X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Frts%2FSchedule.c;h=17c7e74b598d855f6fb7dc5b0be0fce9c2974aab;hb=9c383315203f0ad7cfd65272d04d921c0cef3cec;hp=64c983ed5873f427b25c8e7e8d5ba701d31545d9;hpb=6a268d8669c50288f33d5bccd468522a8d56073a;p=ghc-hetmet.git diff --git a/ghc/rts/Schedule.c b/ghc/rts/Schedule.c index 64c983e..17c7e74 100644 --- a/ghc/rts/Schedule.c +++ b/ghc/rts/Schedule.c @@ -1,5 +1,5 @@ /* --------------------------------------------------------------------------- - * $Id: Schedule.c,v 1.141 2002/04/26 22:35:54 sof Exp $ + * $Id: Schedule.c,v 1.157 2002/10/22 11:01:19 simonmar Exp $ * * (c) The GHC Team, 1998-2000 * @@ -84,6 +84,7 @@ #include "StgRun.h" #include "StgStartup.h" #include "Hooks.h" +#define COMPILING_SCHEDULER #include "Schedule.h" #include "StgMiscClosures.h" #include "Storage.h" @@ -96,6 +97,7 @@ #include "Stats.h" #include "Itimer.h" #include "Prelude.h" +#include "ThreadLabels.h" #ifdef PROFILING #include "Proftimer.h" #include "ProfHeap.h" @@ -121,6 +123,8 @@ #include #endif +#include +#include #include //@node Variables and Data structures, Prototypes, Includes, Main scheduling code @@ -129,7 +133,7 @@ /* Main thread queue. * Locks required: sched_mutex. */ -StgMainThread *main_threads; +StgMainThread *main_threads = NULL; /* Thread queues. * Locks required: sched_mutex. @@ -156,16 +160,18 @@ StgTSO *ccalling_threadss[MAX_PROC]; #else /* !GRAN */ -StgTSO *run_queue_hd, *run_queue_tl; -StgTSO *blocked_queue_hd, *blocked_queue_tl; -StgTSO *sleeping_queue; /* perhaps replace with a hash table? */ +StgTSO *run_queue_hd = NULL; +StgTSO *run_queue_tl = NULL; +StgTSO *blocked_queue_hd = NULL; +StgTSO *blocked_queue_tl = NULL; +StgTSO *sleeping_queue = NULL; /* perhaps replace with a hash table? */ #endif /* Linked list of all threads. * Used for detecting garbage collected threads. */ -StgTSO *all_threads; +StgTSO *all_threads = NULL; /* When a thread performs a safe C call (_ccall_GC, using old * terminology), it gets put on the suspended_ccalling_threads @@ -182,17 +188,17 @@ static StgTSO *threadStackOverflow(StgTSO *tso); /* flag set by signal handler to precipitate a context switch */ //@cindex context_switch -nat context_switch; +nat context_switch = 0; /* if this flag is set as well, give up execution */ //@cindex interrupted -rtsBool interrupted; +rtsBool interrupted = rtsFalse; /* Next thread ID to allocate. - * Locks required: sched_mutex + * Locks required: thread_id_mutex */ //@cindex next_thread_id -StgThreadID next_thread_id = 1; +static StgThreadID next_thread_id = 1; /* * Pointers to the state of the current thread. @@ -223,17 +229,19 @@ StgTSO *CurrentTSO; */ StgTSO dummy_tso; -rtsBool ready_to_gc; +static rtsBool ready_to_gc; + +/* + * Set to TRUE when entering a shutdown state (via shutdownHaskellAndExit()) -- + * in an MT setting, needed to signal that a worker thread shouldn't hang around + * in the scheduler when it is out of work. + */ +static rtsBool shutting_down_scheduler = rtsFalse; void addToBlockedQueue ( StgTSO *tso ); static void schedule ( void ); void interruptStgRts ( void ); -#if defined(GRAN) -static StgTSO * createThread_ ( nat size, rtsBool have_lock, StgInt pri ); -#else -static StgTSO * createThread_ ( nat size, rtsBool have_lock ); -#endif static void detectBlackHoles ( void ); @@ -248,6 +256,13 @@ static void sched_belch(char *s, ...); Mutex sched_mutex = INIT_MUTEX_VAR; Mutex term_mutex = INIT_MUTEX_VAR; +/* + * A heavyweight solution to the problem of protecting + * the thread_id from concurrent update. + */ +Mutex thread_id_mutex = INIT_MUTEX_VAR; + + # if defined(SMP) static Condition gc_pending_cond = INIT_COND_VAR; nat await_death; @@ -262,21 +277,13 @@ rtsBool emitSchedule = rtsTrue; #endif #if DEBUG -char *whatNext_strs[] = { +static char *whatNext_strs[] = { "ThreadEnterGHC", "ThreadRunGHC", "ThreadEnterInterp", "ThreadKilled", "ThreadComplete" }; - -char *threadReturnCode_strs[] = { - "HeapOverflow", /* might also be StackOverflow */ - "StackOverflow", - "ThreadYielding", - "ThreadBlocked", - "ThreadFinished" -}; #endif #if defined(PAR) @@ -442,8 +449,7 @@ schedule( void ) m->stat = Success; broadcastCondition(&m->wakeup); #ifdef DEBUG - free(m->tso->label); - m->tso->label = NULL; + removeThreadLabel((StgWord)m->tso); #endif break; case ThreadKilled: @@ -456,8 +462,7 @@ schedule( void ) } broadcastCondition(&m->wakeup); #ifdef DEBUG - free(m->tso->label); - m->tso->label = NULL; + removeThreadLabel((StgWord)m->tso); #endif break; default: @@ -479,8 +484,7 @@ schedule( void ) if (m->tso->what_next == ThreadComplete || m->tso->what_next == ThreadKilled) { #ifdef DEBUG - free(m->tso->label); - m->tso->label = NULL; + removeThreadLabel((StgWord)m->tso); #endif main_threads = main_threads->link; if (m->tso->what_next == ThreadComplete) { @@ -714,15 +718,17 @@ schedule( void ) if ( EMPTY_RUN_QUEUE() ) { /* Give up our capability */ releaseCapability(cap); + + /* If we're in the process of shutting down (& running the + * a batch of finalisers), don't wait around. + */ + if ( shutting_down_scheduler ) { + RELEASE_LOCK(&sched_mutex); + return; + } IF_DEBUG(scheduler, sched_belch("thread %d: waiting for work", osThreadId())); waitForWorkCapability(&sched_mutex, &cap, rtsTrue); IF_DEBUG(scheduler, sched_belch("thread %d: work now available", osThreadId())); -#if 0 - while ( EMPTY_RUN_QUEUE() ) { - waitForWorkCapability(&sched_mutex, &cap); - IF_DEBUG(scheduler, sched_belch("thread %d: work now available", osThreadId())); - } -#endif } #endif @@ -1121,11 +1127,22 @@ schedule( void ) } cap->r.rCurrentNursery->u.back = bd; - // initialise it as a nursery block - bd->step = g0s0; - bd->gen_no = 0; - bd->flags = 0; - bd->free = bd->start; + // initialise it as a nursery block. We initialise the + // step, gen_no, and flags field of *every* sub-block in + // this large block, because this is easier than making + // sure that we always find the block head of a large + // block whenever we call Bdescr() (eg. evacuate() and + // isAlive() in the GC would both have to do this, at + // least). + { + bdescr *x; + for (x = bd; x < bd + blocks; x++) { + x->step = g0s0; + x->gen_no = 0; + x->flags = 0; + x->free = x->start; + } + } // don't forget to update the block count in g0s0. g0s0->n_blocks += blocks; @@ -1421,6 +1438,8 @@ StgInt forkProcess(StgTSO* tso) { #ifndef mingw32_TARGET_OS pid_t pid; StgTSO* t,*next; + StgMainThread *m; + rtsBool doKill; IF_DEBUG(scheduler,sched_belch("forking!")); @@ -1431,16 +1450,45 @@ StgInt forkProcess(StgTSO* tso) { } else { /* child */ /* wipe all other threads */ - run_queue_hd = tso; + run_queue_hd = run_queue_tl = tso; tso->link = END_TSO_QUEUE; + /* When clearing out the threads, we need to ensure + that a 'main thread' is left behind; if there isn't, + the Scheduler will shutdown next time it is entered. + + ==> we don't kill a thread that's on the main_threads + list (nor the current thread.) + + [ Attempts at implementing the more ambitious scheme of + killing the main_threads also, and then adding the + current thread onto the main_threads list if it wasn't + there already, failed -- waitThread() (for one) wasn't + up to it. If it proves to be desirable to also kill + the main threads, then this scheme will have to be + revisited (and fully debugged!) + + -- sof 7/2002 + ] + */ /* DO NOT TOUCH THE QUEUES directly because most of the code around - us is picky about finding the threat still in its queue when + us is picky about finding the thread still in its queue when