabilities */
1228 Capability *cap, *prev;
1231 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1232 cap = stgMallocBytes(sizeof(Capability), "initScheduler:capabilities");
1236 free_capabilities = cap;
1237 n_free_capabilities = RtsFlags.ParFlags.nNodes;
1239 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: Allocated %d capabilities\n",
1240 n_free_capabilities););
1243 #if defined(SMP) || defined(PAR)
1256 /* make some space for saving all the thread ids */
1257 task_ids = stgMallocBytes(RtsFlags.ParFlags.nNodes * sizeof(task_info),
1258 "initScheduler:task_ids");
1260 /* and create all the threads */
1261 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1262 r = pthread_create(&tid,NULL,taskStart,NULL);
1264 barf("startTasks: Can't create new Posix thread");
1266 task_ids[i].id = tid;
1267 task_ids[i].mut_time = 0.0;
1268 task_ids[i].mut_etime = 0.0;
1269 task_ids[i].gc_time = 0.0;
1270 task_ids[i].gc_etime = 0.0;
1271 task_ids[i].elapsedtimestart = elapsedtime();
1272 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: Started task: %ld\n",tid););
1278 exitScheduler( void )
1283 /* Don't want to use pthread_cancel, since we'd have to install
1284 * these silly exception handlers (pthread_cleanup_{push,pop}) around
1288 /* Cancel all our tasks */
1289 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1290 pthread_cancel(task_ids[i].id);
1293 /* Wait for all the tasks to terminate */
1294 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1295 IF_DEBUG(scheduler,fprintf(stderr,"scheduler: waiting for task %ld\n",
1297 pthread_join(task_ids[i].id, NULL);
1301 /* Send 'em all a SIGHUP. That should shut 'em up.
1303 await_death = RtsFlags.ParFlags.nNodes;
1304 for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
1305 pthread_kill(task_ids[i].id,SIGTERM);
1307 while (await_death > 0) {
1313 /* -----------------------------------------------------------------------------
1314 Managing the per-task allocation areas.
1316 Each capability comes with an allocation area. These are
1317 fixed-length block lists into which allocation can be done.
1319 ToDo: no support for two-space collection at the moment???
1320 -------------------------------------------------------------------------- */
1322 /* -----------------------------------------------------------------------------
1323 * waitThread is the external interface for running a new computataion
1324 * and waiting for the result.
1326 * In the non-SMP case, we create a new main thread, push it on the
1327 * main-thread stack, and invoke the scheduler to run it. The
1328 * scheduler will return when the top main thread on the stack has
1329 * completed or died, and fill in the necessary fields of the
1330 * main_thread structure.
1332 * In the SMP case, we create a main thread as before, but we then
1333 * create a new condition variable and sleep on it. When our new
1334 * main thread has completed, we'll be woken up and the status/result
1335 * will be in the main_thread struct.
1336 * -------------------------------------------------------------------------- */
1339 waitThread(StgTSO *tso, /*out*/StgClosure **ret)
1342 SchedulerStatus stat;
1344 ACQUIRE_LOCK(&sched_mutex);
1346 m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
1352 pthread_cond_init(&m->wakeup, NULL);
1355 m->link = main_threads;
1358 IF_DEBUG(scheduler, fprintf(stderr, "scheduler: new main thread (%d)\n",
1363 pthread_cond_wait(&m->wakeup, &sched_mutex);
1364 } while (m->stat == NoStatus);
1367 ASSERT(m->stat != NoStatus);
1373 pthread_cond_destroy(&m->wakeup);
1376 IF_DEBUG(scheduler, fprintf(stderr, "scheduler: main thread (%d) finished\n",
1380 RELEASE_LOCK(&sched_mutex);
1385 //@node Run queue code, Garbage Collextion Routines, Suspend and Resume, Main scheduling code
1386 //@subsection Run queue code
1390 NB: In GranSim we have many run queues; run_queue_hd is actually a macro
1391 unfolding to run_queue_hds[CurrentProc], thus CurrentProc is an
1392 implicit global variable that has to be correct when calling these
1396 /* Put the new thread on the head of the runnable queue.
1397 * The caller of createThread better push an appropriate closure
1398 * on this thread's stack before the scheduler is invoked.
1400 static /* inline */ void
1401 add_to_run_queue(tso)
1404 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
1405 tso->link = run_queue_hd;
1407 if (run_queue_tl == END_TSO_QUEUE) {
1412 /* Put the new thread at the end of the runnable queue. */
1413 static /* inline */ void
1414 push_on_run_queue(tso)
1417 ASSERT(get_itbl((StgClosure *)tso)->type == TSO);
1418 ASSERT(run_queue_hd!=NULL && run_queue_tl!=NULL);
1419 ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
1420 if (run_queue_hd == END_TSO_QUEUE) {
1423 run_queue_tl->link = tso;
1429 Should be inlined because it's used very often in schedule. The tso
1430 argument is actually only needed in GranSim, where we want to have the
1431 possibility to schedule *any* TSO on the run queue, irrespective of the
1432 actual ordering. Therefore, if tso is not the nil TSO then we traverse
1433 the run queue and dequeue the tso, adjusting the links in the queue.
