* --------------------------------------------------------------------------*/
#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 "Stats.h"
#include "STM.h"
-#include "Timer.h"
#include "Prelude.h"
#include "ThreadLabels.h"
-#include "LdvProfile.h"
#include "Updates.h"
-#ifdef PROFILING
#include "Proftimer.h"
#include "ProfHeap.h"
-#endif
-#if defined(GRAN) || defined(PARALLEL_HASKELL)
-# include "GranSimRts.h"
-# include "GranSim.h"
-# include "ParallelRts.h"
-# include "Parallel.h"
-# include "ParallelDebug.h"
-# include "FetchMe.h"
-# include "HLC.h"
-#endif
+#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"
#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
* -------------------------------------------------------------------------- */
-#if defined(GRAN)
-
-StgTSO* ActiveTSO = NULL; /* for assigning system costs; GranSim-Light only */
-/* rtsTime TimeOfNextEvent, EndOfTimeSlice; now in GranSim.c */
-
-/*
- In GranSim we have a runnable and a blocked queue for each processor.
- In order to minimise code changes new arrays run_queue_hds/tls
- are created. run_queue_hd is then a short cut (macro) for
- run_queue_hds[CurrentProc] (see GranSim.h).
- -- HWL
-*/
-StgTSO *run_queue_hds[MAX_PROC], *run_queue_tls[MAX_PROC];
-StgTSO *blocked_queue_hds[MAX_PROC], *blocked_queue_tls[MAX_PROC];
-StgTSO *ccalling_threadss[MAX_PROC];
-/* We use the same global list of threads (all_threads) in GranSim as in
- the std RTS (i.e. we are cheating). However, we don't use this list in
- the GranSim specific code at the moment (so we are only potentially
- cheating). */
-
-#else /* !GRAN */
-
#if !defined(THREADED_RTS)
// Blocked/sleeping thrads
StgTSO *blocked_queue_hd = NULL;
* LOCK: sched_mutex+capability, or all capabilities
*/
StgTSO *blackhole_queue = NULL;
-#endif
/* The blackhole_queue should be checked for threads to wake up. See
* Schedule.h for more thorough comment.
*/
rtsBool blackholes_need_checking = rtsFalse;
-/* Linked list of all threads.
- * Used for detecting garbage collected threads.
- * LOCK: sched_mutex+capability, or all capabilities
- */
-StgTSO *all_threads = NULL;
-
-/* flag set by signal handler to precipitate a context switch
- * LOCK: none (just an advisory flag)
+/* 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.)
*/
-int context_switch = 0;
+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;
-
-#if defined(GRAN)
-StgTSO *CurrentTSO;
-#endif
+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.
Mutex sched_mutex;
#endif
-#if defined(PARALLEL_HASKELL)
-StgTSO *LastTSO;
-rtsTime TimeOfLastYield;
-rtsBool emitSchedule = rtsTrue;
-#endif
-
#if !defined(mingw32_HOST_OS)
#define FORKPROCESS_PRIMOP_SUPPORTED
#endif
// scheduler clearer.
//
static void schedulePreLoop (void);
+static void scheduleFindWork (Capability *cap);
#if defined(THREADED_RTS)
-static void schedulePushWork(Capability *cap, Task *task);
+static void scheduleYield (Capability **pcap, Task *task, rtsBool);
#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 scheduleDetectDeadlock (Capability *cap, Task *task);
-#if defined(GRAN)
-static StgTSO *scheduleProcessEvent(rtsEvent *event);
-#endif
-#if defined(PARALLEL_HASKELL)
-static StgTSO *scheduleSendPendingMessages(void);
-static void scheduleActivateSpark(void);
-static rtsBool scheduleGetRemoteWork(rtsBool *receivedFinish);
-#endif
-#if defined(PAR) || defined(GRAN)
-static void scheduleGranParReport(void);
+static void schedulePushWork(Capability *cap, Task *task);
+#if defined(THREADED_RTS)
+static void scheduleActivateSpark(Capability *cap);
#endif
-static void schedulePostRunThread(void);
+static void schedulePostRunThread(Capability *cap, StgTSO *t);
static rtsBool scheduleHandleHeapOverflow( Capability *cap, StgTSO *t );
static void scheduleHandleStackOverflow( Capability *cap, Task *task,
StgTSO *t);
static void scheduleHandleThreadBlocked( StgTSO *t );
static rtsBool scheduleHandleThreadFinished( Capability *cap, Task *task,
StgTSO *t );
-static rtsBool scheduleDoHeapProfile(rtsBool ready_to_gc);
+static rtsBool scheduleNeedHeapProfile(rtsBool ready_to_gc);
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 void deleteThread (Capability *cap, StgTSO *tso);
static void deleteAllThreads (Capability *cap);
static void deleteThread_(Capability *cap, StgTSO *tso);
#endif
-#if defined(PARALLEL_HASKELL)
-StgTSO * createSparkThread(rtsSpark spark);
-StgTSO * activateSpark (rtsSpark spark);
-#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
}
/* ---------------------------------------------------------------------------
This revolves around the global event queue, which determines what
to do next. Therefore, it's more complicated than either the
concurrent or the parallel (GUM) setup.
