#include "PosixSource.h"
#define KEEP_LOCKCLOSURE
#include "Rts.h"
-#include "SchedAPI.h"
+
+#include "sm/Storage.h"
#include "RtsUtils.h"
-#include "RtsFlags.h"
-#include "OSThreads.h"
-#include "Storage.h"
#include "StgRun.h"
-#include "Hooks.h"
#include "Schedule.h"
-#include "StgMiscClosures.h"
#include "Interpreter.h"
#include "Printer.h"
#include "RtsSignals.h"
-#include "Sanity.h"
+#include "sm/Sanity.h"
#include "Stats.h"
#include "STM.h"
-#include "Timer.h"
#include "Prelude.h"
#include "ThreadLabels.h"
-#include "LdvProfile.h"
#include "Updates.h"
#include "Proftimer.h"
#include "ProfHeap.h"
-
-/* PARALLEL_HASKELL includes go here */
-
+#include "Weak.h"
+#include "sm/GC.h" // waitForGcThreads, releaseGCThreads, N
#include "Sparks.h"
#include "Capability.h"
#include "Task.h"
#include "Trace.h"
#include "RaiseAsync.h"
#include "Threads.h"
-#include "ThrIOManager.h"
+#include "Timer.h"
+#include "ThreadPaused.h"
+#include "Messages.h"
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#include <errno.h>
#endif
-// Turn off inlining when debugging - it obfuscates things
-#ifdef DEBUG
-# undef STATIC_INLINE
-# define STATIC_INLINE static
-#endif
-
/* -----------------------------------------------------------------------------
* Global variables
* -------------------------------------------------------------------------- */
StgTSO *sleeping_queue = NULL; // perhaps replace with a hash table?
#endif
-/* Threads blocked on blackholes.
- * LOCK: sched_mutex+capability, or all capabilities
- */
-StgTSO *blackhole_queue = NULL;
-
-/* The blackhole_queue should be checked for threads to wake up. See
- * Schedule.h for more thorough comment.
- * LOCK: none (doesn't matter if we miss an update)
+/* Set to true when the latest garbage collection failed to reclaim
+ * enough space, and the runtime should proceed to shut itself down in
+ * an orderly fashion (emitting profiling info etc.)
*/
-rtsBool blackholes_need_checking = rtsFalse;
+rtsBool heap_overflow = rtsFalse;
/* flag that tracks whether we have done any execution in this time slice.
* LOCK: currently none, perhaps we should lock (but needs to be
* updated in the fast path of the scheduler).
+ *
+ * NB. must be StgWord, we do xchg() on it.
*/
-nat recent_activity = ACTIVITY_YES;
+volatile StgWord recent_activity = ACTIVITY_YES;
/* if this flag is set as well, give up execution
- * LOCK: none (changes once, from false->true)
+ * LOCK: none (changes monotonically)
*/
-rtsBool sched_state = SCHED_RUNNING;
+volatile StgWord sched_state = SCHED_RUNNING;
/* This is used in `TSO.h' and gcc 2.96 insists that this variable actually
* exists - earlier gccs apparently didn't.
#endif
static void scheduleStartSignalHandlers (Capability *cap);
static void scheduleCheckBlockedThreads (Capability *cap);
-static void scheduleCheckWakeupThreads(Capability *cap USED_IF_NOT_THREADS);
-static void scheduleCheckBlackHoles (Capability *cap);
+static void scheduleProcessInbox(Capability *cap);
static void scheduleDetectDeadlock (Capability *cap, Task *task);
static void schedulePushWork(Capability *cap, Task *task);
-#if defined(PARALLEL_HASKELL)
-static rtsBool scheduleGetRemoteWork(Capability *cap);
-static void scheduleSendPendingMessages(void);
-#endif
-#if defined(PARALLEL_HASKELL) || defined(THREADED_RTS)
+#if defined(THREADED_RTS)
static void scheduleActivateSpark(Capability *cap);
#endif
static void schedulePostRunThread(Capability *cap, StgTSO *t);
static Capability *scheduleDoGC(Capability *cap, Task *task,
rtsBool force_major);
-static rtsBool checkBlackHoles(Capability *cap);
-
static StgTSO *threadStackOverflow(Capability *cap, StgTSO *tso);
-static StgTSO *threadStackUnderflow(Task *task, StgTSO *tso);
+static StgTSO *threadStackUnderflow(Capability *cap, Task *task, StgTSO *tso);
static void deleteThread (Capability *cap, StgTSO *tso);
static void deleteAllThreads (Capability *cap);
static void deleteThread_(Capability *cap, StgTSO *tso);
#endif
-#ifdef DEBUG
-static char *whatNext_strs[] = {
- "(unknown)",
- "ThreadRunGHC",
- "ThreadInterpret",
- "ThreadKilled",
- "ThreadRelocated",
- "ThreadComplete"
-};
-#endif
-
-/* -----------------------------------------------------------------------------
- * Putting a thread on the run queue: different scheduling policies
- * -------------------------------------------------------------------------- */
-
-STATIC_INLINE void
-addToRunQueue( Capability *cap, StgTSO *t )
-{
-#if defined(PARALLEL_HASKELL)
- if (RtsFlags.ParFlags.doFairScheduling) {
- // this does round-robin scheduling; good for concurrency
- appendToRunQueue(cap,t);
- } else {
- // this does unfair scheduling; good for parallelism
- pushOnRunQueue(cap,t);
- }
-#else
- // this does round-robin scheduling; good for concurrency
- appendToRunQueue(cap,t);
-#endif
-}
-
/* ---------------------------------------------------------------------------
Main scheduling loop.
StgTSO *t;
Capability *cap;
StgThreadReturnCode ret;
-#if defined(PARALLEL_HASKELL)
- rtsBool receivedFinish = rtsFalse;
-#endif
nat prev_what_next;
rtsBool ready_to_gc;
#if defined(THREADED_RTS)
// The sched_mutex is *NOT* held
// NB. on return, we still hold a capability.
- debugTrace (DEBUG_sched,
- "### NEW SCHEDULER LOOP (task: %p, cap: %p)",
- task, initialCapability);
+ debugTrace (DEBUG_sched, "cap %d: schedule()", initialCapability->no);
schedulePreLoop();
// -----------------------------------------------------------
// Scheduler loop starts here:
-#if defined(PARALLEL_HASKELL)
-#define TERMINATION_CONDITION (!receivedFinish)
-#else
-#define TERMINATION_CONDITION rtsTrue
-#endif
-
- while (TERMINATION_CONDITION) {
+ while (1) {
// Check whether we have re-entered the RTS from Haskell without
// going via suspendThread()/resumeThread (i.e. a 'safe' foreign
#endif
/* scheduleDoGC() deletes all the threads */
cap = scheduleDoGC(cap,task,rtsFalse);
- break;
+
+ // after scheduleDoGC(), we must be shutting down. Either some
+ // other Capability did the final GC, or we did it above,
+ // either way we can fall through to the SCHED_SHUTTING_DOWN
+ // case now.
+ ASSERT(sched_state == SCHED_SHUTTING_DOWN);
+ // fall through
+
case SCHED_SHUTTING_DOWN:
debugTrace(DEBUG_sched, "SCHED_SHUTTING_DOWN");
// If we are a worker, just exit. If we're a bound thread
// then we will exit below when we've removed our TSO from
// the run queue.
- if (task->tso == NULL && emptyRunQueue(cap)) {
+ if (!isBoundTask(task) && emptyRunQueue(cap)) {
return cap;
}
break;
(pushes threads, wakes up idle capabilities for stealing) */
schedulePushWork(cap,task);
-#if defined(PARALLEL_HASKELL)
- /* since we perform a blocking receive and continue otherwise,
- either we never reach here or we definitely have work! */
- // from here: non-empty run queue
- ASSERT(!emptyRunQueue(cap));
-
- if (PacketsWaiting()) { /* now process incoming messages, if any
- pending...
-
- CAUTION: scheduleGetRemoteWork called
- above, waits for messages as well! */
- processMessages(cap, &receivedFinish);
- }
-#endif // PARALLEL_HASKELL: non-empty run queue!
-
scheduleDetectDeadlock(cap,task);
#if defined(THREADED_RTS)
}
scheduleYield(&cap,task);
+
if (emptyRunQueue(cap)) continue; // look for work again
#endif
// Check whether we can run this thread in the current task.
// If not, we have to pass our capability to the right task.
{
- Task *bound = t->bound;
+ InCall *bound = t->bound;
if (bound) {
- if (bound == task) {
- debugTrace(DEBUG_sched,
- "### Running thread %lu in bound thread", (unsigned long)t->id);
+ if (bound->task == task) {
// yes, the Haskell thread is bound to the current native thread
} else {
debugTrace(DEBUG_sched,
- "### thread %lu bound to another OS thread", (unsigned long)t->id);
+ "thread %lu bound to another OS thread",
+ (unsigned long)t->id);
// no, bound to a different Haskell thread: pass to that thread
pushOnRunQueue(cap,t);
continue;
}
} else {
// The thread we want to run is unbound.