1435 //@cindex take_off_run_queue
1436 static /* inline */ StgTSO*
1437 take_off_run_queue(StgTSO *tso) {
1441 qetlaHbogh Qu' ngaSbogh ghomDaQ {tso} yIteq!
1443 if tso is specified, unlink that tso from the run_queue (doesn't have
1444 to be at the beginning of the queue); GranSim only
1446 if (tso!=END_TSO_QUEUE) {
1447 /* find tso in queue */
1448 for (t=run_queue_hd, prev=END_TSO_QUEUE;
1449 t!=END_TSO_QUEUE && t!=tso;
1453 /* now actually dequeue the tso */
1454 if (prev!=END_TSO_QUEUE) {
1455 ASSERT(run_queue_hd!=t);
1456 prev->link = t->link;
1458 /* t is at beginning of thread queue */
1459 ASSERT(run_queue_hd==t);
1460 run_queue_hd = t->link;
1462 /* t is at end of thread queue */
1463 if (t->link==END_TSO_QUEUE) {
1464 ASSERT(t==run_queue_tl);
1465 run_queue_tl = prev;
1467 ASSERT(run_queue_tl!=t);
1469 t->link = END_TSO_QUEUE;
1471 /* take tso from the beginning of the queue; std concurrent code */
1473 if (t != END_TSO_QUEUE) {
1474 run_queue_hd = t->link;
1475 t->link = END_TSO_QUEUE;
1476 if (run_queue_hd == END_TSO_QUEUE) {
1477 run_queue_tl = END_TSO_QUEUE;
1486 //@node Garbage Collextion Routines, Blocking Queue Routines, Run queue code, Main scheduling code
1487 //@subsection Garbage Collextion Routines
1489 /* ---------------------------------------------------------------------------
1490 Where are the roots that we know about?
1492 - all the threads on the runnable queue
1493 - all the threads on the blocked queue
1494 - all the thread currently executing a _ccall_GC
1495 - all the "main threads"
1497 ------------------------------------------------------------------------ */
1499 /* This has to be protected either by the scheduler monitor, or by the
1500 garbage collection monitor (probably the latter).
1504 static void GetRoots(void)
1511 for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
1512 if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
1513 run_queue_hds[i] = (StgTSO *)MarkRoot((StgClosure *)run_queue_hds[i]);
1514 if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
1515 run_queue_tls[i] = (StgTSO *)MarkRoot((StgClosure *)run_queue_tls[i]);
1517 if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
1518 blocked_queue_hds[i] = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_hds[i]);
1519 if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
1520 blocked_queue_tls[i] = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_tls[i]);
1521 if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
1522 ccalling_threadss[i] = (StgTSO *)MarkRoot((StgClosure *)ccalling_threadss[i]);
1529 run_queue_hd = (StgTSO *)MarkRoot((StgClosure *)run_queue_hd);
1530 run_queue_tl = (StgTSO *)MarkRoot((StgClosure *)run_queue_tl);
1532 blocked_queue_hd = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_hd);
1533 blocked_queue_tl = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_tl);
1536 for (m = main_threads; m != NULL; m = m->link) {
1537 m->tso = (StgTSO *)MarkRoot((StgClosure *)m->tso);
1539 suspended_ccalling_threads =
1540 (StgTSO *)MarkRoot((StgClosure *)suspended_ccalling_threads);
1542 #if defined(SMP) || defined(PAR) || defined(GRAN)
1547 /* -----------------------------------------------------------------------------
1550 This is the interface to the garbage collector from Haskell land.
1551 We provide this so that external C code can allocate and garbage
1552 collect when called from Haskell via _ccall_GC.
1554 It might be useful to provide an interface whereby the programmer
1555 can specify more roots (ToDo).
1557 This needs to be protected by the GC condition variable above. KH.
1558 -------------------------------------------------------------------------- */
1560 void (*extra_roots)(void);
1565 GarbageCollect(GetRoots);
1571 GetRoots(); /* the scheduler's roots */
1572 extra_roots(); /* the user's roots */
1576 performGCWithRoots(void (*get_roots)(void))
1578 extra_roots = get_roots;
1580 GarbageCollect(AllRoots);
1583 /* -----------------------------------------------------------------------------
1586 If the thread has reached its maximum stack size,
1587 then bomb out. Otherwise relocate the TSO into a larger chunk of
1588 memory and adjust its stack size appropriately.
1589 -------------------------------------------------------------------------- */
1592 threadStackOverflow(StgTSO *tso)
1594 nat new_stack_size, new_tso_size, diff, stack_words;
1598 if (tso->stack_size >= tso->max_stack_size) {
1600 /* If we're debugging, just print out the top of the stack */
1601 printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
1605 fprintf(stderr, "fatal: stack overflow in Hugs; aborting\n" );
1608 /* Send this thread the StackOverflow exception */
1609 raiseAsync(tso, (StgClosure *)&stackOverflow_closure);
1614 /* Try to double the current stack size. If that takes us over the
1615 * maximum stack size for this thread, then use the maximum instead.