+ This version has been entirely removed (JB 2008/08).
GUM version:
GUM iterates over incoming messages.
(see PendingFetches).
This is not the ugliest code you could imagine, but it's bloody close.
+ (JB 2008/08) This version was formerly indicated by a PP-Flag PAR,
+ now by PP-flag PARALLEL_HASKELL. The Eden RTS (in GHC-6.x) uses it,
+ as well as future GUM versions. This file has been refurbished to
+ only contain valid code, which is however incomplete, refers to
+ invalid includes etc.
+
------------------------------------------------------------------------ */
static Capability *
StgTSO *t;
Capability *cap;
StgThreadReturnCode ret;
-#if defined(GRAN)
- rtsEvent *event;
-#elif defined(PARALLEL_HASKELL)
- StgTSO *tso;
- GlobalTaskId pe;
- rtsBool receivedFinish = rtsFalse;
-# if defined(DEBUG)
- nat tp_size, sp_size; // stats only
-# endif
-#endif
nat prev_what_next;
rtsBool ready_to_gc;
#if defined(THREADED_RTS)
rtsBool first = rtsTrue;
+ rtsBool force_yield = rtsFalse;
#endif
cap = initialCapability;
// 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)
-#elif defined(GRAN)
-#define TERMINATION_CONDITION ((event = get_next_event()) != (rtsEvent*)NULL)
-#else
-#define TERMINATION_CONDITION rtsTrue
-#endif
-
- while (TERMINATION_CONDITION) {
-
-#if defined(GRAN)
- /* Choose the processor with the next event */
- CurrentProc = event->proc;
- CurrentTSO = event->tso;
-#endif
-
-#if defined(THREADED_RTS)
- if (first) {
- // don't yield the first time, we want a chance to run this
- // thread for a bit, even if there are others banging at the
- // door.
- first = rtsFalse;
- ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
- } else {
- // Yield the capability to higher-priority tasks if necessary.
- yieldCapability(&cap, task);
- }
-#endif
-
-#if defined(THREADED_RTS)
- schedulePushWork(cap,task);
-#endif
+ 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
barf("sched_state: %d", sched_state);
}
-#if defined(THREADED_RTS)
- // If the run queue is empty, take a spark and turn it into a thread.
- {
- if (emptyRunQueue(cap)) {
- StgClosure *spark;
- spark = findSpark(cap);
- if (spark != NULL) {
- debugTrace(DEBUG_sched,
- "turning spark of closure %p into a thread",
- (StgClosure *)spark);
- createSparkThread(cap,spark);
- }
- }
- }
-#endif // THREADED_RTS
-
- 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); }
+ scheduleFindWork(cap);
- scheduleCheckWakeupThreads(cap);
-
- scheduleCheckBlockedThreads(cap);
+ /* work pushing, currently relevant only for THREADED_RTS:
+ (pushes threads, wakes up idle capabilities for stealing) */
+ schedulePushWork(cap,task);
scheduleDetectDeadlock(cap,task);
+
#if defined(THREADED_RTS)
cap = task->cap; // reload cap, it might have changed
#endif
//
// win32: might be here due to awaitEvent() being abandoned
// as a result of a console event having been delivered.
- if ( emptyRunQueue(cap) ) {
-#if !defined(THREADED_RTS) && !defined(mingw32_HOST_OS)
- ASSERT(sched_state >= SCHED_INTERRUPTING);
-#endif
- continue; // nothing to do
+
+#if defined(THREADED_RTS)
+ if (first)
+ {
+ // XXX: ToDo
+ // // don't yield the first time, we want a chance to run this
+ // // thread for a bit, even if there are others banging at the
+ // // door.
+ // first = rtsFalse;
+ // ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
}
-#if defined(PARALLEL_HASKELL)
- scheduleSendPendingMessages();
- if (emptyRunQueue(cap) && scheduleActivateSpark())
- continue;
+ yield:
+ scheduleYield(&cap,task,force_yield);
+ force_yield = rtsFalse;
-#if defined(SPARKS)
- ASSERT(next_fish_to_send_at==0); // i.e. no delayed fishes left!