handling the deleteThread() */ for (t = all_threads; t != END_TSO_QUEUE; t = next) { next = t->link; - if (t->id != tso->id) { + + /* Don't kill the current thread.. */ + if (t->id == tso->id) continue; + doKill=rtsTrue; + /* ..or a main thread */ + for (m = main_threads; m != NULL; m = m->link) { + if (m->tso->id == t->id) { + doKill=rtsFalse; + break; + } + } + if (doKill) { deleteThread(t); } } @@ -1609,10 +1657,11 @@ static void unblockThread(StgTSO *tso); * instances of Eq/Ord for ThreadIds. * ------------------------------------------------------------------------ */ -int cmp_thread(const StgTSO *tso1, const StgTSO *tso2) +int +cmp_thread(StgPtr tso1, StgPtr tso2) { - StgThreadID id1 = tso1->id; - StgThreadID id2 = tso2->id; + StgThreadID id1 = ((StgTSO *)tso1)->id; + StgThreadID id2 = ((StgTSO *)tso2)->id; if (id1 < id2) return (-1); if (id1 > id2) return 1; @@ -1624,27 +1673,28 @@ int cmp_thread(const StgTSO *tso1, const StgTSO *tso2) * * This is used in the implementation of Show for ThreadIds. * ------------------------------------------------------------------------ */ -int rts_getThreadId(const StgTSO *tso) +int +rts_getThreadId(StgPtr tso) { - return tso->id; + return ((StgTSO *)tso)->id; } #ifdef DEBUG -void labelThread(StgTSO *tso, char *label) +void +labelThread(StgPtr tso, char *label) { int len; void *buf; /* Caveat: Once set, you can only set the thread name to "" */ len = strlen(label)+1; - buf = realloc(tso->label,len); + buf = malloc(len); if (buf == NULL) { fprintf(stderr,"insufficient memory for labelThread!\n"); - free(tso->label); - tso->label = NULL; } else strncpy(buf,label,len); - tso->label = buf; + /* Update will free the old memory for us */ + updateThreadLabel((StgWord)tso,buf); } #endif /* DEBUG */ @@ -1665,25 +1715,12 @@ void labelThread(StgTSO *tso, char *label) #if defined(GRAN) /* currently pri (priority) is only used in a GRAN setup -- HWL */ StgTSO * -createThread(nat stack_size, StgInt pri) -{ - return createThread_(stack_size, rtsFalse, pri); -} - -static StgTSO * -createThread_(nat size, rtsBool have_lock, StgInt pri) -{ +createThread(nat size, StgInt pri) #else StgTSO * -createThread(nat stack_size) -{ - return createThread_(stack_size, rtsFalse); -} - -static StgTSO * -createThread_(nat size, rtsBool have_lock) -{ +createThread(nat size) #endif +{ StgTSO *tso; nat stack_size; @@ -1722,21 +1759,13 @@ createThread_(nat size, rtsBool have_lock) #endif tso->what_next = ThreadEnterGHC; -#ifdef DEBUG - tso->label = NULL; -#endif - /* tso->id needs to be unique. For now we use a heavyweight mutex to * protect the increment operation on next_thread_id. * In future, we could use an atomic increment instead. */ -#ifdef SMP - if (!have_lock) { ACQUIRE_LOCK(&sched_mutex); } -#endif + ACQUIRE_LOCK(&thread_id_mutex); tso->id = next_thread_id++; -#ifdef SMP - if (!have_lock) { RELEASE_LOCK(&sched_mutex); } -#endif + RELEASE_LOCK(&thread_id_mutex); tso->why_blocked = NotBlocked; tso->blocked_exceptions = NULL; @@ -1873,7 +1902,7 @@ createSparkThread(rtsSpark spark) } else { threadsCreated++; - tso = createThread_(RtsFlags.GcFlags.initialStkSize, rtsTrue); + tso = createThread(RtsFlags.GcFlags.initialStkSize); if (tso==END_TSO_QUEUE) barf("createSparkThread: Cannot create TSO"); #if defined(DIST) @@ -1914,6 +1943,13 @@ activateSpark (rtsSpark spark) } #endif +static SchedulerStatus waitThread_(/*out*/StgMainThread* m +#if defined(THREADED_RTS) + , rtsBool blockWaiting +#endif + ); + + /* --------------------------------------------------------------------------- * scheduleThread() * @@ -1960,12 +1996,48 @@ scheduleThread_(StgTSO *tso void scheduleThread(StgTSO* tso) { - return scheduleThread_(tso, rtsFalse); + scheduleThread_(tso, rtsFalse); } -void