1616 * Finally round up so the TSO ends up as a whole number of blocks.
1618 new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
1619 new_tso_size = (nat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
1620 TSO_STRUCT_SIZE)/sizeof(W_);
1621 new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
1622 new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
1624 IF_DEBUG(scheduler, fprintf(stderr,"scheduler: increasing stack size from %d words to %d.\n", tso->stack_size, new_stack_size));
1626 dest = (StgTSO *)allocate(new_tso_size);
1627 TICK_ALLOC_TSO(new_tso_size-sizeofW(StgTSO),0);
1629 /* copy the TSO block and the old stack into the new area */
1630 memcpy(dest,tso,TSO_STRUCT_SIZE);
1631 stack_words = tso->stack + tso->stack_size - tso->sp;
1632 new_sp = (P_)dest + new_tso_size - stack_words;
1633 memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
1635 /* relocate the stack pointers... */
1636 diff = (P_)new_sp - (P_)tso->sp; /* In *words* */
1637 dest->su = (StgUpdateFrame *) ((P_)dest->su + diff);
1639 dest->splim = (P_)dest->splim + (nat)((P_)dest - (P_)tso);
1640 dest->stack_size = new_stack_size;
1642 /* and relocate the update frame list */
1643 relocate_TSO(tso, dest);
1645 /* Mark the old one as dead so we don't try to scavenge it during
1646 * garbage collection (the TSO will likely be on a mutables list in
1647 * some generation, but it'll get collected soon enough). It's
1648 * important to set the sp and su values to just beyond the end of
1649 * the stack, so we don't attempt to scavenge any part of the dead
1652 tso->whatNext = ThreadKilled;
1653 tso->sp = (P_)&(tso->stack[tso->stack_size]);
1654 tso->su = (StgUpdateFrame *)tso->sp;
1655 tso->why_blocked = NotBlocked;
1656 dest->mut_link = NULL;
1658 IF_DEBUG(sanity,checkTSO(tso));
1660 IF_DEBUG(scheduler,printTSO(dest));
1664 /* This will no longer work: KH */
1665 if (tso == MainTSO) { /* hack */
1672 //@node Blocking Queue Routines, Exception Handling Routines, Garbage Collextion Routines, Main scheduling code
1673 //@subsection Blocking Queue Routines
1675 /* ---------------------------------------------------------------------------
1676 Wake up a queue that was blocked on some resource.
1677 ------------------------------------------------------------------------ */
1679 /* ToDo: check push_on_run_queue vs. PUSH_ON_RUN_QUEUE */
1683 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
1688 unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
1690 /* write RESUME events to log file and
1691 update blocked and fetch time (depending on type of the orig closure) */
1692 if (RtsFlags.ParFlags.ParStats.Full) {
1693 DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
1694 GR_RESUMEQ, ((StgTSO *)bqe), ((StgTSO *)bqe)->block_info.closure,
1695 0, 0 /* spark_queue_len(ADVISORY_POOL) */);
1697 switch (get_itbl(node)->type) {
1699 ((StgTSO *)bqe)->par.fetchtime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
1704 ((StgTSO *)bqe)->par.blocktime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
1707 barf("{unblockOneLocked}Daq Qagh: unexpected closure in blocking queue");
1714 static StgBlockingQueueElement *
1715 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
1717 StgBlockingQueueElement *next;
1718 PEs node_loc, tso_loc;
1720 node_loc = where_is(node); // should be lifted out of loop
1721 tso = (StgTSO *)bqe; // wastes an assignment to get the type right
1722 tso_loc = where_is(tso);
1723 if (IS_LOCAL_TO(PROCS(node),tso_loc)) { // TSO is local
1724 /* !fake_fetch => TSO is on CurrentProc is same as IS_LOCAL_TO */
1725 ASSERT(CurrentProc!=node_loc || tso_loc==CurrentProc);
1726 bq_processing_time += RtsFlags.GranFlags.Costs.lunblocktime;
1727 // insertThread(tso, node_loc);
1728 new_event(tso_loc, tso_loc,
1729 CurrentTime[CurrentProc]+bq_processing_time,
1731 tso, node, (rtsSpark*)NULL);
1732 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
1735 } else { // TSO is remote (actually should be FMBQ)
1736 bq_processing_time += RtsFlags.GranFlags.Costs.mpacktime;
1737 bq_processing_time += RtsFlags.GranFlags.Costs.gunblocktime;
1738 new_event(tso_loc, CurrentProc,
1739 CurrentTime[CurrentProc]+bq_processing_time+
1740 RtsFlags.GranFlags.Costs.latency,
1742 tso, node, (rtsSpark*)NULL);
1743 tso->link = END_TSO_QUEUE; // overwrite link just to be sure
1744 bq_processing_time += RtsFlags.GranFlags.Costs.mtidytime;
1747 /* the thread-queue-overhead is accounted for in either Resume or UnblockThread */
1749 fprintf(stderr," %s TSO %d (%p) [PE %d] (blocked_on=%p) (next=%p) ,",
1750 (node_loc==tso_loc ? "Local" : "Global"),
1751 tso->id, tso, CurrentProc, tso->blocked_on, tso->link))
1752 tso->blocked_on = NULL;
1753 IF_DEBUG(scheduler,belch("-- Waking up thread %ld (%p)",
1757 /* if this is the BQ of an RBH, we have to put back the info ripped out of
1758 the closure to make room for the anchor of the BQ */
1759 if (next!=END_BQ_QUEUE) {
1760 ASSERT(get_itbl(node)->type == RBH && get_itbl(next)->type == CONSTR);
1762 ASSERT((info_ptr==&RBH_Save_0_info) ||
1763 (info_ptr==&RBH_Save_1_info) ||
1764 (info_ptr==&RBH_Save_2_info));
1766 /* cf. convertToRBH in RBH.c for writing the RBHSave closure */
1767 ((StgRBH *)node)->blocking_queue = ((StgRBHSave *)next)->payload[0];
1768 ((StgRBH *)node)->mut_link = ((StgRBHSave *)next)->payload[1];
1771 belch("## Filled in RBH_Save for %p (%s) at end of AwBQ",
1772 node, info_type(node)));
1776 static StgBlockingQueueElement *
1777 unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
1779 StgBlockingQueueElement *next;
1781 switch (get_itbl(bqe)->type) {
1783 ASSERT(((StgTSO *)bqe)->why_blocked != NotBlocked);
1784 /* if it's a TSO just push it onto the run_queue */
1786 // ((StgTSO *)bqe)->link = END_TSO_QUEUE; // debugging?