+ if (emptyRunQueue(cap)) continue; // look for work again
#endif
- /* If we still have no work we need to send a FISH to get a spark
- from another PE */
- if (emptyRunQueue(cap)) {
- if (!scheduleGetRemoteWork(&receivedFinish)) continue;
- ASSERT(rtsFalse); // should not happen at the moment
- }
- // from here: non-empty run queue.
- // TODO: merge above case with this, only one call processMessages() !
- if (PacketsWaiting()) { /* process incoming messages, if
- any pending... only in else
- because getRemoteWork waits for
- messages as well */
- receivedFinish = processMessages();
+#if !defined(THREADED_RTS) && !defined(mingw32_HOST_OS)
+ if ( emptyRunQueue(cap) ) {
+ ASSERT(sched_state >= SCHED_INTERRUPTING);
}
#endif
-#if defined(GRAN)
- scheduleProcessEvent(event);
-#endif
-
//
// Get a thread to run
//
t = popRunQueue(cap);
-#if defined(GRAN) || defined(PAR)
- scheduleGranParReport(); // some kind of debuging output
-#else
// Sanity check the thread we're about to run. This can be
// expensive if there is lots of thread switching going on...
IF_DEBUG(sanity,checkTSO(t));
-#endif
#if defined(THREADED_RTS)
// Check whether we can run this thread in the current task.
if (bound) {
if (bound == task) {
- debugTrace(DEBUG_sched,
- "### Running thread %lu in bound thread", (unsigned long)t->id);
// 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;
// The thread we want to run is unbound.
if (task->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
- cap->r.rCurrentTSO = t;
-
+ // 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
*/
if (RtsFlags.ConcFlags.ctxtSwitchTicks == 0
&& !emptyThreadQueues(cap)) {
- context_switch = 1;
+ cap->context_switch = 1;
}
run_thread:
- debugTrace(DEBUG_sched, "-->> running thread %ld %s ...",
- (long)t->id, whatNext_strs[t->what_next]);
+ // CurrentTSO is the thread to run. t might be different if we
+ // loop back to run_thread, so make sure to set CurrentTSO after
+ // that.
+ cap->r.rCurrentTSO = t;
-#if defined(PROFILING)
startHeapProfTimer();
-#endif
// Check for exceptions blocked on this thread
maybePerformBlockedException (cap, t);
ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task);
ASSERT(t->cap == cap);
+ ASSERT(t->bound ? t->bound->cap == cap : 1);
prev_what_next = t->what_next;
cap->in_haskell = rtsTrue;
- dirtyTSO(t);
+ dirty_TSO(cap,t);
- recent_activity = ACTIVITY_YES;
+#if defined(THREADED_RTS)
+ if (recent_activity == ACTIVITY_DONE_GC) {
+ // ACTIVITY_DONE_GC means we turned off the timer signal to
+ // conserve power (see #1623). Re-enable it here.
+ nat prev;
+ prev = xchg((P_)&recent_activity, ACTIVITY_YES);
+ if (prev == ACTIVITY_DONE_GC) {
+ startTimer();
+ }
+ } else {
+ recent_activity = ACTIVITY_YES;
+ }
+#endif
+
+ traceSchedEvent(cap, EVENT_RUN_THREAD, t, 0);
switch (prev_what_next) {
t->saved_winerror = GetLastError();
#endif
+ traceSchedEvent (cap, EVENT_STOP_THREAD, t, ret);
+
#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
// 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;
+ force_yield = rtsTrue;
+ goto yield;
}
#endif
// ----------------------------------------------------------------------
// Costs for the scheduler are assigned to CCS_SYSTEM
-#if defined(PROFILING)
stopHeapProfTimer();
+#if defined(PROFILING)
CCCS = CCS_SYSTEM;
#endif
- schedulePostRunThread();
+ schedulePostRunThread(cap,t);
+
+ if (ret != StackOverflow) {
+ t = threadStackUnderflow(task,t);
+ }
ready_to_gc = rtsFalse;
barf("schedule: invalid thread return code %d", (int)ret);
}
- if (scheduleDoHeapProfile(ready_to_gc)) { ready_to_gc = rtsFalse; }
- if (ready_to_gc) {
+ if (ready_to_gc || scheduleNeedHeapProfile(ready_to_gc)) {
cap = scheduleDoGC(cap,task,rtsFalse);
}
} /* end of while() */
-
- debugTrace(PAR_DEBUG_verbose,
- "== Leaving schedule() after having received Finish");
}
/* ----------------------------------------------------------------------------
static void
schedulePreLoop(void)
{
-#if defined(GRAN)
- /* set up first event to get things going */
- /* ToDo: assign costs for system setup and init MainTSO ! */
- new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
- ContinueThread,
- CurrentTSO, (StgClosure*)NULL, (rtsSpark*)NULL);
-
- debugTrace (DEBUG_gran,
- "GRAN: Init CurrentTSO (in schedule) = %p",
- CurrentTSO);
- IF_DEBUG(gran, G_TSO(CurrentTSO, 5));
-
- if (RtsFlags.GranFlags.Light) {
- /* Save current time; GranSim Light only */
- CurrentTSO->gran.clock = CurrentTime[CurrentProc];
- }
+ // initialisation for scheduler - what cannot go into initScheduler()
+}
+
+/* -----------------------------------------------------------------------------
+ * scheduleFindWork()
+ *
+ * Search for work to do, and handle messages from elsewhere.