- if (task->tso) {
+ if (task->incall->tso) {
debugTrace(DEBUG_sched,
- "### this OS thread cannot run thread %lu", (unsigned long)t->id);
+ "this OS thread cannot run thread %lu",
+ (unsigned long)t->id);
// no, the current native thread is bound to a different
// Haskell thread, so pass it to any worker thread
pushOnRunQueue(cap,t);
}
#endif
+ // If we're shutting down, and this thread has not yet been
+ // killed, kill it now. This sometimes happens when a finalizer
+ // thread is created by the final GC, or a thread previously
+ // in a foreign call returns.
+ if (sched_state >= SCHED_INTERRUPTING &&
+ !(t->what_next == ThreadComplete || t->what_next == ThreadKilled)) {
+ deleteThread(cap,t);
+ }
+
/* context switches are initiated by the timer signal, unless
* the user specified "context switch as often as possible", with
* +RTS -C0
// that.
cap->r.rCurrentTSO = t;
- debugTrace(DEBUG_sched, "-->> running thread %ld %s ...",
- (long)t->id, whatNext_strs[t->what_next]);
-
startHeapProfTimer();
- // Check for exceptions blocked on this thread
- maybePerformBlockedException (cap, t);
-
// ----------------------------------------------------------------------
// Run the current thread
ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
ASSERT(t->cap == cap);
+ ASSERT(t->bound ? t->bound->task->cap == cap : 1);
prev_what_next = t->what_next;
if (prev == ACTIVITY_DONE_GC) {
startTimer();
}
- } else {
+ } else if (recent_activity != ACTIVITY_INACTIVE) {
+ // If we reached ACTIVITY_INACTIVE, then don't reset it until
+ // we've done the GC. The thread running here might just be
+ // the IO manager thread that handle_tick() woke up via
+ // wakeUpRts().
recent_activity = ACTIVITY_YES;
}
#endif
+ traceEventRunThread(cap, t);
+
switch (prev_what_next) {
case ThreadKilled:
// happened. So find the new location:
t = cap->r.rCurrentTSO;
- // We have run some Haskell code: there might be blackhole-blocked
- // threads to wake up now.
- // Lock-free test here should be ok, we're just setting a flag.
- if ( blackhole_queue != END_TSO_QUEUE ) {
- blackholes_need_checking = rtsTrue;
- }
-
// And save the current errno in this thread.
// XXX: possibly bogus for SMP because this thread might already
// be running again, see code below.
t->saved_winerror = GetLastError();
#endif
-#if defined(THREADED_RTS)
- // If ret is ThreadBlocked, and this Task is bound to the TSO that
- // blocked, we are in limbo - the TSO is now owned by whatever it
- // is blocked on, and may in fact already have been woken up,
- // perhaps even on a different Capability. It may be the case
- // that task->cap != cap. We better yield this Capability
- // immediately and return to normaility.
- if (ret == ThreadBlocked) {
- debugTrace(DEBUG_sched,
- "--<< thread %lu (%s) stopped: blocked",
- (unsigned long)t->id, whatNext_strs[t->what_next]);
- continue;
- }
-#endif
+ traceEventStopThread(cap, t, ret);
ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
ASSERT(t->cap == cap);
schedulePostRunThread(cap,t);
- t = threadStackUnderflow(task,t);
+ if (ret != StackOverflow) {
+ t = threadStackUnderflow(cap,task,t);
+ }
ready_to_gc = rtsFalse;
} /* end of while() */
}
+/* -----------------------------------------------------------------------------
+ * Run queue operations
+ * -------------------------------------------------------------------------- */
+
+void
+removeFromRunQueue (Capability *cap, StgTSO *tso)
+{
+ if (tso->block_info.prev == END_TSO_QUEUE) {
+ ASSERT(cap->run_queue_hd == tso);
+ cap->run_queue_hd = tso->_link;
+ } else {
+ setTSOLink(cap, tso->block_info.prev, tso->_link);
+ }
+ if (tso->_link == END_TSO_QUEUE) {
+ ASSERT(cap->run_queue_tl == tso);
+ cap->run_queue_tl = tso->block_info.prev;
+ } else {
+ setTSOPrev(cap, tso->_link, tso->block_info.prev);
+ }
+ tso->_link = tso->block_info.prev = END_TSO_QUEUE;
+
+ IF_DEBUG(sanity, checkRunQueue(cap));
+}
+
/* ----------------------------------------------------------------------------
* Setting up the scheduler loop
* ------------------------------------------------------------------------- */
{
scheduleStartSignalHandlers(cap);
- // Only check the black holes here if we've nothing else to do.
- // During normal execution, the black hole list only gets checked
- // at GC time, to avoid repeatedly traversing this possibly long
- // list each time around the scheduler.
- if (emptyRunQueue(cap)) { scheduleCheckBlackHoles(cap); }
-
- scheduleCheckWakeupThreads(cap);
+ scheduleProcessInbox(cap);
scheduleCheckBlockedThreads(cap);
-#if defined(THREADED_RTS) || defined(PARALLEL_HASKELL)
- // Try to activate one of our own sparks
- if (emptyRunQueue(cap)) { scheduleActivateSpark(cap); }
-#endif
-
#if defined(THREADED_RTS)
- // Try to steak work if we don't have any
- if (emptyRunQueue(cap)) { stealWork(cap); }
-#endif
-
-#if defined(PARALLEL_HASKELL)
- // if messages have been buffered...
- scheduleSendPendingMessages();
-#endif
-
-#if defined(PARALLEL_HASKELL)
- if (emptyRunQueue(cap)) {
- receivedFinish = scheduleGetRemoteWork(cap);
- continue; // a new round, (hopefully) with new work
- /*
- in GUM, this a) sends out a FISH and returns IF no fish is
- out already
- b) (blocking) awaits and receives messages
-
- in Eden, this is only the blocking receive, as b) in GUM.
- */
- }
+ if (emptyRunQueue(cap)) { scheduleActivateSpark(cap); }
#endif
}
// and this task it bound).
return (waiting_for_gc ||
cap->returning_tasks_hd != NULL ||
- (!emptyRunQueue(cap) && (task->tso == NULL
+ (!emptyRunQueue(cap) && (task->incall->tso == NULL
? cap->run_queue_hd->bound != NULL
- : cap->run_queue_hd->bound != task)));
+ : cap->run_queue_hd->bound != task->incall)));
}
// This is the single place where a Task goes to sleep. There are
// - we need to yield this Capability to someone else
// (see shouldYieldCapability())
//
-// The return value indicates whether
+// Careful: the scheduler loop is quite delicate. Make sure you run
+// the tests in testsuite/concurrent (all ways) after modifying this,
+// and also check the benchmarks in nofib/parallel for regressions.
static void
scheduleYield (Capability **pcap, Task *task)
Capability *cap = *pcap;
// if we have work, and we don't need to give up the Capability, continue.
- if (!emptyRunQueue(cap) && !shouldYieldCapability(cap,task))
+ //
+ if (!shouldYieldCapability(cap,task) &&
+ (!emptyRunQueue(cap) ||
+ !emptyInbox(cap) ||
+ sched_state >= SCHED_INTERRUPTING))
return;
// otherwise yield (sleep), and keep yielding if necessary.
Capability *free_caps[n_capabilities], *cap0;
nat i, n_free_caps;
- // migration can be turned off with +RTS -qg
+ // migration can be turned off with +RTS -qm
if (!RtsFlags.ParFlags.migrate) return;
// Check whether we have more threads on our run queue, or sparks
// in our pool, that we could hand to another Capability.