1787 PUSH_ON_RUN_QUEUE((StgTSO *)bqe);
1789 unblockCount(bqe, node);
1790 /* reset blocking status after dumping event */
1791 ((StgTSO *)bqe)->why_blocked = NotBlocked;
1795 /* if it's a BLOCKED_FETCH put it on the PendingFetches list */
1797 bqe->link = PendingFetches;
1798 PendingFetches = bqe;
1802 /* can ignore this case in a non-debugging setup;
1803 see comments on RBHSave closures above */
1805 /* check that the closure is an RBHSave closure */
1806 ASSERT(get_itbl((StgClosure *)bqe) == &RBH_Save_0_info ||
1807 get_itbl((StgClosure *)bqe) == &RBH_Save_1_info ||
1808 get_itbl((StgClosure *)bqe) == &RBH_Save_2_info);
1812 barf("{unblockOneLocked}Daq Qagh: Unexpected IP (%#lx; %s) in blocking queue at %#lx\n",
1813 get_itbl((StgClosure *)bqe), info_type((StgClosure *)bqe),
1817 // IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
1821 #else /* !GRAN && !PAR */
1823 unblockOneLocked(StgTSO *tso)
1827 ASSERT(get_itbl(tso)->type == TSO);
1828 ASSERT(tso->why_blocked != NotBlocked);
1829 tso->why_blocked = NotBlocked;
1831 PUSH_ON_RUN_QUEUE(tso);
1833 IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
1840 unblockOne(StgTSO *tso, StgClosure *node)
1842 ACQUIRE_LOCK(&sched_mutex);
1843 tso = unblockOneLocked(tso, node);
1844 RELEASE_LOCK(&sched_mutex);
1849 unblockOne(StgTSO *tso, StgClosure *node)
1851 ACQUIRE_LOCK(&sched_mutex);
1852 tso = unblockOneLocked(tso, node);
1853 RELEASE_LOCK(&sched_mutex);
1858 unblockOne(StgTSO *tso)
1860 ACQUIRE_LOCK(&sched_mutex);
1861 tso = unblockOneLocked(tso);
1862 RELEASE_LOCK(&sched_mutex);
1869 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
1871 StgBlockingQueueElement *bqe, *next;
1873 PEs node_loc, tso_loc;
1874 rtsTime bq_processing_time = 0;
1875 nat len = 0, len_local = 0;
1878 belch("## AwBQ for node %p on PE %d @ %ld by TSO %d (%p): ", \
1879 node, CurrentProc, CurrentTime[CurrentProc],
1880 CurrentTSO->id, CurrentTSO));
1882 node_loc = where_is(node);
1884 ASSERT(get_itbl(q)->type == TSO || // q is either a TSO or an RBHSave
1885 get_itbl(q)->type == CONSTR); // closure (type constructor)
1886 ASSERT(is_unique(node));
1888 /* FAKE FETCH: magically copy the node to the tso's proc;
1889 no Fetch necessary because in reality the node should not have been
1890 moved to the other PE in the first place
1892 if (CurrentProc!=node_loc) {
1894 belch("## node %p is on PE %d but CurrentProc is %d (TSO %d); assuming fake fetch and adjusting bitmask (old: %#x)",
1895 node, node_loc, CurrentProc, CurrentTSO->id,
1896 // CurrentTSO, where_is(CurrentTSO),
1897 node->header.gran.procs));
1898 node->header.gran.procs = (node->header.gran.procs) | PE_NUMBER(CurrentProc);
1900 belch("## new bitmask of node %p is %#x",
1901 node, node->header.gran.procs));
1902 if (RtsFlags.GranFlags.GranSimStats.Global) {
1903 globalGranStats.tot_fake_fetches++;
1908 // ToDo: check: ASSERT(CurrentProc==node_loc);
1909 while (get_itbl(bqe)->type==TSO) { // q != END_TSO_QUEUE) {
1912 bqe points to the current element in the queue
1913 next points to the next element in the queue
1915 //tso = (StgTSO *)bqe; // wastes an assignment to get the type right
1916 //tso_loc = where_is(tso);
1917 bqe = unblockOneLocked(bqe, node);
1920 /* statistics gathering */
1921 /* ToDo: fix counters
1922 if (RtsFlags.GranFlags.GranSimStats.Global) {
1923 globalGranStats.tot_bq_processing_time += bq_processing_time;
1924 globalGranStats.tot_bq_len += len; // total length of all bqs awakened
1925 globalGranStats.tot_bq_len_local += len_local; // same for local TSOs only
1926 globalGranStats.tot_awbq++; // total no. of bqs awakened