+ * -------------------------------------------------------------------------- */
+
+static void
+scheduleFindWork (Capability *cap)
+{
+ 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);
+
+ scheduleCheckBlockedThreads(cap);
+
+#if defined(THREADED_RTS)
+ if (emptyRunQueue(cap)) { scheduleActivateSpark(cap); }
#endif
}
+#if defined(THREADED_RTS)
+STATIC_INLINE rtsBool
+shouldYieldCapability (Capability *cap, Task *task)
+{
+ // we need to yield this capability to someone else if..
+ // - another thread is initiating a GC
+ // - another Task is returning from a foreign call
+ // - the thread at the head of the run queue cannot be run
+ // by this Task (it is bound to another Task, or it is unbound
+ // and this task it bound).
+ return (waiting_for_gc ||
+ cap->returning_tasks_hd != NULL ||
+ (!emptyRunQueue(cap) && (task->tso == NULL
+ ? cap->run_queue_hd->bound != NULL
+ : cap->run_queue_hd->bound != task)));
+}
+
+// This is the single place where a Task goes to sleep. There are
+// two reasons it might need to sleep:
+// - there are no threads to run
+// - we need to yield this Capability to someone else
+// (see shouldYieldCapability())
+//
+// 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, rtsBool force_yield)
+{
+ Capability *cap = *pcap;
+
+ // if we have work, and we don't need to give up the Capability, continue.
+ //
+ // The force_yield flag is used when a bound thread blocks. This
+ // is a particularly tricky situation: the current Task does not
+ // own the TSO any more, since it is on some queue somewhere, and
+ // might be woken up or manipulated by another thread at any time.
+ // The TSO and Task might be migrated to another Capability.
+ // Certain invariants might be in doubt, such as task->bound->cap
+ // == cap. We have to yield the current Capability immediately,
+ // no messing around.
+ //
+ if (!force_yield &&
+ !shouldYieldCapability(cap,task) &&
+ (!emptyRunQueue(cap) ||
+ !emptyWakeupQueue(cap) ||
+ blackholes_need_checking ||
+ sched_state >= SCHED_INTERRUPTING))
+ return;
+
+ // otherwise yield (sleep), and keep yielding if necessary.
+ do {
+ yieldCapability(&cap,task);
+ }
+ while (shouldYieldCapability(cap,task));
+
+ // note there may still be no threads on the run queue at this
+ // point, the caller has to check.
+
+ *pcap = cap;
+ return;
+}
+#endif
+
/* -----------------------------------------------------------------------------
* schedulePushWork()
*
* Push work to other Capabilities if we have some.
* -------------------------------------------------------------------------- */
-#if defined(THREADED_RTS)
static void
schedulePushWork(Capability *cap USED_IF_THREADS,
Task *task USED_IF_THREADS)
{
+ /* following code not for PARALLEL_HASKELL. I kept the call general,
+ future GUM versions might use pushing in a distributed setup */
+#if defined(THREADED_RTS)
+
Capability *free_caps[n_capabilities], *cap0;
nat i, n_free_caps;
// 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.
StgTSO *prev, *t, *next;
rtsBool pushed_to_all;
- debugTrace(DEBUG_sched, "excess threads on run queue and %d free capabilities, sharing...", n_free_caps);
+ debugTrace(DEBUG_sched,
+ "cap %d: %s and %d free capabilities, sharing...",
+ cap->no,
+ (!emptyRunQueue(cap) && cap->run_queue_hd->_link != END_TSO_QUEUE)?