- if ((emptyRunQueue(cap) || cap->run_queue_hd->_link == END_TSO_QUEUE)
- && sparkPoolSizeCap(cap) < 2) {
- return;
+ if (cap->run_queue_hd == END_TSO_QUEUE) {
+ if (sparkPoolSizeCap(cap) < 2) return;
+ } else {
+ if (cap->run_queue_hd->_link == END_TSO_QUEUE &&
+ sparkPoolSizeCap(cap) < 1) return;
}
// First grab as many free Capabilities as we can.
for (i=0, n_free_caps=0; i < n_capabilities; i++) {
cap0 = &capabilities[i];
if (cap != cap0 && tryGrabCapability(cap0,task)) {
- if (!emptyRunQueue(cap0) || cap->returning_tasks_hd != NULL) {
+ if (!emptyRunQueue(cap0)
+ || cap->returning_tasks_hd != NULL
+ || cap->inbox != (Message*)END_TSO_QUEUE) {
// it already has some work, we just grabbed it at
// the wrong moment. Or maybe it's deadlocked!
releaseCapability(cap0);
next = t->_link;
t->_link = END_TSO_QUEUE;
if (t->what_next == ThreadRelocated
- || t->bound == task // don't move my bound thread
+ || t->bound == task->incall // don't move my bound thread
|| tsoLocked(t)) { // don't move a locked thread
setTSOLink(cap, prev, t);
+ setTSOPrev(cap, t, prev);
prev = t;
} else if (i == n_free_caps) {
pushed_to_all = rtsTrue;
i = 0;
// keep one for us
setTSOLink(cap, prev, t);
+ setTSOPrev(cap, t, prev);
prev = t;
} else {
- debugTrace(DEBUG_sched, "pushing thread %lu to capability %d", (unsigned long)t->id, free_caps[i]->no);
appendToRunQueue(free_caps[i],t);
- if (t->bound) { t->bound->cap = free_caps[i]; }
+
+ traceEventMigrateThread (cap, t, free_caps[i]->no);
+
+ if (t->bound) { t->bound->task->cap = free_caps[i]; }
t->cap = free_caps[i];
i++;
}
}
cap->run_queue_tl = prev;
+
+ IF_DEBUG(sanity, checkRunQueue(cap));
}
#ifdef SPARK_PUSHING
spark = tryStealSpark(cap->sparks);
if (spark != NULL) {
debugTrace(DEBUG_sched, "pushing spark %p to capability %d", spark, free_caps[i]->no);
+
+ traceEventStealSpark(free_caps[i], t, cap->no);
+
newSpark(&(free_caps[i]->r), spark);
}
}
//
if ( !emptyQueue(blocked_queue_hd) || !emptyQueue(sleeping_queue) )
{
- awaitEvent( emptyRunQueue(cap) && !blackholes_need_checking );
- }
-#endif
-}
-
-
-/* ----------------------------------------------------------------------------
- * Check for threads woken up by other Capabilities
- * ------------------------------------------------------------------------- */
-
-static void
-scheduleCheckWakeupThreads(Capability *cap USED_IF_THREADS)
-{
-#if defined(THREADED_RTS)
- // Any threads that were woken up by other Capabilities get
- // appended to our run queue.
- if (!emptyWakeupQueue(cap)) {
- ACQUIRE_LOCK(&cap->lock);
- if (emptyRunQueue(cap)) {
- cap->run_queue_hd = cap->wakeup_queue_hd;
- cap->run_queue_tl = cap->wakeup_queue_tl;
- } else {
- setTSOLink(cap, cap->run_queue_tl, cap->wakeup_queue_hd);
- cap->run_queue_tl = cap->wakeup_queue_tl;
- }
- cap->wakeup_queue_hd = cap->wakeup_queue_tl = END_TSO_QUEUE;
- RELEASE_LOCK(&cap->lock);
+ awaitEvent (emptyRunQueue(cap));
}
#endif
}
/* ----------------------------------------------------------------------------
- * Check for threads blocked on BLACKHOLEs that can be woken up
- * ------------------------------------------------------------------------- */
-static void
-scheduleCheckBlackHoles (Capability *cap)
-{
- if ( blackholes_need_checking ) // check without the lock first
- {
- ACQUIRE_LOCK(&sched_mutex);
- if ( blackholes_need_checking ) {
- checkBlackHoles(cap);
- blackholes_need_checking = rtsFalse;
- }
- RELEASE_LOCK(&sched_mutex);
- }
-}
-
-/* ----------------------------------------------------------------------------
* Detect deadlock conditions and attempt to resolve them.
* ------------------------------------------------------------------------- */
static void
scheduleDetectDeadlock (Capability *cap, Task *task)
{
-
-#if defined(PARALLEL_HASKELL)
- // ToDo: add deadlock detection in GUM (similar to THREADED_RTS) -- HWL
- return;
-#endif
-
/*
* Detect deadlock: when we have no threads to run, there are no
* threads blocked, waiting for I/O, or sleeping, and all the
// they are unreachable and will therefore be sent an
// exception. Any threads thus released will be immediately
// runnable.
- cap = scheduleDoGC (cap, task, rtsTrue/*force major GC*/);
+ cap = scheduleDoGC (cap, task, rtsTrue/*force major GC*/);
+ // when force_major == rtsTrue. scheduleDoGC sets
+ // recent_activity to ACTIVITY_DONE_GC and turns off the timer
+ // signal.
- recent_activity = ACTIVITY_DONE_GC;
- // disable timer signals (see #1623)
- stopTimer();
-
if ( !emptyRunQueue(cap) ) return;
#if defined(RTS_USER_SIGNALS) && !defined(THREADED_RTS)
/* Probably a real deadlock. Send the current main thread the
* Deadlock exception.
*/
- if (task->tso) {
- switch (task->tso->why_blocked) {
+ if (task->incall->tso) {
+ switch (task->incall->tso->why_blocked) {
case BlockedOnSTM:
case BlockedOnBlackHole:
- case BlockedOnException:
+ case BlockedOnMsgThrowTo:
case BlockedOnMVar:
- throwToSingleThreaded(cap, task->tso,
+ throwToSingleThreaded(cap, task->incall->tso,
(StgClosure *)nonTermination_closure);
return;
default:
#endif
/* ----------------------------------------------------------------------------
- * Activate spark threads (PARALLEL_HASKELL and THREADED_RTS)
+ * Process message in the current Capability's inbox
* ------------------------------------------------------------------------- */
-#if defined(PARALLEL_HASKELL) || defined(THREADED_RTS)
static void
-scheduleActivateSpark(Capability *cap)
+scheduleProcessInbox (Capability *cap USED_IF_THREADS)
{
- StgClosure *spark;
-
-/* We only want to stay here if the run queue is empty and we want some
- work. We try to turn a spark into a thread, and add it to the run
- queue, from where it will be picked up in the next iteration of the
- scheduler loop.
-*/
- if (!emptyRunQueue(cap))
- /* In the threaded RTS, another task might have pushed a thread
- on our run queue in the meantime ? But would need a lock.. */
- return;
-
-
- // Really we should be using reclaimSpark() here, but
- // experimentally it doesn't seem to perform as well as just
- // stealing from our own spark pool:
- // spark = reclaimSpark(cap->sparks);
- spark = tryStealSpark(cap->sparks); // defined in Sparks.c
-
- if (spark != NULL) {
- debugTrace(DEBUG_sched,
- "turning spark of closure %p into a thread",
- (StgClosure *)spark);
- createSparkThread(cap,spark); // defined in Sparks.c
+#if defined(THREADED_RTS)
+ Message *m;
+
+ while (!emptyInbox(cap)) {
+ ACQUIRE_LOCK(&cap->lock);
+ m = cap->inbox;
+ cap->inbox = m->link;
+ RELEASE_LOCK(&cap->lock);
+ executeMessage(cap, (Message *)m);
}
+#endif
}
-#endif // PARALLEL_HASKELL || THREADED_RTS
/* ----------------------------------------------------------------------------
- * Get work from a remote node (PARALLEL_HASKELL only)
+ * Activate spark threads (PARALLEL_HASKELL and THREADED_RTS)
* ------------------------------------------------------------------------- */
-
-#if defined(PARALLEL_HASKELL)
-static rtsBool /* return value used in PARALLEL_HASKELL only */
-scheduleGetRemoteWork (Capability *cap STG_UNUSED)
-{
-#if defined(PARALLEL_HASKELL)
- rtsBool receivedFinish = rtsFalse;
-
- // idle() , i.e. send all buffers, wait for work
- if (RtsFlags.ParFlags.BufferTime) {
- IF_PAR_DEBUG(verbose,
- debugBelch("...send all pending data,"));
- {
- nat i;
- for (i=1; i<=nPEs; i++)
- sendImmediately(i); // send all messages away immediately
- }
- }
-
- /* this would be the place for fishing in GUM...
-
- if (no-earlier-fish-around)
- sendFish(choosePe());
- */
-
- // Eden:just look for incoming messages (blocking receive)
- IF_PAR_DEBUG(verbose,
- debugBelch("...wait for incoming messages...\n"));
- processMessages(cap, &receivedFinish); // blocking receive...
-
-
- return receivedFinish;
- // reenter scheduling look after having received something
-
-#else /* !PARALLEL_HASKELL, i.e. THREADED_RTS */
- return rtsFalse; /* return value unused in THREADED_RTS */
-
-#endif /* PARALLEL_HASKELL */
+#if defined(THREADED_RTS)
+static void
+scheduleActivateSpark(Capability *cap)
+{
+ if (anySparks())
+ {
+ createSparkThread(cap);
+ debugTrace(DEBUG_sched, "creating a spark thread");
+ }
}
#endif // PARALLEL_HASKELL || THREADED_RTS
// ATOMICALLY_FRAME, aborting the (nested)
// transaction, and saving the stack of any
// partially-evaluated thunks on the heap.