1929 fprintf(stderr,"## BQ Stats of %p: [%d entries, %d local] %s\n",
1930 node, len, len_local, (next!=END_TSO_QUEUE) ? "RBH" : ""));
1935 awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
1937 StgBlockingQueueElement *bqe, *next;
1939 ACQUIRE_LOCK(&sched_mutex);
1941 IF_PAR_DEBUG(verbose,
1942 belch("## AwBQ for node %p on [%x]: ",
1945 ASSERT(get_itbl(q)->type == TSO ||
1946 get_itbl(q)->type == BLOCKED_FETCH ||
1947 get_itbl(q)->type == CONSTR);
1950 while (get_itbl(bqe)->type==TSO ||
1951 get_itbl(bqe)->type==BLOCKED_FETCH) {
1952 bqe = unblockOneLocked(bqe, node);
1954 RELEASE_LOCK(&sched_mutex);
1957 #else /* !GRAN && !PAR */
1959 awakenBlockedQueue(StgTSO *tso)
1961 ACQUIRE_LOCK(&sched_mutex);
1962 while (tso != END_TSO_QUEUE) {
1963 tso = unblockOneLocked(tso);
1965 RELEASE_LOCK(&sched_mutex);
1969 //@node Exception Handling Routines, Debugging Routines, Blocking Queue Routines, Main scheduling code
1970 //@subsection Exception Handling Routines
1972 /* ---------------------------------------------------------------------------
1974 - usually called inside a signal handler so it mustn't do anything fancy.
1975 ------------------------------------------------------------------------ */
1978 interruptStgRts(void)
1984 /* -----------------------------------------------------------------------------
1987 This is for use when we raise an exception in another thread, which
1989 This has nothing to do with the UnblockThread event in GranSim. -- HWL
1990 -------------------------------------------------------------------------- */
1993 unblockThread(StgTSO *tso)
1997 ACQUIRE_LOCK(&sched_mutex);
1998 switch (tso->why_blocked) {
2001 return; /* not blocked */
2004 ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
2006 StgTSO *last_tso = END_TSO_QUEUE;
2007 StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
2010 for (t = mvar->head; t != END_TSO_QUEUE;
2011 last = &t->link, last_tso = t, t = t->link) {
2014 if (mvar->tail == tso) {
2015 mvar->tail = last_tso;
2020 barf("unblockThread (MVAR): TSO not found");
2023 case BlockedOnBlackHole:
2024 ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
2026 StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
2028 last = &bq->blocking_queue;
2029 for (t = bq->blocking_queue; t != END_TSO_QUEUE;
2030 last = &t->link, t = t->link) {
2036 barf("unblockThread (BLACKHOLE): TSO not found");
2039 case BlockedOnException:
2041 StgTSO *target = tso->block_info.tso;
2043 ASSERT(get_itbl(target)->type == TSO);
2044 ASSERT(target->blocked_exceptions != NULL);
2046 last = &target->blocked_exceptions;
2047 for (t = target->blocked_exceptions; t != END_TSO_QUEUE;
2048 last = &t->link, t = t->link) {
2049 ASSERT(get_itbl(t)->type == TSO);
2055 barf("unblockThread (Exception): TSO not found");
2058 case BlockedOnDelay:
2060 case BlockedOnWrite:
2062 StgTSO *prev = NULL;
2063 for (t = blocked_queue_hd; t != END_TSO_QUEUE;
2064 prev = t, t = t->link) {
2067 blocked_queue_hd = t->link;
2068 if (blocked_queue_tl == t) {
2069 blocked_queue_tl = END_TSO_QUEUE;
2072 prev->link = t->link;
2073 if (blocked_queue_tl == t) {
2074 blocked_queue_tl = prev;
2080 barf("unblockThread (I/O): TSO not found");
2084 barf("unblockThread");
2088 tso->link = END_TSO_QUEUE;
2089 tso->why_blocked = NotBlocked;
2090 tso->block_info.closure = NULL;
2091 PUSH_ON_RUN_QUEUE(tso);
2092 RELEASE_LOCK(&sched_mutex);
2095 /* -----------------------------------------------------------------------------
2098 * The following function implements the magic for raising an
2099 * asynchronous exception in an existing thread.