+ "excess threads on run queue":"sparks to share (>=2)",
+ n_free_caps);
i = 0;
pushed_to_all = rtsFalse;
if (cap->run_queue_hd != END_TSO_QUEUE) {
prev = cap->run_queue_hd;
- t = prev->link;
- prev->link = END_TSO_QUEUE;
+ t = prev->_link;
+ prev->_link = END_TSO_QUEUE;
for (; t != END_TSO_QUEUE; t = next) {
- next = t->link;
- t->link = END_TSO_QUEUE;
+ next = t->_link;
+ t->_link = END_TSO_QUEUE;
if (t->what_next == ThreadRelocated
|| t->bound == task // don't move my bound thread
|| tsoLocked(t)) { // don't move a locked thread
- prev->link = t;
+ setTSOLink(cap, prev, t);
prev = t;
} else if (i == n_free_caps) {
pushed_to_all = rtsTrue;
i = 0;
// keep one for us
- prev->link = t;
+ setTSOLink(cap, prev, t);
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);
+
+ traceSchedEvent (cap, EVENT_MIGRATE_THREAD, t, free_caps[i]->no);
+
if (t->bound) { t->bound->cap = free_caps[i]; }
t->cap = free_caps[i];
i++;
cap->run_queue_tl = prev;
}
+#ifdef SPARK_PUSHING
+ /* JB I left this code in place, it would work but is not necessary */
+
// If there are some free capabilities that we didn't push any
// threads to, then try to push a spark to each one.
if (!pushed_to_all) {
// i is the next free capability to push to
for (; i < n_free_caps; i++) {
if (emptySparkPoolCap(free_caps[i])) {
- spark = findSpark(cap);
+ spark = tryStealSpark(cap->sparks);
if (spark != NULL) {
debugTrace(DEBUG_sched, "pushing spark %p to capability %d", spark, free_caps[i]->no);
+
+ traceSchedEvent(free_caps[i], EVENT_STEAL_SPARK, t, cap->no);
+
newSpark(&(free_caps[i]->r), spark);
}
}
}
}
+#endif /* SPARK_PUSHING */
// release the capabilities
for (i = 0; i < n_free_caps; i++) {
task->cap = free_caps[i];
- releaseCapability(free_caps[i]);
+ releaseAndWakeupCapability(free_caps[i]);
}
}
task->cap = cap; // reset to point to our Capability.
+
+#endif /* THREADED_RTS */
+
}
-#endif
/* ----------------------------------------------------------------------------
* Start any pending signal handlers
static void
scheduleStartSignalHandlers(Capability *cap)
{
- if (signals_pending()) { // safe outside the lock
+ if (RtsFlags.MiscFlags.install_signal_handlers && signals_pending()) {
+ // safe outside the lock
startSignalHandlers(cap);
}
}
cap->run_queue_hd = cap->wakeup_queue_hd;
cap->run_queue_tl = cap->wakeup_queue_tl;
} else {
- cap->run_queue_tl->link = cap->wakeup_queue_hd;
+ 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;
{
ACQUIRE_LOCK(&sched_mutex);
if ( blackholes_need_checking ) {
- checkBlackHoles(cap);
blackholes_need_checking = rtsFalse;
+ // important that we reset the flag *before* checking the
+ // blackhole queue, otherwise we could get deadlock. This
+ // happens as follows: we wake up a thread that
+ // immediately runs on another Capability, blocks on a
+ // blackhole, and then we reset the blackholes_need_checking flag.
+ checkBlackHoles(cap);
}
RELEASE_LOCK(&sched_mutex);
}
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;
-
if ( !emptyRunQueue(cap) ) return;
#if defined(RTS_USER_SIGNALS) && !defined(THREADED_RTS)
* for signals to arrive rather then bombing out with a
* deadlock.