- throwToSingleThreaded_(cap, t, NULL, rtsTrue, NULL);
+ throwToSingleThreaded_(cap, t, NULL, rtsTrue);
- ASSERT(get_itbl((StgClosure *)t->sp)->type == ATOMICALLY_FRAME);
+// ASSERT(get_itbl((StgClosure *)t->sp)->type == ATOMICALLY_FRAME);
}
}
debugTrace(DEBUG_sched,
"--<< thread %ld (%s) stopped: requesting a large block (size %ld)\n",
- (long)t->id, whatNext_strs[t->what_next], blocks);
+ (long)t->id, what_next_strs[t->what_next], blocks);
// don't do this if the nursery is (nearly) full, we'll GC first.
if (cap->r.rCurrentNursery->link != NULL ||
if (cap->r.rCurrentNursery->u.back != NULL) {
cap->r.rCurrentNursery->u.back->link = bd;
} else {
-#if !defined(THREADED_RTS)
- ASSERT(g0s0->blocks == cap->r.rCurrentNursery &&
- g0s0 == cap->r.rNursery);
-#endif
cap->r.rNursery->blocks = bd;
}
cap->r.rCurrentNursery->u.back = bd;
{
bdescr *x;
for (x = bd; x < bd + blocks; x++) {
- x->step = cap->r.rNursery;
- x->gen_no = 0;
+ initBdescr(x,g0,g0);
+ x->free = x->start;
x->flags = 0;
}
}
}
}
- debugTrace(DEBUG_sched,
- "--<< thread %ld (%s) stopped: HeapOverflow",
- (long)t->id, whatNext_strs[t->what_next]);
-
- if (cap->context_switch) {
+ if (cap->r.rHpLim == NULL || cap->context_switch) {
// Sometimes we miss a context switch, e.g. when calling
// primitives in a tight loop, MAYBE_GC() doesn't check the
// context switch flag, and we end up waiting for a GC.
// See #1984, and concurrent/should_run/1984
cap->context_switch = 0;
- addToRunQueue(cap,t);
+ appendToRunQueue(cap,t);
} else {
pushOnRunQueue(cap,t);
}
static void
scheduleHandleStackOverflow (Capability *cap, Task *task, StgTSO *t)
{
- debugTrace (DEBUG_sched,
- "--<< thread %ld (%s) stopped, StackOverflow",
- (long)t->id, whatNext_strs[t->what_next]);
-
/* just adjust the stack for this thread, then pop it back
* on the run queue.
*/
/* The TSO attached to this Task may have moved, so update the
* pointer to it.
*/
- if (task->tso == t) {
- task->tso = new_t;
+ if (task->incall->tso == t) {
+ task->incall->tso = new_t;
}
pushOnRunQueue(cap,new_t);
}
static rtsBool
scheduleHandleYield( Capability *cap, StgTSO *t, nat prev_what_next )
{
- // Reset the context switch flag. We don't do this just before
- // running the thread, because that would mean we would lose ticks
- // during GC, which can lead to unfair scheduling (a thread hogs
- // the CPU because the tick always arrives during GC). This way
- // penalises threads that do a lot of allocation, but that seems
- // better than the alternative.
- cap->context_switch = 0;
-
/* put the thread back on the run queue. Then, if we're ready to
* GC, check whether this is the last task to stop. If so, wake
* up the GC thread. getThread will block during a GC until the
* GC is finished.
*/
-#ifdef DEBUG
- if (t->what_next != prev_what_next) {
- debugTrace(DEBUG_sched,
- "--<< thread %ld (%s) stopped to switch evaluators",
- (long)t->id, whatNext_strs[t->what_next]);
- } else {
- debugTrace(DEBUG_sched,
- "--<< thread %ld (%s) stopped, yielding",
- (long)t->id, whatNext_strs[t->what_next]);
- }
-#endif
-
- IF_DEBUG(sanity,
- //debugBelch("&& Doing sanity check on yielding TSO %ld.", t->id);
- checkTSO(t));
+
ASSERT(t->_link == END_TSO_QUEUE);
// Shortcut if we're just switching evaluators: don't bother
// doing stack squeezing (which can be expensive), just run the
// thread.
- if (t->what_next != prev_what_next) {
+ if (cap->context_switch == 0 && t->what_next != prev_what_next) {
+ debugTrace(DEBUG_sched,
+ "--<< thread %ld (%s) stopped to switch evaluators",
+ (long)t->id, what_next_strs[t->what_next]);
return rtsTrue;
}
- addToRunQueue(cap,t);
+ // Reset the context switch flag. We don't do this just before
+ // running the thread, because that would mean we would lose ticks
+ // during GC, which can lead to unfair scheduling (a thread hogs
+ // the CPU because the tick always arrives during GC). This way
+ // penalises threads that do a lot of allocation, but that seems
+ // better than the alternative.
+ cap->context_switch = 0;
+
+ IF_DEBUG(sanity,
+ //debugBelch("&& Doing sanity check on yielding TSO %ld.", t->id);
+ checkTSO(t));
+
+ appendToRunQueue(cap,t);
return rtsFalse;
}
static void
scheduleHandleThreadBlocked( StgTSO *t
-#if !defined(GRAN) && !defined(DEBUG)
+#if !defined(DEBUG)
STG_UNUSED
#endif
)
// ASSERT(t->why_blocked != NotBlocked);
// Not true: for example,
- // - in THREADED_RTS, the thread may already have been woken
- // up by another Capability. This actually happens: try
- // conc023 +RTS -N2.
// - the thread may have woken itself up already, because
// threadPaused() might have raised a blocked throwTo
// exception, see maybePerformBlockedException().
#ifdef DEBUG
- if (traceClass(DEBUG_sched)) {
- debugTraceBegin("--<< thread %lu (%s) stopped: ",
- (unsigned long)t->id, whatNext_strs[t->what_next]);
- printThreadBlockage(t);
- debugTraceEnd();
- }
+ traceThreadStatus(DEBUG_sched, t);
#endif
}
* We also end up here if the thread kills itself with an
* uncaught exception, see Exception.cmm.
*/
- debugTrace(DEBUG_sched, "--++ thread %lu (%s) finished",
- (unsigned long)t->id, whatNext_strs[t->what_next]);
+
+ // blocked exceptions can now complete, even if the thread was in
+ // blocked mode (see #2910).
+ awakenBlockedExceptionQueue (cap, t);
//
// Check whether the thread that just completed was a bound
if (t->bound) {
- if (t->bound != task) {
+ if (t->bound != task->incall) {
#if !defined(THREADED_RTS)
// Must be a bound thread that is not the topmost one. Leave
// it on the run queue until the stack has unwound to the
#endif
}
- ASSERT(task->tso == t);
+ ASSERT(task->incall->tso == t);
if (t->what_next == ThreadComplete) {
- if (task->ret) {
+ if (task->incall->ret) {
// NOTE: return val is tso->sp[1] (see StgStartup.hc)
- *(task->ret) = (StgClosure *)task->tso->sp[1];
+ *(task->incall->ret) = (StgClosure *)task->incall->tso->sp[1];
}
- task->stat = Success;
+ task->incall->stat = Success;
} else {
- if (task->ret) {
- *(task->ret) = NULL;
+ if (task->incall->ret) {
+ *(task->incall->ret) = NULL;
}
if (sched_state >= SCHED_INTERRUPTING) {
- task->stat = Interrupted;
+ if (heap_overflow) {
+ task->incall->stat = HeapExhausted;
+ } else {
+ task->incall->stat = Interrupted;
+ }
} else {
- task->stat = Killed;
+ task->incall->stat = Killed;
}
}
#ifdef DEBUG
- removeThreadLabel((StgWord)task->tso->id);
+ removeThreadLabel((StgWord)task->incall->tso->id);
#endif
+
+ // We no longer consider this thread and task to be bound to
+ // each other. The TSO lives on until it is GC'd, but the
+ // task is about to be released by the caller, and we don't
+ // want anyone following the pointer from the TSO to the
+ // defunct task (which might have already been
+ // re-used). This was a real bug: the GC updated
+ // tso->bound->tso which lead to a deadlock.
+ t->bound = NULL;
+ task->incall->tso = NULL;
+
return rtsTrue; // tells schedule() to return
}
#ifdef THREADED_RTS
/* extern static volatile StgWord waiting_for_gc;
lives inside capability.c */
- rtsBool was_waiting;
+ rtsBool gc_type, prev_pending_gc;
nat i;
#endif
+ if (sched_state == SCHED_SHUTTING_DOWN) {
+ // The final GC has already been done, and the system is
+ // shutting down. We'll probably deadlock if we try to GC
+ // now.
+ return cap;
+ }
+
#ifdef THREADED_RTS
+ if (sched_state < SCHED_INTERRUPTING
+ && RtsFlags.ParFlags.parGcEnabled
+ && N >= RtsFlags.ParFlags.parGcGen
+ && ! oldest_gen->mark)
+ {
+ gc_type = PENDING_GC_PAR;
+ } else {
+ gc_type = PENDING_GC_SEQ;
+ }
+
// In order to GC, there must be no threads running Haskell code.
// Therefore, the GC thread needs to hold *all* the capabilities,
// and release them after the GC has completed.
// actually did the GC. But it's quite hard to arrange for all
// the other tasks to sleep and stay asleep.
