/* ---------------------------------------------------------------------------
- * $Id: Schedule.c,v 1.64 2000/04/05 15:28:59 simonmar Exp $
+ * $Id: Schedule.c,v 1.74 2000/08/03 11:28:35 simonmar Exp $
*
* (c) The GHC Team, 1998-2000
*
static StgTSO * createThread_ ( nat size, rtsBool have_lock );
#endif
+static void detectBlackHoles ( void );
+
#ifdef DEBUG
static void sched_belch(char *s, ...);
#endif
}
/* check for signals each time around the scheduler */
-#ifndef __MINGW32__
+#ifndef mingw32_TARGET_OS
if (signals_pending()) {
start_signal_handlers();
}
#endif
- /* Detect deadlock: when we have no threads to run, there are
- * no threads waiting on I/O or sleeping, and all the other
- * tasks are waiting for work, we must have a deadlock. Inform
- * all the main threads.
+ /*
+ * Detect deadlock: when we have no threads to run, there are no
+ * threads waiting on I/O or sleeping, and all the other tasks are
+ * waiting for work, we must have a deadlock of some description.
+ *
+ * We first try to find threads blocked on themselves (ie. black
+ * holes), and generate NonTermination exceptions where necessary.
+ *
+ * If no threads are black holed, we have a deadlock situation, so
+ * inform all the main threads.
*/
#ifdef SMP
if (blocked_queue_hd == END_TSO_QUEUE
&& run_queue_hd == END_TSO_QUEUE
- && (n_free_capabilities == RtsFlags.ParFlags.nNodes)
- ) {
- StgMainThread *m;
- for (m = main_threads; m != NULL; m = m->link) {
- m->ret = NULL;
- m->stat = Deadlock;
- pthread_cond_broadcast(&m->wakeup);
- }
- main_threads = NULL;
+ && (n_free_capabilities == RtsFlags.ParFlags.nNodes))
+ {
+ IF_DEBUG(scheduler, sched_belch("deadlocked, checking for black holes..."));
+ detectBlackHoles();
+ if (run_queue_hd == END_TSO_QUEUE) {
+ StgMainThread *m;
+ for (m = main_threads; m != NULL; m = m->link) {
+ m->ret = NULL;
+ m->stat = Deadlock;
+ pthread_cond_broadcast(&m->wakeup);
+ }
+ main_threads = NULL;
+ }
}
#else /* ! SMP */
- /*
- In GUM all non-main PEs come in here with no work;
- we ignore multiple main threads for now
-
if (blocked_queue_hd == END_TSO_QUEUE
- && run_queue_hd == END_TSO_QUEUE) {
- StgMainThread *m = main_threads;
- m->ret = NULL;
- m->stat = Deadlock;
- main_threads = m->link;
- return;
+ && run_queue_hd == END_TSO_QUEUE)
+ {
+ IF_DEBUG(scheduler, sched_belch("deadlocked, checking for black holes..."));
+ detectBlackHoles();
+ if (run_queue_hd == END_TSO_QUEUE) {
+ StgMainThread *m = main_threads;
+ m->ret = NULL;
+ m->stat = Deadlock;
+ main_threads = m->link;
+ return;
+ }
}
- */
#endif
#ifdef SMP
/* grab a thread from the run queue
*/
+ ASSERT(run_queue_hd != END_TSO_QUEUE);
t = POP_RUN_QUEUE();
IF_DEBUG(sanity,checkTSO(t));
cap->rCurrentTSO = t;
- /* set the context_switch flag
+ /* context switches are now initiated by the timer signal, unless
+ * the user specified "context switch as often as possible", with
+ * +RTS -C0
*/
- if (run_queue_hd == END_TSO_QUEUE)
- context_switch = 0;
+ if (RtsFlags.ConcFlags.ctxtSwitchTicks == 0
+ && (run_queue_hd != END_TSO_QUEUE
+ || blocked_queue_hd != END_TSO_QUEUE))
+ context_switch = 1;
else
- context_switch = 1;
+ context_switch = 0;
RELEASE_LOCK(&sched_mutex);
-#if defined(GRAN) || defined(PAR)
- IF_DEBUG(scheduler, belch("-->> Running TSO %ld (%p) %s ...",
+ IF_DEBUG(scheduler, sched_belch("-->> Running TSO %ld (%p) %s ...",
t->id, t, whatNext_strs[t->what_next]));
-#else
- IF_DEBUG(scheduler,sched_belch("running thread %d", t->id));
-#endif
/* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
/* Run the current thread
t->id, t, whatNext_strs[t->what_next]);
}
);
+
threadPaused(t);
+
IF_DEBUG(sanity,
//belch("&& Doing sanity check on yielding TSO %ld.", t->id);
checkTSO(t));
* case it'll be on the relevant queue already.
*/
IF_DEBUG(scheduler,
- fprintf(stderr, "--<< thread %d (%p) stopped ", t->id, t);
+ fprintf(stderr, "--<< thread %d (%p) stopped: ", t->id, t);
printThreadBlockage(t);
fprintf(stderr, "\n"));
* more main threads, we probably need to stop all the tasks until
* we get a new one.
*/
+ /* We also end up here if the thread kills itself with an
+ * uncaught exception, see Exception.hc.