2101 * We first remove the thread from any queue on which it might be
2102 * blocked. The possible blockages are MVARs and BLACKHOLE_BQs.
2104 * We strip the stack down to the innermost CATCH_FRAME, building
2105 * thunks in the heap for all the active computations, so they can
2106 * be restarted if necessary. When we reach a CATCH_FRAME, we build
2107 * an application of the handler to the exception, and push it on
2108 * the top of the stack.
2110 * How exactly do we save all the active computations? We create an
2111 * AP_UPD for every UpdateFrame on the stack. Entering one of these
2112 * AP_UPDs pushes everything from the corresponding update frame
2113 * upwards onto the stack. (Actually, it pushes everything up to the
2114 * next update frame plus a pointer to the next AP_UPD object.
2115 * Entering the next AP_UPD object pushes more onto the stack until we
2116 * reach the last AP_UPD object - at which point the stack should look
2117 * exactly as it did when we killed the TSO and we can continue
2118 * execution by entering the closure on top of the stack.
2120 * We can also kill a thread entirely - this happens if either (a) the
2121 * exception passed to raiseAsync is NULL, or (b) there's no
2122 * CATCH_FRAME on the stack. In either case, we strip the entire
2123 * stack and replace the thread with a zombie.
2125 * -------------------------------------------------------------------------- */
2128 deleteThread(StgTSO *tso)
2130 raiseAsync(tso,NULL);
2134 raiseAsync(StgTSO *tso, StgClosure *exception)
2136 StgUpdateFrame* su = tso->su;
2137 StgPtr sp = tso->sp;
2139 /* Thread already dead? */
2140 if (tso->whatNext == ThreadComplete || tso->whatNext == ThreadKilled) {
2144 IF_DEBUG(scheduler, sched_belch("raising exception in thread %ld.", tso->id));
2146 /* Remove it from any blocking queues */
2149 /* The stack freezing code assumes there's a closure pointer on
2150 * the top of the stack. This isn't always the case with compiled
2151 * code, so we have to push a dummy closure on the top which just
2152 * returns to the next return address on the stack.
2154 if ( LOOKS_LIKE_GHC_INFO((void*)*sp) ) {
2155 *(--sp) = (W_)&dummy_ret_closure;
2159 int words = ((P_)su - (P_)sp) - 1;
2163 /* If we find a CATCH_FRAME, and we've got an exception to raise,
2164 * then build PAP(handler,exception), and leave it on top of
2165 * the stack ready to enter.
2167 if (get_itbl(su)->type == CATCH_FRAME && exception != NULL) {
2168 StgCatchFrame *cf = (StgCatchFrame *)su;
2169 /* we've got an exception to raise, so let's pass it to the
2170 * handler in this frame.
2172 ap = (StgAP_UPD *)allocate(sizeofW(StgPAP) + 1);
2173 TICK_ALLOC_UPD_PAP(2,0);
2174 SET_HDR(ap,&PAP_info,cf->header.prof.ccs);
2177 ap->fun = cf->handler;
2178 ap->payload[0] = (P_)exception;
2180 /* sp currently points to the word above the CATCH_FRAME on the stack.
2182 sp += sizeofW(StgCatchFrame);
2185 /* Restore the blocked/unblocked state for asynchronous exceptions
2186 * at the CATCH_FRAME.
2188 * If exceptions were unblocked at the catch, arrange that they
2189 * are unblocked again after executing the handler by pushing an
2190 * unblockAsyncExceptions_ret stack frame.
2192 if (!cf->exceptions_blocked) {
2193 *(sp--) = (W_)&unblockAsyncExceptionszh_ret_info;
2196 /* Ensure that async exceptions are blocked when running the handler.
2198 if (tso->blocked_exceptions == NULL) {
2199 tso->blocked_exceptions = END_TSO_QUEUE;
2202 /* Put the newly-built PAP on top of the stack, ready to execute
2203 * when the thread restarts.
2207 tso->whatNext = ThreadEnterGHC;
2211 /* First build an AP_UPD consisting of the stack chunk above the
2212 * current update frame, with the top word on the stack as the
2215 ap = (StgAP_UPD *)allocate(AP_sizeW(words));
2220 ap->fun = (StgClosure *)sp[0];
2222 for(i=0; i < (nat)words; ++i) {
2223 ap->payload[i] = (P_)*sp++;
2226 switch (get_itbl(su)->type) {
2230 SET_HDR(ap,&AP_UPD_info,su->header.prof.ccs /* ToDo */);
2231 TICK_ALLOC_UP_THK(words+1,0);
2234 fprintf(stderr, "scheduler: Updating ");
2235 printPtr((P_)su->updatee);
2236 fprintf(stderr, " with ");
2237 printObj((StgClosure *)ap);
2240 /* Replace the updatee with an indirection - happily
2241 * this will also wake up any threads currently
2242 * waiting on the result.