//
-
+
/* Other capabilities are prevented from running yet more Haskell
threads if waiting_for_gc is set. Tested inside
yieldCapability() and releaseCapability() in Capability.c */
- was_waiting = cas(&waiting_for_gc, 0, 1);
- if (was_waiting) {
+ prev_pending_gc = cas(&waiting_for_gc, 0, gc_type);
+ if (prev_pending_gc) {
do {
- debugTrace(DEBUG_sched, "someone else is trying to GC...");
- if (cap) yieldCapability(&cap,task);
+ debugTrace(DEBUG_sched, "someone else is trying to GC (%d)...",
+ prev_pending_gc);
+ ASSERT(cap);
+ yieldCapability(&cap,task);
} while (waiting_for_gc);
return cap; // NOTE: task->cap might have changed here
}
setContextSwitches();
- for (i=0; i < n_capabilities; i++) {
- debugTrace(DEBUG_sched, "ready_to_gc, grabbing all the capabilies (%d/%d)", i, n_capabilities);
- if (cap != &capabilities[i]) {
- Capability *pcap = &capabilities[i];
- // we better hope this task doesn't get migrated to
- // another Capability while we're waiting for this one.
- // It won't, because load balancing happens while we have
- // all the Capabilities, but even so it's a slightly
- // unsavoury invariant.
- task->cap = pcap;
- waitForReturnCapability(&pcap, task);
- if (pcap != &capabilities[i]) {
- barf("scheduleDoGC: got the wrong capability");
- }
- }
+
+ // The final shutdown GC is always single-threaded, because it's
+ // possible that some of the Capabilities have no worker threads.
+
+ if (gc_type == PENDING_GC_SEQ)
+ {
+ traceEventRequestSeqGc(cap);
+ }
+ else
+ {
+ traceEventRequestParGc(cap);
+ debugTrace(DEBUG_sched, "ready_to_gc, grabbing GC threads");
+ }
+
+ if (gc_type == PENDING_GC_SEQ)
+ {
+ // single-threaded GC: grab all the capabilities
+ for (i=0; i < n_capabilities; i++) {
+ debugTrace(DEBUG_sched, "ready_to_gc, grabbing all the capabilies (%d/%d)", i, n_capabilities);
+ if (cap != &capabilities[i]) {
+ Capability *pcap = &capabilities[i];
+ // we better hope this task doesn't get migrated to
+ // another Capability while we're waiting for this one.
+ // It won't, because load balancing happens while we have
+ // all the Capabilities, but even so it's a slightly
+ // unsavoury invariant.
+ task->cap = pcap;
+ waitForReturnCapability(&pcap, task);
+ if (pcap != &capabilities[i]) {
+ barf("scheduleDoGC: got the wrong capability");
+ }
+ }
+ }
+ }
+ else
+ {
+ // multi-threaded GC: make sure all the Capabilities donate one
+ // GC thread each.
+ waitForGcThreads(cap);
}
- waiting_for_gc = rtsFalse;
#endif
- // so this happens periodically:
- if (cap) scheduleCheckBlackHoles(cap);
-
IF_DEBUG(scheduler, printAllThreads());
+delete_threads_and_gc:
/*
* We now have all the capabilities; if we're in an interrupting
* state, then we should take the opportunity to delete all the
* threads in the system.
*/
- if (sched_state >= SCHED_INTERRUPTING) {
- deleteAllThreads(&capabilities[0]);
+ if (sched_state == SCHED_INTERRUPTING) {
+ deleteAllThreads(cap);
sched_state = SCHED_SHUTTING_DOWN;
}
heap_census = scheduleNeedHeapProfile(rtsTrue);
- /* everybody back, start the GC.
- * Could do it in this thread, or signal a condition var
- * to do it in another thread. Either way, we need to
- * broadcast on gc_pending_cond afterward.
- */
+ traceEventGcStart(cap);
#if defined(THREADED_RTS)
- debugTrace(DEBUG_sched, "doing GC");
+ // reset waiting_for_gc *before* GC, so that when the GC threads
+ // emerge they don't immediately re-enter the GC.
+ waiting_for_gc = 0;
+ GarbageCollect(force_major || heap_census, gc_type, cap);
+#else
+ GarbageCollect(force_major || heap_census, 0, cap);
#endif
- GarbageCollect(force_major || heap_census);
-
+ traceEventGcEnd(cap);
+
+ if (recent_activity == ACTIVITY_INACTIVE && force_major)
+ {
+ // We are doing a GC because the system has been idle for a
+ // timeslice and we need to check for deadlock. Record the
+ // fact that we've done a GC and turn off the timer signal;
+ // it will get re-enabled if we run any threads after the GC.
+ recent_activity = ACTIVITY_DONE_GC;
+ stopTimer();
+ }
+ else
+ {
+ // the GC might have taken long enough for the timer to set
+ // recent_activity = ACTIVITY_INACTIVE, but we aren't
+ // necessarily deadlocked:
+ recent_activity = ACTIVITY_YES;
+ }
+
+#if defined(THREADED_RTS)
+ if (gc_type == PENDING_GC_PAR)
+ {
+ releaseGCThreads(cap);
+ }
+#endif
+
if (heap_census) {
debugTrace(DEBUG_sched, "performing heap census");
heapCensus();
performHeapProfile = rtsFalse;
}
+ if (heap_overflow && sched_state < SCHED_INTERRUPTING) {
+ // GC set the heap_overflow flag, so we should proceed with
+ // an orderly shutdown now. Ultimately we want the main
+ // thread to return to its caller with HeapExhausted, at which
+ // point the caller should call hs_exit(). The first step is
+ // to delete all the threads.
+ //
+ // Another way to do this would be to raise an exception in
+ // the main thread, which we really should do because it gives
+ // the program a chance to clean up. But how do we find the
+ // main thread? It should presumably be the same one that
+ // gets ^C exceptions, but that's all done on the Haskell side
+ // (GHC.TopHandler).
+ sched_state = SCHED_INTERRUPTING;
+ goto delete_threads_and_gc;
+ }
+
#ifdef SPARKBALANCE
/* JB
Once we are all together... this would be the place to balance all
#endif
#if defined(THREADED_RTS)
- // release our stash of capabilities.
- for (i = 0; i < n_capabilities; i++) {
- if (cap != &capabilities[i]) {
- task->cap = &capabilities[i];
- releaseCapability(&capabilities[i]);
- }
+ if (gc_type == PENDING_GC_SEQ) {
+ // release our stash of capabilities.
+ for (i = 0; i < n_capabilities; i++) {
+ if (cap != &capabilities[i]) {
+ task->cap = &capabilities[i];
+ releaseCapability(&capabilities[i]);
+ }
+ }
}
if (cap) {
task->cap = cap;
)
{
#ifdef FORKPROCESS_PRIMOP_SUPPORTED
- Task *task;
pid_t pid;
StgTSO* t,*next;
Capability *cap;
- nat s;
+ nat g;
#if defined(THREADED_RTS)
if (RtsFlags.ParFlags.nNodes > 1) {
ACQUIRE_LOCK(&cap->lock);
ACQUIRE_LOCK(&cap->running_task->lock);
+ stopTimer(); // See #4074
+
pid = fork();
if (pid) { // parent
+ startTimer(); // #4074
+
RELEASE_LOCK(&sched_mutex);
RELEASE_LOCK(&cap->lock);
RELEASE_LOCK(&cap->running_task->lock);
// all Tasks, because they correspond to OS threads that are
// now gone.
- for (s = 0; s < total_steps; s++) {
- for (t = all_steps[s].threads; t != END_TSO_QUEUE; t = next) {
+ for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
+ for (t = generations[g].threads; t != END_TSO_QUEUE; t = next) {
if (t->what_next == ThreadRelocated) {
next = t->_link;
} else {
// exception, but we do want to raiseAsync() because these
// threads may be evaluating thunks that we need later.
deleteThread_(cap,t);
+
+ // stop the GC from updating the InCall to point to
+ // the TSO. This is only necessary because the
+ // OSThread bound to the TSO has been killed, and
+ // won't get a chance to exit in the usual way (see
+ // also scheduleHandleThreadFinished).
+ t->bound = NULL;
}
}
}
// Any suspended C-calling Tasks are no more, their OS threads
// don't exist now:
- cap->suspended_ccalling_tasks = NULL;
+ cap->suspended_ccalls = NULL;
// Empty the threads lists. Otherwise, the garbage
// collector may attempt to resurrect some of these threads.
- for (s = 0; s < total_steps; s++) {
- all_steps[s].threads = END_TSO_QUEUE;
+ for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
+ generations[g].threads = END_TSO_QUEUE;
}
- // Wipe the task list, except the current Task.