*/
- if ( anyUserHandlers() ) {
+ if ( RtsFlags.MiscFlags.install_signal_handlers && anyUserHandlers() ) {
debugTrace(DEBUG_sched,
"still deadlocked, waiting for signals...");
// either we have threads to run, or we were interrupted:
ASSERT(!emptyRunQueue(cap) || sched_state >= SCHED_INTERRUPTING);
+
+ return;
}
#endif
case BlockedOnException:
case BlockedOnMVar:
throwToSingleThreaded(cap, task->tso,
- (StgClosure *)NonTermination_closure);
+ (StgClosure *)nonTermination_closure);
return;
default:
barf("deadlock: main thread blocked in a strange way");
}
}
-/* ----------------------------------------------------------------------------
- * Process an event (GRAN only)
- * ------------------------------------------------------------------------- */
-
-#if defined(GRAN)
-static StgTSO *
-scheduleProcessEvent(rtsEvent *event)
-{
- StgTSO *t;
-
- if (RtsFlags.GranFlags.Light)
- GranSimLight_enter_system(event, &ActiveTSO); // adjust ActiveTSO etc
-
- /* adjust time based on time-stamp */
- if (event->time > CurrentTime[CurrentProc] &&
- event->evttype != ContinueThread)
- CurrentTime[CurrentProc] = event->time;
-
- /* Deal with the idle PEs (may issue FindWork or MoveSpark events) */
- if (!RtsFlags.GranFlags.Light)
- handleIdlePEs();
-
- IF_DEBUG(gran, debugBelch("GRAN: switch by event-type\n"));
-
- /* main event dispatcher in GranSim */
- switch (event->evttype) {
- /* Should just be continuing execution */
- case ContinueThread:
- IF_DEBUG(gran, debugBelch("GRAN: doing ContinueThread\n"));
- /* ToDo: check assertion
- ASSERT(run_queue_hd != (StgTSO*)NULL &&
- run_queue_hd != END_TSO_QUEUE);
- */
- /* Ignore ContinueThreads for fetching threads (if synchr comm) */
- if (!RtsFlags.GranFlags.DoAsyncFetch &&
- procStatus[CurrentProc]==Fetching) {
- debugBelch("ghuH: Spurious ContinueThread while Fetching ignored; TSO %d (%p) [PE %d]\n",
- CurrentTSO->id, CurrentTSO, CurrentProc);
- goto next_thread;
- }
- /* Ignore ContinueThreads for completed threads */
- if (CurrentTSO->what_next == ThreadComplete) {
- debugBelch("ghuH: found a ContinueThread event for completed thread %d (%p) [PE %d] (ignoring ContinueThread)\n",
- CurrentTSO->id, CurrentTSO, CurrentProc);
- goto next_thread;
- }
- /* Ignore ContinueThreads for threads that are being migrated */
- if (PROCS(CurrentTSO)==Nowhere) {
- debugBelch("ghuH: trying to run the migrating TSO %d (%p) [PE %d] (ignoring ContinueThread)\n",
- CurrentTSO->id, CurrentTSO, CurrentProc);
- goto next_thread;
- }
- /* The thread should be at the beginning of the run queue */
- if (CurrentTSO!=run_queue_hds[CurrentProc]) {
- debugBelch("ghuH: TSO %d (%p) [PE %d] is not at the start of the run_queue when doing a ContinueThread\n",
- CurrentTSO->id, CurrentTSO, CurrentProc);
- break; // run the thread anyway
- }
- /*
- new_event(proc, proc, CurrentTime[proc],
- FindWork,
- (StgTSO*)NULL, (StgClosure*)NULL, (rtsSpark*)NULL);
- goto next_thread;
- */ /* Catches superfluous CONTINUEs -- should be unnecessary */
- break; // now actually run the thread; DaH Qu'vam yImuHbej
-
- case FetchNode:
- do_the_fetchnode(event);
- goto next_thread; /* handle next event in event queue */
-
- case GlobalBlock:
- do_the_globalblock(event);
- goto next_thread; /* handle next event in event queue */
-
- case FetchReply:
- do_the_fetchreply(event);
- goto next_thread; /* handle next event in event queue */
-
- case UnblockThread: /* Move from the blocked queue to the tail of */
- do_the_unblock(event);
- goto next_thread; /* handle next event in event queue */
-
- case ResumeThread: /* Move from the blocked queue to the tail of */
- /* the runnable queue ( i.e. Qu' SImqa'lu') */
- event->tso->gran.blocktime +=
- CurrentTime[CurrentProc] - event->tso->gran.blockedat;
- do_the_startthread(event);
- goto next_thread; /* handle next event in event queue */
-
- case StartThread:
- do_the_startthread(event);
- goto next_thread; /* handle next event in event queue */
-
- case MoveThread:
- do_the_movethread(event);
- goto next_thread; /* handle next event in event queue */
-
- case MoveSpark:
- do_the_movespark(event);
- goto next_thread; /* handle next event in event queue */
-
- case FindWork:
- do_the_findwork(event);
- goto next_thread; /* handle next event in event queue */
-
- default:
- barf("Illegal event type %u\n", event->evttype);
- } /* switch */
-