scheduleExtThread(StgTSO* tso) +SchedulerStatus +scheduleWaitThread(StgTSO* tso, /*[out]*/HaskellObj* ret) { - return scheduleThread_(tso, rtsTrue); + StgMainThread *m; + + m = stgMallocBytes(sizeof(StgMainThread), "waitThread"); + m->tso = tso; + m->ret = ret; + m->stat = NoStatus; +#if defined(RTS_SUPPORTS_THREADS) + initCondition(&m->wakeup); +#endif + + /* Put the thread on the main-threads list prior to scheduling the TSO. + Failure to do so introduces a race condition in the MT case (as + identified by Wolfgang Thaller), whereby the new task/OS thread + created by scheduleThread_() would complete prior to the thread + that spawned it managed to put 'itself' on the main-threads list. + The upshot of it all being that the worker thread wouldn't get to + signal the completion of the its work item for the main thread to + see (==> it got stuck waiting.) -- sof 6/02. + */ + ACQUIRE_LOCK(&sched_mutex); + IF_DEBUG(scheduler, sched_belch("== scheduler: waiting for thread (%d)\n", tso->id)); + + m->link = main_threads; + main_threads = m; + + /* Inefficient (scheduleThread_() acquires it again right away), + * but obviously correct. + */ + RELEASE_LOCK(&sched_mutex); + + scheduleThread_(tso, rtsTrue); +#if defined(THREADED_RTS) + return waitThread_(m, rtsTrue); +#else + return waitThread_(m); +#endif } /* --------------------------------------------------------------------------- @@ -2027,6 +2099,7 @@ initScheduler(void) * the scheduler. */ initMutex(&sched_mutex); initMutex(&term_mutex); + initMutex(&thread_id_mutex); initCondition(&thread_ready_cond); #endif @@ -2084,6 +2157,7 @@ exitScheduler( void ) #if defined(RTS_SUPPORTS_THREADS) stopTaskManager(); #endif + shutting_down_scheduler = rtsTrue; } /* ----------------------------------------------------------------------------- @@ -2147,40 +2221,41 @@ finishAllThreads ( void ) SchedulerStatus waitThread(StgTSO *tso, /*out*/StgClosure **ret) { + StgMainThread *m; + + m = stgMallocBytes(sizeof(StgMainThread), "waitThread"); + m->tso = tso; + m->ret = ret; + m->stat = NoStatus; +#if defined(RTS_SUPPORTS_THREADS) + initCondition(&m->wakeup); +#endif + + /* see scheduleWaitThread() comment */ + ACQUIRE_LOCK(&sched_mutex); + IF_DEBUG(scheduler, sched_belch("== scheduler: waiting for thread (%d)\n", tso->id)); + m->link = main_threads; + main_threads = m; + RELEASE_LOCK(&sched_mutex); + IF_DEBUG(scheduler, sched_belch("== scheduler: waiting for thread (%d)\n", tso->id)); #if defined(THREADED_RTS) - return waitThread_(tso,ret, rtsFalse); + return waitThread_(m, rtsFalse); #else - return waitThread_(tso,ret); + return waitThread_(m); #endif } +static SchedulerStatus -waitThread_(StgTSO *tso, - /*out*/StgClosure **ret +waitThread_(StgMainThread* m #if defined(THREADED_RTS) , rtsBool blockWaiting #endif ) { - StgMainThread *m; SchedulerStatus stat; - ACQUIRE_LOCK(&sched_mutex); - IF_DEBUG(scheduler, sched_belch("== scheduler: waiting for thread (%d)\n", tso->id)); - - m = stgMallocBytes(sizeof(StgMainThread), "waitThread"); - - m->tso = tso; - m->ret = ret; - m->stat = NoStatus; -#if defined(RTS_SUPPORTS_THREADS) - initCondition(&m->wakeup); -#endif - - m->link = main_threads; - main_threads = m; - IF_DEBUG(scheduler, sched_belch("== scheduler: new main thread (%d)\n", m->tso->id)); #if defined(RTS_SUPPORTS_THREADS) @@ -2191,12 +2266,12 @@ waitThread_(StgTSO *tso, * gets to enter the RTS directly without going via another * task/thread. */ - RELEASE_LOCK(&sched_mutex); schedule(); ASSERT(m->stat != NoStatus); } else # endif { + ACQUIRE_LOCK(&sched_mutex); do { waitCondition(&m->wakeup, &sched_mutex); } while (m->stat == NoStatus); @@ -2400,6 +2475,30 @@ GetRoots(evac_fn evac) #if defined(PAR) || defined(GRAN) markSparkQueue(evac); #endif + +#ifndef mingw32_TARGET_OS + // mark