- ACQUIRE_LOCK(&sched_mutex);
- for (task = all_tasks; task != NULL; task=task->all_link) {
- if (task != cap->running_task) {
-#if defined(THREADED_RTS)
- initMutex(&task->lock); // see #1391
-#endif
- discardTask(task);
- }
- }
- RELEASE_LOCK(&sched_mutex);
+ discardTasksExcept(cap->running_task);
#if defined(THREADED_RTS)
// Wipe our spare workers list, they no longer exist. New
initTimer();
startTimer();
+#if defined(THREADED_RTS)
+ cap = ioManagerStartCap(cap);
+#endif
+
cap = rts_evalStableIO(cap, entry, NULL); // run the action
rts_checkSchedStatus("forkProcess",cap);
}
#else /* !FORKPROCESS_PRIMOP_SUPPORTED */
barf("forkProcess#: primop not supported on this platform, sorry!\n");
- return -1;
#endif
}
// NOTE: only safe to call if we own all capabilities.
StgTSO* t, *next;
- nat s;
+ nat g;
debugTrace(DEBUG_sched,"deleting all threads");
- for (s = 0; s < total_steps; s++) {
- for (t = all_steps[s].threads; t != END_TSO_QUEUE; t = next) {
- if (t->what_next == ThreadRelocated) {
- next = t->_link;
- } else {
- next = t->global_link;
- deleteThread(cap,t);
- }
- }
- }
+ for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
+ for (t = generations[g].threads; t != END_TSO_QUEUE; t = next) {
+ if (t->what_next == ThreadRelocated) {
+ next = t->_link;
+ } else {
+ next = t->global_link;
+ deleteThread(cap,t);
+ }
+ }
+ }
// The run queue now contains a bunch of ThreadKilled threads. We
// must not throw these away: the main thread(s) will be in there
}
/* -----------------------------------------------------------------------------
- Managing the suspended_ccalling_tasks list.
+ Managing the suspended_ccalls list.
Locks required: sched_mutex
-------------------------------------------------------------------------- */
STATIC_INLINE void
suspendTask (Capability *cap, Task *task)
{
- ASSERT(task->next == NULL && task->prev == NULL);
- task->next = cap->suspended_ccalling_tasks;
- task->prev = NULL;
- if (cap->suspended_ccalling_tasks) {
- cap->suspended_ccalling_tasks->prev = task;
+ InCall *incall;
+
+ incall = task->incall;
+ ASSERT(incall->next == NULL && incall->prev == NULL);
+ incall->next = cap->suspended_ccalls;
+ incall->prev = NULL;
+ if (cap->suspended_ccalls) {
+ cap->suspended_ccalls->prev = incall;
}
- cap->suspended_ccalling_tasks = task;
+ cap->suspended_ccalls = incall;
}
STATIC_INLINE void
recoverSuspendedTask (Capability *cap, Task *task)
{
- if (task->prev) {
- task->prev->next = task->next;
+ InCall *incall;
+
+ incall = task->incall;
+ if (incall->prev) {
+ incall->prev->next = incall->next;
} else {
- ASSERT(cap->suspended_ccalling_tasks == task);
- cap->suspended_ccalling_tasks = task->next;
+ ASSERT(cap->suspended_ccalls == incall);
+ cap->suspended_ccalls = incall->next;
}
- if (task->next) {
- task->next->prev = task->prev;
+ if (incall->next) {
+ incall->next->prev = incall->prev;
}
- task->next = task->prev = NULL;
+ incall->next = incall->prev = NULL;
}
/* ---------------------------------------------------------------------------
* the whole system.
*
* The Haskell thread making the C call is put to sleep for the
- * duration of the call, on the susepended_ccalling_threads queue. We
+ * duration of the call, on the suspended_ccalling_threads queue. We
* give out a token to the task, which it can use to resume the thread
* on return from the C function.
+ *
+ * If this is an interruptible C call, this means that the FFI call may be
+ * unceremoniously terminated and should be scheduled on an
+ * unbound worker thread.
* ------------------------------------------------------------------------- */
void *
-suspendThread (StgRegTable *reg)
+suspendThread (StgRegTable *reg, rtsBool interruptible)
{
Capability *cap;
int saved_errno;
task = cap->running_task;
tso = cap->r.rCurrentTSO;
- debugTrace(DEBUG_sched,
- "thread %lu did a safe foreign call",
- (unsigned long)cap->r.rCurrentTSO->id);
+ traceEventStopThread(cap, tso, THREAD_SUSPENDED_FOREIGN_CALL);
// XXX this might not be necessary --SDM
tso->what_next = ThreadRunGHC;
threadPaused(cap,tso);
- if ((tso->flags & TSO_BLOCKEX) == 0) {
- tso->why_blocked = BlockedOnCCall;
- tso->flags |= TSO_BLOCKEX;
- tso->flags &= ~TSO_INTERRUPTIBLE;
+ if (interruptible) {
+ tso->why_blocked = BlockedOnCCall_Interruptible;
} else {
- tso->why_blocked = BlockedOnCCall_NoUnblockExc;
+ tso->why_blocked = BlockedOnCCall;
}
// Hand back capability
- task->suspended_tso = tso;
+ task->incall->suspended_tso = tso;
+ task->incall->suspended_cap = cap;
ACQUIRE_LOCK(&cap->lock);
RELEASE_LOCK(&cap->lock);
-#if defined(THREADED_RTS)
- /* Preparing to leave the RTS, so ensure there's a native thread/task
- waiting to take over.
- */
- debugTrace(DEBUG_sched, "thread %lu: leaving RTS", (unsigned long)tso->id);
-#endif
-
errno = saved_errno;
#if mingw32_HOST_OS
SetLastError(saved_winerror);
resumeThread (void *task_)
{
StgTSO *tso;
+ InCall *incall;
Capability *cap;
Task *task = task_;
int saved_errno;
saved_winerror = GetLastError();
#endif
- cap = task->cap;
+ incall = task->incall;
+ cap = incall->suspended_cap;
+ task->cap = cap;
+
// Wait for permission to re-enter the RTS with the result.
waitForReturnCapability(&cap,task);
// we might be on a different capability now... but if so, our
- // entry on the suspended_ccalling_tasks list will also have been
+ // entry on the suspended_ccalls list will also have been
// migrated.
// Remove the thread from the suspended list
recoverSuspendedTask(cap,task);
- tso = task->suspended_tso;
- task->suspended_tso = NULL;
+ tso = incall->suspended_tso;
+ incall->suspended_tso = NULL;
+ incall->suspended_cap = NULL;
tso->_link = END_TSO_QUEUE; // no write barrier reqd
- debugTrace(DEBUG_sched, "thread %lu: re-entering RTS", (unsigned long)tso->id);
+
+ traceEventRunThread(cap, tso);
- if (tso->why_blocked == BlockedOnCCall) {
- awakenBlockedExceptionQueue(cap,tso);
- tso->flags &= ~(TSO_BLOCKEX | TSO_INTERRUPTIBLE);
+ if ((tso->flags & TSO_BLOCKEX) == 0) {
+ // avoid locking the TSO if we don't have to
+ if (tso->blocked_exceptions != END_BLOCKED_EXCEPTIONS_QUEUE) {
+ awakenBlockedExceptionQueue(cap,tso);
+ }
}
/* Reset blocking status */
if (cpu == cap->no) {
appendToRunQueue(cap,tso);
} else {
- wakeupThreadOnCapability(cap, &capabilities[cpu], tso);
+ migrateThread(cap, tso, &capabilities[cpu]);
}
#else
appendToRunQueue(cap,tso);
scheduleWaitThread (StgTSO* tso, /*[out]*/HaskellObj* ret, Capability *cap)
{
Task *task;
+ StgThreadID id;
// We already created/initialised the Task
task = cap->running_task;
// This TSO is now a bound thread; make the Task and TSO
// point to each other.
- tso->bound = task;
+ tso->bound = task->incall;
tso->cap = cap;
- task->tso = tso;
- task->ret = ret;
- task->stat = NoStatus;
+ task->incall->tso = tso;
+ task->incall->ret = ret;
+ task->incall->stat = NoStatus;
appendToRunQueue(cap,tso);
- debugTrace(DEBUG_sched, "new bound thread (%lu)", (unsigned long)tso->id);
+ id = tso->id;
+ debugTrace(DEBUG_sched, "new bound thread (%lu)", (unsigned long)id);
cap = schedule(cap,task);
- ASSERT(task->stat != NoStatus);
+ ASSERT(task->incall->stat != NoStatus);
ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
- debugTrace(DEBUG_sched, "bound thread (%lu) finished", (unsigned long)task->tso->id);
+ debugTrace(DEBUG_sched, "bound thread (%lu) finished", (unsigned long)id);
return cap;
}
* ------------------------------------------------------------------------- */
#if defined(THREADED_RTS)
-void OSThreadProcAttr
-workerStart(Task *task)
+void scheduleWorker (Capability *cap, Task *task)
{
- Capability *cap;
-
- // See startWorkerTask().
- ACQUIRE_LOCK(&task->lock);
- cap = task->cap;
- RELEASE_LOCK(&task->lock);
-
- // set the thread-local pointer to the Task:
- taskEnter(task);
-
// schedule() runs without a lock.
cap = schedule(cap,task);
- // On exit from schedule(), we have a Capability.