- /* This point was scheduler_loop in the old RTS */
-
- IF_DEBUG(gran, debugBelch("GRAN: after main switch\n"));
-
- TimeOfLastEvent = CurrentTime[CurrentProc];
- TimeOfNextEvent = get_time_of_next_event();
- IgnoreEvents=(TimeOfNextEvent==0); // HWL HACK
- // CurrentTSO = ThreadQueueHd;
-
- IF_DEBUG(gran, debugBelch("GRAN: time of next event is: %ld\n",
- TimeOfNextEvent));
-
- if (RtsFlags.GranFlags.Light)
- GranSimLight_leave_system(event, &ActiveTSO);
-
- EndOfTimeSlice = CurrentTime[CurrentProc]+RtsFlags.GranFlags.time_slice;
-
- IF_DEBUG(gran,
- debugBelch("GRAN: end of time-slice is %#lx\n", EndOfTimeSlice));
-
- /* in a GranSim setup the TSO stays on the run queue */
- t = CurrentTSO;
- /* Take a thread from the run queue. */
- POP_RUN_QUEUE(t); // take_off_run_queue(t);
-
- IF_DEBUG(gran,
- debugBelch("GRAN: About to run current thread, which is\n");
- G_TSO(t,5));
-
- context_switch = 0; // turned on via GranYield, checking events and time slice
-
- IF_DEBUG(gran,
- DumpGranEvent(GR_SCHEDULE, t));
-
- procStatus[CurrentProc] = Busy;
-}
-#endif // GRAN
/* ----------------------------------------------------------------------------
* Send pending messages (PARALLEL_HASKELL only)
* ------------------------------------------------------------------------- */
#if defined(PARALLEL_HASKELL)
-static StgTSO *
+static void
scheduleSendPendingMessages(void)
{
- StgSparkPool *pool;
- rtsSpark spark;
- StgTSO *t;
# if defined(PAR) // global Mem.Mgmt., omit for now
if (PendingFetches != END_BF_QUEUE) {
#endif
/* ----------------------------------------------------------------------------
- * Activate spark threads (PARALLEL_HASKELL only)
+ * Activate spark threads (PARALLEL_HASKELL and THREADED_RTS)
* ------------------------------------------------------------------------- */
-#if defined(PARALLEL_HASKELL)
-static void
-scheduleActivateSpark(void)
-{
-#if defined(SPARKS)
- ASSERT(emptyRunQueue());
-/* We get here if the run queue is empty and 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.
-*/
-
- /* :-[ no local threads => look out for local sparks */
- /* the spark pool for the current PE */
- pool = &(cap.r.rSparks); // JB: cap = (old) MainCap
- if (advisory_thread_count < RtsFlags.ParFlags.maxThreads &&
- pool->hd < pool->tl) {
- /*
- * ToDo: add GC code check that we really have enough heap afterwards!!
- * Old comment:
- * If we're here (no runnable threads) and we have pending
- * sparks, we must have a space problem. Get enough space
- * to turn one of those pending sparks into a
- * thread...
- */
-
- spark = findSpark(rtsFalse); /* get a spark */
- if (spark != (rtsSpark) NULL) {
- tso = createThreadFromSpark(spark); /* turn the spark into a thread */
- IF_PAR_DEBUG(fish, // schedule,
- debugBelch("==== schedule: Created TSO %d (%p); %d threads active\n",
- tso->id, tso, advisory_thread_count));
-
- if (tso==END_TSO_QUEUE) { /* failed to activate spark->back to loop */
- IF_PAR_DEBUG(fish, // schedule,
- debugBelch("==^^ failed to create thread from spark @ %lx\n",
- spark));
- return rtsFalse; /* failed to generate a thread */
- } /* otherwise fall through & pick-up new tso */
- } else {
- IF_PAR_DEBUG(fish, // schedule,
- debugBelch("==^^ no local sparks (spark pool contains only NFs: %d)\n",
- spark_queue_len(pool)));
- return rtsFalse; /* failed to generate a thread */
- }
- return rtsTrue; /* success in generating a thread */
- } else { /* no more threads permitted or pool empty */
- return rtsFalse; /* failed to generateThread */
- }
-#else
- tso = NULL; // avoid compiler warning only
- return rtsFalse; /* dummy in non-PAR setup */
-#endif // SPARKS
-}
-#endif // PARALLEL_HASKELL
-
-/* ----------------------------------------------------------------------------
- * Get work from a remote node (PARALLEL_HASKELL only)
- * ------------------------------------------------------------------------- */
-
-#if defined(PARALLEL_HASKELL)
-static rtsBool
-scheduleGetRemoteWork(rtsBool *receivedFinish)
-{
- ASSERT(emptyRunQueue());
-
- 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
- }
- }
-# ifndef SPARKS
- //++EDEN++ idle() , i.e. send all buffers, wait for work
- // suppress fishing in EDEN... just look for incoming messages
- // (blocking receive)
- IF_PAR_DEBUG(verbose,
- debugBelch("...wait for incoming messages...\n"));
- *receivedFinish = processMessages(); // blocking receive...