+ */
IF_DEBUG(scheduler,belch("--++ thread %d (%p) finished", t->id, t));
- t->what_next = ThreadComplete;
#if defined(GRAN)
endThread(t, CurrentProc); // clean-up the thread
#elif defined(PAR)
break;
default:
- barf("doneThread: invalid thread return code");
+ barf("schedule: invalid thread return code %d", (int)ret);
}
#ifdef SMP
#ifdef SMP
IF_DEBUG(scheduler,sched_belch("doing GC"));
#endif
- GarbageCollect(GetRoots);
+ GarbageCollect(GetRoots,rtsFalse);
ready_to_gc = rtsFalse;
#ifdef SMP
pthread_cond_broadcast(&gc_pending_cond);
ACQUIRE_LOCK(&sched_mutex);
IF_DEBUG(scheduler,
- sched_belch("thread %d did a _ccall_gc\n", cap->rCurrentTSO->id));
+ sched_belch("thread %d did a _ccall_gc", cap->rCurrentTSO->id));
threadPaused(cap->rCurrentTSO);
cap->rCurrentTSO->link = suspended_ccalling_threads;
SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_SYSTEM);
tso->su = (StgUpdateFrame*)tso->sp;
- IF_DEBUG(scheduler,belch("---- Initialised TSO %ld (%p), stack size = %lx words",
- tso->id, tso, tso->stack_size));
-
// ToDo: check this
#if defined(GRAN)
tso->link = END_TSO_QUEUE;
PUSH_ON_RUN_QUEUE(tso);
THREAD_RUNNABLE();
+#if 0
IF_DEBUG(scheduler,printTSO(tso));
+#endif
RELEASE_LOCK(&sched_mutex);
}
context_switch = 0;
interrupted = 0;
- enteredCAFs = END_CAF_LIST;
+ RtsFlags.ConcFlags.ctxtSwitchTicks =
+ RtsFlags.ConcFlags.ctxtSwitchTime / TICK_MILLISECS;
+
+#ifdef INTERPRETER
+ ecafList = END_ECAF_LIST;
+ clearECafTable();
+#endif
/* Install the SIGHUP handler */
#ifdef SMP
* will be in the main_thread struct.
* -------------------------------------------------------------------------- */
+int
+howManyThreadsAvail ( void )
+{
+ int i = 0;
+ StgTSO* q;
+ for (q = run_queue_hd; q != END_TSO_QUEUE; q = q->link)
+ i++;
+ for (q = blocked_queue_hd; q != END_TSO_QUEUE; q = q->link)
+ i++;
+ return i;
+}
+
+void
+finishAllThreads ( void )
+{
+ do {
+ while (run_queue_hd != END_TSO_QUEUE) {
+ waitThread ( run_queue_hd, NULL );
+ }
+ while (blocked_queue_hd != END_TSO_QUEUE) {
+ waitThread ( blocked_queue_hd, NULL );
+ }
+ } while
+ (blocked_queue_hd != END_TSO_QUEUE ||
+ run_queue_hd != END_TSO_QUEUE);
+}
+
SchedulerStatus
waitThread(StgTSO *tso, /*out*/StgClosure **ret)
{
void
performGC(void)
{
- GarbageCollect(GetRoots);
+ GarbageCollect(GetRoots,rtsFalse);
+}
+
+void
+performMajorGC(void)
+{
+ GarbageCollect(GetRoots,rtsTrue);
}
static void
{
extra_roots = get_roots;
- GarbageCollect(AllRoots);
+ GarbageCollect(AllRoots,rtsFalse);
}
/* -----------------------------------------------------------------------------
sp[0] = (W_)ap;
tso->sp = sp;
tso->what_next = ThreadEnterGHC;
+ IF_DEBUG(sanity, checkTSO(tso));
return;
}
}
}
+/* -----------------------------------------------------------------------------
+ * Blackhole detection: if we reach a deadlock, test whether any
+ * threads are blocked on themselves. Any threads which are found to
+ * be self-blocked get sent a NonTermination exception.
+ *
+ * This is only done in a deadlock situation in order to avoid
+ * performance overhead in the normal case.
+ * -------------------------------------------------------------------------- */
+
+static void
+detectBlackHoles( void )
+{
+ StgTSO *t = all_threads;
+ StgUpdateFrame *frame;
+ StgClosure *blocked_on;
+
+ for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
+
+ if (t->why_blocked != BlockedOnBlackHole) {
+ continue;
+ }
+
+ blocked_on = t->block_info.closure;
+
+ for (frame = t->su; ; frame = frame->link) {
+ switch (get_itbl(frame)->type) {
+
+ case UPDATE_FRAME:
+ if (frame->updatee == blocked_on) {
+ /* We are blocking on one of our own computations, so
+ * send this thread the NonTermination exception.
+ */
+ IF_DEBUG(scheduler,
+ sched_belch("thread %d is blocked on itself", t->id));
+ raiseAsync(t, (StgClosure *)NonTermination_closure);
+ goto done;
+ }
+ else {
+ continue;
+ }
+
+ case CATCH_FRAME:
+ case SEQ_FRAME:
+ continue;
+
+ case STOP_FRAME:
+ break;
+ }
+ break;
+ }
+
+ done:
+ }
+}
+
//@node Debugging Routines, Index, Exception Handling Routines, Main scheduling code
//@subsection Debugging Routines
projects / ghc-hetmet.git / blobdiff