- releaseCapability(cap);
+ // On exit from schedule(), we have a Capability, but possibly not
+ // the same one we started with.
+
+ // During shutdown, the requirement is that after all the
+ // Capabilities are shut down, all workers that are shutting down
+ // have finished workerTaskStop(). This is why we hold on to
+ // cap->lock until we've finished workerTaskStop() below.
+ //
+ // There may be workers still involved in foreign calls; those
+ // will just block in waitForReturnCapability() because the
+ // Capability has been shut down.
+ //
+ ACQUIRE_LOCK(&cap->lock);
+ releaseCapability_(cap,rtsFalse);
workerTaskStop(task);
+ RELEASE_LOCK(&cap->lock);
}
#endif
sleeping_queue = END_TSO_QUEUE;
#endif
- blackhole_queue = END_TSO_QUEUE;
-
sched_state = SCHED_RUNNING;
recent_activity = ACTIVITY_YES;
initTaskManager();
-#if defined(THREADED_RTS) || defined(PARALLEL_HASKELL)
+#if defined(THREADED_RTS)
initSparkPools();
#endif
+ RELEASE_LOCK(&sched_mutex);
+
#if defined(THREADED_RTS)
/*
* Eagerly start one worker to run each Capability, except for
for (i = 1; i < n_capabilities; i++) {
cap = &capabilities[i];
ACQUIRE_LOCK(&cap->lock);
- startWorkerTask(cap, workerStart);
+ startWorkerTask(cap);
RELEASE_LOCK(&cap->lock);
}
}
#endif
-
- trace(TRACE_sched, "start: %d capabilities", n_capabilities);
-
- RELEASE_LOCK(&sched_mutex);
}
void
-exitScheduler(
- rtsBool wait_foreign
-#if !defined(THREADED_RTS)
- __attribute__((unused))
-#endif
-)
+exitScheduler (rtsBool wait_foreign USED_IF_THREADS)
/* see Capability.c, shutdownCapability() */
{
Task *task = NULL;
-#if defined(THREADED_RTS)
- ACQUIRE_LOCK(&sched_mutex);
task = newBoundTask();
- RELEASE_LOCK(&sched_mutex);
-#endif
// If we haven't killed all the threads yet, do it now.
if (sched_state < SCHED_SHUTTING_DOWN) {
sched_state = SCHED_INTERRUPTING;
- scheduleDoGC(NULL,task,rtsFalse);
+ waitForReturnCapability(&task->cap,task);
+ scheduleDoGC(task->cap,task,rtsFalse);
+ ASSERT(task->incall->tso == NULL);
+ releaseCapability(task->cap);
}
sched_state = SCHED_SHUTTING_DOWN;
nat i;
for (i = 0; i < n_capabilities; i++) {
+ ASSERT(task->incall->tso == NULL);
shutdownCapability(&capabilities[i], task, wait_foreign);
}
- boundTaskExiting(task);
- stopTaskManager();
}
-#else
- freeCapability(&MainCapability);
#endif
+
+ boundTaskExiting(task);
}
void
freeScheduler( void )
{
- freeTaskManager();
- if (n_capabilities != 1) {
- stgFree(capabilities);
+ nat still_running;
+
+ ACQUIRE_LOCK(&sched_mutex);
+ still_running = freeTaskManager();
+ // We can only free the Capabilities if there are no Tasks still
+ // running. We might have a Task about to return from a foreign
+ // call into waitForReturnCapability(), for example (actually,
+ // this should be the *only* thing that a still-running Task can
+ // do at this point, and it will block waiting for the
+ // Capability).
+ if (still_running == 0) {
+ freeCapabilities();
+ if (n_capabilities != 1) {
+ stgFree(capabilities);
+ }
}
+ RELEASE_LOCK(&sched_mutex);
#if defined(THREADED_RTS)
closeMutex(&sched_mutex);
#endif
performGC_(rtsBool force_major)
{
Task *task;
+
// We must grab a new Task here, because the existing Task may be
// associated with a particular Capability, and chained onto the
- // suspended_ccalling_tasks queue.
- ACQUIRE_LOCK(&sched_mutex);
+ // suspended_ccalls queue.
task = newBoundTask();
- RELEASE_LOCK(&sched_mutex);
- scheduleDoGC(NULL,task,force_major);
+
+ waitForReturnCapability(&task->cap,task);
+ scheduleDoGC(task->cap,task,force_major);
+ releaseCapability(task->cap);
boundTaskExiting(task);
}
IF_DEBUG(sanity,checkTSO(tso));
- // don't allow throwTo() to modify the blocked_exceptions queue
- // while we are moving the TSO:
- lockClosure((StgClosure *)tso);
-
- if (tso->stack_size >= tso->max_stack_size && !(tso->flags & TSO_BLOCKEX)) {
+ if (tso->stack_size >= tso->max_stack_size
+ && !(tso->flags & TSO_BLOCKEX)) {
// NB. never raise a StackOverflow exception if the thread is
// inside Control.Exceptino.block. It is impractical to protect
// against stack overflow exceptions, since virtually anything
// can raise one (even 'catch'), so this is the only sensible
// thing to do here. See bug #767.
+ //
+
+ if (tso->flags & TSO_SQUEEZED) {
+ return tso;
+ }
+ // #3677: In a stack overflow situation, stack squeezing may
+ // reduce the stack size, but we don't know whether it has been
+ // reduced enough for the stack check to succeed if we try
+ // again. Fortunately stack squeezing is idempotent, so all we
+ // need to do is record whether *any* squeezing happened. If we
+ // are at the stack's absolute -K limit, and stack squeezing
+ // happened, then we try running the thread again. The
+ // TSO_SQUEEZED flag is set by threadPaused() to tell us whether
+ // squeezing happened or not.
debugTrace(DEBUG_gc,
"threadStackOverflow of TSO %ld (%p): stack too large (now %ld; max is %ld)",
tso->sp+64)));
// Send this thread the StackOverflow exception
- unlockTSO(tso);
throwToSingleThreaded(cap, tso, (StgClosure *)stackOverflow_closure);
return tso;
}
+
+ // We also want to avoid enlarging the stack if squeezing has
+ // already released some of it. However, we don't want to get into
+ // a pathalogical situation where a thread has a nearly full stack
+ // (near its current limit, but not near the absolute -K limit),
+ // keeps allocating a little bit, squeezing removes a little bit,
+ // and then it runs again. So to avoid this, if we squeezed *and*
+ // there is still less than BLOCK_SIZE_W words free, then we enlarge
+ // the stack anyway.
+ if ((tso->flags & TSO_SQUEEZED) &&
+ ((W_)(tso->sp - tso->stack) >= BLOCK_SIZE_W)) {
+ return tso;
+ }
+
/* Try to double the current stack size. If that takes us over the
* maximum stack size for this thread, then use the maximum instead
* (that is, unless we're already at or over the max size and we
"increasing stack size from %ld words to %d.",
(long)tso->stack_size, new_stack_size);
- dest = (StgTSO *)allocateLocal(cap,new_tso_size);
+ dest = (StgTSO *)allocate(cap,new_tso_size);
TICK_ALLOC_TSO(new_stack_size,0);
/* copy the TSO block and the old stack into the new area */
* of the stack, so we don't attempt to scavenge any part of the
* dead TSO's stack.
*/
- tso->what_next = ThreadRelocated;
setTSOLink(cap,tso,dest);
+ write_barrier(); // other threads seeing ThreadRelocated will look at _link
+ tso->what_next = ThreadRelocated;
tso->sp = (P_)&(tso->stack[tso->stack_size]);
tso->why_blocked = NotBlocked;
- IF_PAR_DEBUG(verbose,
- debugBelch("@@ threadStackOverflow of TSO %d (now at %p): stack size increased to %ld\n",
- tso->id, tso, tso->stack_size);
- /* If we're debugging, just print out the top of the stack */
- printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
- tso->sp+64)));
-
- unlockTSO(dest);
- unlockTSO(tso);
-
IF_DEBUG(sanity,checkTSO(dest));
#if 0
IF_DEBUG(scheduler,printTSO(dest));
}
static StgTSO *
-threadStackUnderflow (Task *task STG_UNUSED, StgTSO *tso)
+threadStackUnderflow (Capability *cap, Task *task, StgTSO *tso)
{
bdescr *bd, *new_bd;
lnat free_w, tso_size_w;
tso_size_w = tso_sizeW(tso);
- if (tso_size_w < MBLOCK_SIZE_W ||
+ if (tso_size_w < MBLOCK_SIZE_W ||
+ // TSO is less than 2 mblocks (since the first mblock is
+ // shorter than MBLOCK_SIZE_W)
+ (tso_size_w - BLOCKS_PER_MBLOCK*BLOCK_SIZE_W) % MBLOCK_SIZE_W != 0 ||
+ // or TSO is not a whole number of megablocks (ensuring
+ // precondition of splitLargeBlock() below)
+ (tso_size_w <= round_up_to_mblocks(RtsFlags.GcFlags.initialStkSize)) ||
+ // or TSO is smaller than the minimum stack size (rounded up)
(nat)(tso->stack + tso->stack_size - tso->sp) > tso->stack_size / 4)
+ // or stack is using more than 1/4 of the available space
{
+ // then do nothing
return tso;
}
- // don't allow throwTo() to modify the blocked_exceptions queue
- // while we are moving the TSO:
- lockClosure((StgClosure *)tso);
-
// this is the number of words we'll free
free_w = round_to_mblocks(tso_size_w/2);
memcpy(new_tso,tso,TSO_STRUCT_SIZE);
new_tso->stack_size = new_bd->free - new_tso->stack;
+ // The original TSO was dirty and probably on the mutable
+ // list. The new TSO is not yet on the mutable list, so we better
+ // put it there.