the signal handlers (signals should be already blocked) + markSignalHandlers(evac); +#endif + + // main threads which have completed need to be retained until they + // are dealt with in the main scheduler loop. They won't be + // retained any other way: the GC will drop them from the + // all_threads list, so we have to be careful to treat them as roots + // here. + { + StgMainThread *m; + for (m = main_threads; m != NULL; m = m->link) { + switch (m->tso->what_next) { + case ThreadComplete: + case ThreadKilled: + evac((StgClosure **)&m->tso); + break; + default: + break; + } + } + } } /* ----------------------------------------------------------------------------- @@ -2415,7 +2514,7 @@ GetRoots(evac_fn evac) This needs to be protected by the GC condition variable above. KH. -------------------------------------------------------------------------- */ -void (*extra_roots)(evac_fn); +static void (*extra_roots)(evac_fn); void performGC(void) @@ -3186,7 +3285,6 @@ raiseAsync(StgTSO *tso, StgClosure *exception) /* Remove it from any blocking queues */ unblockThread(tso); - IF_DEBUG(scheduler, sched_belch("raising exception in thread %ld.", tso->id)); /* The stack freezing code assumes there's a closure pointer on * the top of the stack. This isn't always the case with compiled * code, so we have to push a dummy closure on the top which just @@ -3201,6 +3299,8 @@ raiseAsync(StgTSO *tso, StgClosure *exception) nat i; StgAP_UPD * ap; + ASSERT((P_)su > (P_)sp); + /* If we find a CATCH_FRAME, and we've got an exception to raise, * then build the THUNK raise(exception), and leave it on * top of the CATCH_FRAME ready to enter. @@ -3248,8 +3348,6 @@ raiseAsync(StgTSO *tso, StgClosure *exception) */ ap = (StgAP_UPD *)allocate(AP_sizeW(words)); - ASSERT(words >= 0); - ap->n_args = words; ap->fun = (StgClosure *)sp[0]; sp++; @@ -3472,11 +3570,12 @@ detectBlackHoles( void ) //@subsection Debugging Routines /* ----------------------------------------------------------------------------- - Debugging: why is a thread blocked + * Debugging: why is a thread blocked + * [Also provides useful information when debugging threaded programs + * at the Haskell source code level, so enable outside of DEBUG. --sof 7/02] -------------------------------------------------------------------------- */ -#ifdef DEBUG - +static void printThreadBlockage(StgTSO *tso) { @@ -3524,6 +3623,7 @@ printThreadBlockage(StgTSO *tso) } } +static void printThreadStatus(StgTSO *tso) { @@ -3543,31 +3643,35 @@ void printAllThreads(void) { StgTSO *t; + void *label; # if defined(GRAN) char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN]; ullong_format_string(TIME_ON_PROC(CurrentProc), time_string, rtsFalse/*no commas!*/); - sched_belch("all threads at [%s]:", time_string); + fprintf(stderr, "all threads at [%s]:\n", time_string); # elif defined(PAR) char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN]; ullong_format_string(CURRENT_TIME, time_string, rtsFalse/*no commas!*/); - sched_belch("all threads at [%s]:", time_string); + fprintf(stderr,"all threads at [%s]:\n", time_string); # else - sched_belch("all threads:"); + fprintf(stderr,"all threads:\n"); # endif for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) { - fprintf(stderr, "\tthread %d ", t->id); - if (t->label) fprintf(stderr,"[\"%s\"] ",t->label); + fprintf(stderr, "\tthread %d @ %p ", t->id, (void *)t); + label = lookupThreadLabel((StgWord)t); + if (label) fprintf(stderr,"[\"%s\"] ",(char *)label); printThreadStatus(t); fprintf(stderr,"\n"); } } +#ifdef DEBUG + /* Print a whole blocking queue attached to node (debugging only). */ @@ -3750,6 +3854,7 @@ sched_belch(char *s, ...) #endif vfprintf(stderr, s, ap); fprintf(stderr, "\n"); + va_end(ap); } #endif /* DEBUG */