2244 UPD_IND_NOLOCK(su->updatee,ap); /* revert the black hole */
2246 sp += sizeofW(StgUpdateFrame) -1;
2247 sp[0] = (W_)ap; /* push onto stack */
2253 StgCatchFrame *cf = (StgCatchFrame *)su;
2256 /* We want a PAP, not an AP_UPD. Fortunately, the
2257 * layout's the same.
2259 SET_HDR(ap,&PAP_info,su->header.prof.ccs /* ToDo */);
2260 TICK_ALLOC_UPD_PAP(words+1,0);
2262 /* now build o = FUN(catch,ap,handler) */
2263 o = (StgClosure *)allocate(sizeofW(StgClosure)+2);
2264 TICK_ALLOC_FUN(2,0);
2265 SET_HDR(o,&catch_info,su->header.prof.ccs /* ToDo */);
2266 o->payload[0] = (StgClosure *)ap;
2267 o->payload[1] = cf->handler;
2270 fprintf(stderr, "scheduler: Built ");
2271 printObj((StgClosure *)o);
2274 /* pop the old handler and put o on the stack */
2276 sp += sizeofW(StgCatchFrame) - 1;
2283 StgSeqFrame *sf = (StgSeqFrame *)su;
2286 SET_HDR(ap,&PAP_info,su->header.prof.ccs /* ToDo */);
2287 TICK_ALLOC_UPD_PAP(words+1,0);
2289 /* now build o = FUN(seq,ap) */
2290 o = (StgClosure *)allocate(sizeofW(StgClosure)+1);
2291 TICK_ALLOC_SE_THK(1,0);
2292 SET_HDR(o,&seq_info,su->header.prof.ccs /* ToDo */);
2293 payloadCPtr(o,0) = (StgClosure *)ap;
2296 fprintf(stderr, "scheduler: Built ");
2297 printObj((StgClosure *)o);
2300 /* pop the old handler and put o on the stack */
2302 sp += sizeofW(StgSeqFrame) - 1;
2308 /* We've stripped the entire stack, the thread is now dead. */
2309 sp += sizeofW(StgStopFrame) - 1;
2310 sp[0] = (W_)exception; /* save the exception */
2311 tso->whatNext = ThreadKilled;
2312 tso->su = (StgUpdateFrame *)(sp+1);
2323 //@node Debugging Routines, Index, Exception Handling Routines, Main scheduling code
2324 //@subsection Debugging Routines
2326 /* -----------------------------------------------------------------------------
2327 Debugging: why is a thread blocked
2328 -------------------------------------------------------------------------- */
2332 void printThreadBlockage(StgTSO *tso)
2334 switch (tso->why_blocked) {
2336 fprintf(stderr,"blocked on read from fd %d", tso->block_info.fd);
2338 case BlockedOnWrite:
2339 fprintf(stderr,"blocked on write to fd %d", tso->block_info.fd);
2341 case BlockedOnDelay:
2342 fprintf(stderr,"blocked on delay of %d ms", tso->block_info.delay);
2345 fprintf(stderr,"blocked on an MVar");
2347 case BlockedOnException:
2348 fprintf(stderr,"blocked on delivering an exception to thread %d",
2349 tso->block_info.tso->id);
2351 case BlockedOnBlackHole:
2352 fprintf(stderr,"blocked on a black hole");
2355 fprintf(stderr,"not blocked");
2359 fprintf(stderr,"blocked on global address");
2366 Print a whole blocking queue attached to node (debugging only).
2371 print_bq (StgClosure *node)
2373 StgBlockingQueueElement *bqe;
2377 fprintf(stderr,"## BQ of closure %p (%s): ",
2378 node, info_type(node));
2380 /* should cover all closures that may have a blocking queue */
2381 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
2382 get_itbl(node)->type == FETCH_ME_BQ ||
2383 get_itbl(node)->type == RBH);
2385 ASSERT(node!=(StgClosure*)NULL); // sanity check
2387 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
2389 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
2390 !end; // iterate until bqe points to a CONSTR
2391 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
2392 ASSERT(bqe != END_BQ_QUEUE); // sanity check
2393 ASSERT(bqe != (StgTSO*)NULL); // sanity check
2394 /* types of closures that may appear in a blocking queue */
2395 ASSERT(get_itbl(bqe)->type == TSO ||
2396 get_itbl(bqe)->type == BLOCKED_FETCH ||
2397 get_itbl(bqe)->type == CONSTR);
2398 /* only BQs of an RBH end with an RBH_Save closure */
2399 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
2401 switch (get_itbl(bqe)->type) {
2403 fprintf(stderr," TSO %d (%x),",
2404 ((StgTSO *)bqe)->id, ((StgTSO *)bqe));
2407 fprintf(stderr," BF (node=%p, ga=((%x, %d, %x)),",
2408 ((StgBlockedFetch *)bqe)->node,
2409 ((StgBlockedFetch *)bqe)->ga.payload.gc.gtid,
2410 ((StgBlockedFetch *)bqe)->ga.payload.gc.slot,