+ new_tso->dirty = 0;
+ new_tso->flags &= ~TSO_LINK_DIRTY;
+ dirty_TSO(cap, new_tso);
+
debugTrace(DEBUG_sched, "thread %ld: reducing TSO size from %lu words to %lu",
(long)tso->id, tso_size_w, tso_sizeW(new_tso));
- tso->what_next = ThreadRelocated;
tso->_link = new_tso; // no write barrier reqd: same generation
+ write_barrier(); // other threads seeing ThreadRelocated will look at _link
+ tso->what_next = ThreadRelocated;
// The TSO attached to this Task may have moved, so update the
// pointer to it.
- if (task->tso == tso) {
- task->tso = new_tso;
+ if (task->incall->tso == tso) {
+ task->incall->tso = new_tso;
}
- unlockTSO(new_tso);
- unlockTSO(tso);
-
IF_DEBUG(sanity,checkTSO(new_tso));
return new_tso;
{
sched_state = SCHED_INTERRUPTING;
setContextSwitches();
+#if defined(THREADED_RTS)
wakeUpRts();
+#endif
}
/* -----------------------------------------------------------------------------
will have interrupted any blocking system call in progress anyway.
-------------------------------------------------------------------------- */
-void
-wakeUpRts(void)
-{
#if defined(THREADED_RTS)
+void wakeUpRts(void)
+{
// This forces the IO Manager thread to wakeup, which will
// in turn ensure that some OS thread wakes up and runs the
// scheduler loop, which will cause a GC and deadlock check.
ioManagerWakeup();
-#endif
-}
-
-/* -----------------------------------------------------------------------------
- * checkBlackHoles()
- *
- * Check the blackhole_queue for threads that can be woken up. We do
- * this periodically: before every GC, and whenever the run queue is
- * empty.
- *
- * An elegant solution might be to just wake up all the blocked
- * threads with awakenBlockedQueue occasionally: they'll go back to
- * sleep again if the object is still a BLACKHOLE. Unfortunately this
- * doesn't give us a way to tell whether we've actually managed to
- * wake up any threads, so we would be busy-waiting.
- *
- * -------------------------------------------------------------------------- */
-
-static rtsBool
-checkBlackHoles (Capability *cap)
-{
- StgTSO **prev, *t;
- rtsBool any_woke_up = rtsFalse;
- StgHalfWord type;
-
- // blackhole_queue is global:
- ASSERT_LOCK_HELD(&sched_mutex);
-
- debugTrace(DEBUG_sched, "checking threads blocked on black holes");
-
- // ASSUMES: sched_mutex
- prev = &blackhole_queue;
- t = blackhole_queue;
- while (t != END_TSO_QUEUE) {
- ASSERT(t->why_blocked == BlockedOnBlackHole);
- type = get_itbl(UNTAG_CLOSURE(t->block_info.closure))->type;
- if (type != BLACKHOLE && type != CAF_BLACKHOLE) {
- IF_DEBUG(sanity,checkTSO(t));
- t = unblockOne(cap, t);
- *prev = t;
- any_woke_up = rtsTrue;
- } else {
- prev = &t->_link;
- t = t->_link;
- }
- }
-
- return any_woke_up;
}
+#endif
/* -----------------------------------------------------------------------------
Deleting threads
-------------------------------------------------------------------------- */
static void
-deleteThread (Capability *cap, StgTSO *tso)
+deleteThread (Capability *cap STG_UNUSED, StgTSO *tso)
{
// NOTE: must only be called on a TSO that we have exclusive
// access to, because we will call throwToSingleThreaded() below.
// we must own all Capabilities.
if (tso->why_blocked != BlockedOnCCall &&
- tso->why_blocked != BlockedOnCCall_NoUnblockExc) {
- throwToSingleThreaded(cap,tso,NULL);
+ tso->why_blocked != BlockedOnCCall_Interruptible) {
+ throwToSingleThreaded(tso->cap,tso,NULL);
}
}
// like deleteThread(), but we delete threads in foreign calls, too.
if (tso->why_blocked == BlockedOnCCall ||
- tso->why_blocked == BlockedOnCCall_NoUnblockExc) {
- unblockOne(cap,tso);
+ tso->why_blocked == BlockedOnCCall_Interruptible) {
tso->what_next = ThreadKilled;
+ appendToRunQueue(tso->cap, tso);
} else {
deleteThread(cap,tso);
}
// Only create raise_closure if we need to.
if (raise_closure == NULL) {
raise_closure =
- (StgThunk *)allocateLocal(cap,sizeofW(StgThunk)+1);
+ (StgThunk *)allocate(cap,sizeofW(StgThunk)+1);
SET_HDR(raise_closure, &stg_raise_info, CCCS);
raise_closure->payload[0] = exception;
}
- UPD_IND(((StgUpdateFrame *)p)->updatee,(StgClosure *)raise_closure);
+ updateThunk(cap, tso, ((StgUpdateFrame *)p)->updatee,
+ (StgClosure *)raise_closure);
p = next;
continue;
case CATCH_STM_FRAME: {
StgTRecHeader *trec = tso -> trec;
- StgTRecHeader *outer = stmGetEnclosingTRec(trec);
+ StgTRecHeader *outer = trec -> enclosing_trec;
debugTrace(DEBUG_stm,
"found CATCH_STM_FRAME at %p during retry", p);
debugTrace(DEBUG_stm, "trec=%p outer=%p", trec, outer);
{
StgTSO *tso, *next;
Capability *cap;
- step *step;
+ generation *gen;
for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
next = tso->global_link;
- step = Bdescr((P_)tso)->step;
- tso->global_link = step->threads;
- step->threads = tso;
+ gen = Bdescr((P_)tso)->gen;
+ tso->global_link = gen->threads;
+ gen->threads = tso;
debugTrace(DEBUG_sched, "resurrecting thread %lu", (unsigned long)tso->id);
switch (tso->why_blocked) {
case BlockedOnMVar:
- case BlockedOnException:
/* Called by GC - sched_mutex lock is currently held. */
throwToSingleThreaded(cap, tso,
- (StgClosure *)blockedOnDeadMVar_closure);
+ (StgClosure *)blockedIndefinitelyOnMVar_closure);
break;
case BlockedOnBlackHole:
throwToSingleThreaded(cap, tso,
break;
case BlockedOnSTM:
throwToSingleThreaded(cap, tso,
- (StgClosure *)blockedIndefinitely_closure);
+ (StgClosure *)blockedIndefinitelyOnSTM_closure);
break;
case NotBlocked:
/* This might happen if the thread was blocked on a black hole
* can wake up threads, remember...).
*/
continue;
+ case BlockedOnMsgThrowTo:
+ // This can happen if the target is masking, blocks on a
+ // black hole, and then is found to be unreachable. In
+ // this case, we want to let the target wake up and carry
+ // on, and do nothing to this thread.
+ continue;
default:
- barf("resurrectThreads: thread blocked in a strange way");
+ barf("resurrectThreads: thread blocked in a strange way: %d",
+ tso->why_blocked);
}
}
}
-
-/* -----------------------------------------------------------------------------
- performPendingThrowTos is called after garbage collection, and
- passed a list of threads that were found to have pending throwTos
- (tso->blocked_exceptions was not empty), and were blocked.
- Normally this doesn't happen, because we would deliver the
- exception directly if the target thread is blocked, but there are
- small windows where it might occur on a multiprocessor (see
- throwTo()).
-
- NB. we must be holding all the capabilities at this point, just
- like resurrectThreads().
- -------------------------------------------------------------------------- */
-
-void
-performPendingThrowTos (StgTSO *threads)
-{
- StgTSO *tso, *next;
- Capability *cap;
- step *step;
-
- for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
- next = tso->global_link;
-
- step = Bdescr((P_)tso)->step;
- tso->global_link = step->threads;
- step->threads = tso;
-
- debugTrace(DEBUG_sched, "performing blocked throwTo to thread %lu", (unsigned long)tso->id);
-
- cap = tso->cap;
- maybePerformBlockedException(cap, tso);
- }
-}
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