2411 ((StgBlockedFetch *)bqe)->ga.weight);
2414 fprintf(stderr," %s (IP %p),",
2415 (get_itbl(bqe) == &RBH_Save_0_info ? "RBH_Save_0" :
2416 get_itbl(bqe) == &RBH_Save_1_info ? "RBH_Save_1" :
2417 get_itbl(bqe) == &RBH_Save_2_info ? "RBH_Save_2" :
2418 "RBH_Save_?"), get_itbl(bqe));
2421 barf("Unexpected closure type %s in blocking queue of %p (%s)",
2422 info_type(bqe), node, info_type(node));
2426 fputc('\n', stderr);
2428 # elif defined(GRAN)
2430 print_bq (StgClosure *node)
2432 StgBlockingQueueElement *bqe;
2434 PEs node_loc, tso_loc;
2437 /* should cover all closures that may have a blocking queue */
2438 ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
2439 get_itbl(node)->type == FETCH_ME_BQ ||
2440 get_itbl(node)->type == RBH);
2442 ASSERT(node!=(StgClosure*)NULL); // sanity check
2443 node_loc = where_is(node);
2445 fprintf(stderr,"## BQ of closure %p (%s) on [PE %d]: ",
2446 node, info_type(node), node_loc);
2449 NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
2451 for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
2452 !end; // iterate until bqe points to a CONSTR
2453 end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
2454 ASSERT(bqe != END_BQ_QUEUE); // sanity check
2455 ASSERT(bqe != (StgTSO*)NULL); // sanity check
2456 /* types of closures that may appear in a blocking queue */
2457 ASSERT(get_itbl(bqe)->type == TSO ||
2458 get_itbl(bqe)->type == CONSTR);
2459 /* only BQs of an RBH end with an RBH_Save closure */
2460 ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
2462 tso_loc = where_is((StgClosure *)bqe);
2463 switch (get_itbl(bqe)->type) {
2465 fprintf(stderr," TSO %d (%x) on [PE %d],",
2466 ((StgTSO *)bqe)->id, ((StgTSO *)bqe), tso_loc);
2469 fprintf(stderr," %s (IP %p),",
2470 (get_itbl(bqe) == &RBH_Save_0_info ? "RBH_Save_0" :
2471 get_itbl(bqe) == &RBH_Save_1_info ? "RBH_Save_1" :
2472 get_itbl(bqe) == &RBH_Save_2_info ? "RBH_Save_2" :
2473 "RBH_Save_?"), get_itbl(bqe));
2476 barf("Unexpected closure type %s in blocking queue of %p (%s)",
2477 info_type(bqe), node, info_type(node));
2481 fputc('\n', stderr);
2485 Nice and easy: only TSOs on the blocking queue
2488 print_bq (StgClosure *node)
2492 ASSERT(node!=(StgClosure*)NULL); // sanity check
2493 for (tso = ((StgBlockingQueue*)node)->blocking_queue;
2494 tso != END_TSO_QUEUE;
2496 ASSERT(tso!=NULL && tso!=END_TSO_QUEUE); // sanity check
2497 ASSERT(get_itbl(tso)->type == TSO); // guess what, sanity check
2498 fprintf(stderr," TSO %d (%p),", tso->id, tso);
2500 fputc('\n', stderr);
2511 for (i=0, tso=run_queue_hd;
2512 tso != END_TSO_QUEUE;
2521 sched_belch(char *s, ...)
2526 fprintf(stderr, "scheduler (task %ld): ", pthread_self());
2528 fprintf(stderr, "scheduler: ");
2530 vfprintf(stderr, s, ap);
2531 fprintf(stderr, "\n");
2536 //@node Index, , Debugging Routines, Main scheduling code
2540 //* MainRegTable:: @cindex\s-+MainRegTable
2541 //* StgMainThread:: @cindex\s-+StgMainThread
2542 //* awaken_blocked_queue:: @cindex\s-+awaken_blocked_queue
2543 //* blocked_queue_hd:: @cindex\s-+blocked_queue_hd
2544 //* blocked_queue_tl:: @cindex\s-+blocked_queue_tl
2545 //* context_switch:: @cindex\s-+context_switch
2546 //* createThread:: @cindex\s-+createThread
2547 //* free_capabilities:: @cindex\s-+free_capabilities
2548 //* gc_pending_cond:: @cindex\s-+gc_pending_cond
2549 //* initScheduler:: @cindex\s-+initScheduler
2550 //* interrupted:: @cindex\s-+interrupted
2551 //* n_free_capabilities:: @cindex\s-+n_free_capabilities
2552 //* next_thread_id:: @cindex\s-+next_thread_id
2553 //* print_bq:: @cindex\s-+print_bq
2554 //* run_queue_hd:: @cindex\s-+run_queue_hd
2555 //* run_queue_tl:: @cindex\s-+run_queue_tl
2556 //* sched_mutex:: @cindex\s-+sched_mutex
2557 //* schedule:: @cindex\s-+schedule
2558 //* take_off_run_queue:: @cindex\s-+take_off_run_queue
2559 //* task_ids:: @cindex\s-+task_ids
2560 //* term_mutex:: @cindex\s-+term_mutex
2561 //* thread_ready_cond:: @cindex\s-+thread_ready_cond