-
- // and reenter scheduling loop after having received something
- // (return rtsFalse below)
-
-# else /* activate SPARKS machinery */
-/* We get here, if we have no work, tried to activate a local spark, but still
- have no work. We try to get a remote spark, by sending a FISH message.
- Thread migration should be added here, and triggered when a sequence of
- fishes returns without work. */
- delay = (RtsFlags.ParFlags.fishDelay!=0ll ? RtsFlags.ParFlags.fishDelay : 0ll);
-
- /* =8-[ no local sparks => look for work on other PEs */
- /*
- * We really have absolutely no work. Send out a fish
- * (there may be some out there already), and wait for
- * something to arrive. We clearly can't run any threads
- * until a SCHEDULE or RESUME arrives, and so that's what
- * we're hoping to see. (Of course, we still have to
- * respond to other types of messages.)
- */
- rtsTime now = msTime() /*CURRENT_TIME*/;
- IF_PAR_DEBUG(verbose,
- debugBelch("-- now=%ld\n", now));
- IF_PAR_DEBUG(fish, // verbose,
- if (outstandingFishes < RtsFlags.ParFlags.maxFishes &&
- (last_fish_arrived_at!=0 &&
- last_fish_arrived_at+delay > now)) {
- debugBelch("--$$ <%llu> delaying FISH until %llu (last fish %llu, delay %llu)\n",
- now, last_fish_arrived_at+delay,
- last_fish_arrived_at,
- delay);
- });
-
- if (outstandingFishes < RtsFlags.ParFlags.maxFishes &&
- advisory_thread_count < RtsFlags.ParFlags.maxThreads) { // send a FISH, but when?
- if (last_fish_arrived_at==0 ||
- (last_fish_arrived_at+delay <= now)) { // send FISH now!
- /* outstandingFishes is set in sendFish, processFish;
- avoid flooding system with fishes via delay */
- next_fish_to_send_at = 0;
- } else {
- /* ToDo: this should be done in the main scheduling loop to avoid the
- busy wait here; not so bad if fish delay is very small */
- int iq = 0; // DEBUGGING -- HWL
- next_fish_to_send_at = last_fish_arrived_at+delay; // remember when to send
- /* send a fish when ready, but process messages that arrive in the meantime */
- do {
- if (PacketsWaiting()) {
- iq++; // DEBUGGING
- *receivedFinish = processMessages();
- }
- now = msTime();
- } while (!*receivedFinish || now<next_fish_to_send_at);
- // JB: This means the fish could become obsolete, if we receive
- // work. Better check for work again?
- // last line: while (!receivedFinish || !haveWork || now<...)
- // next line: if (receivedFinish || haveWork )
-
- if (*receivedFinish) // no need to send a FISH if we are finishing anyway
- return rtsFalse; // NB: this will leave scheduler loop
- // immediately after return!
-
- IF_PAR_DEBUG(fish, // verbose,
- debugBelch("--$$ <%llu> sent delayed fish (%d processMessages); active/total threads=%d/%d\n",now,iq,run_queue_len(),advisory_thread_count));
-
- }
-
- // JB: IMHO, this should all be hidden inside sendFish(...)
- /* pe = choosePE();
- sendFish(pe, thisPE, NEW_FISH_AGE, NEW_FISH_HISTORY,
- NEW_FISH_HUNGER);
-
- // Global statistics: count no. of fishes
- if (RtsFlags.ParFlags.ParStats.Global &&
- RtsFlags.GcFlags.giveStats > NO_GC_STATS) {
- globalParStats.tot_fish_mess++;
- }
- */
-
- /* delayed fishes must have been sent by now! */
- next_fish_to_send_at = 0;
- }
-
- *receivedFinish = processMessages();
-# endif /* SPARKS */
-
- return rtsFalse;
- /* NB: this function always returns rtsFalse, meaning the scheduler
- loop continues with the next iteration;
- rationale:
- return code means success in finding work; we enter this function
- if there is no local work, thus have to send a fish which takes
- time until it arrives with work; in the meantime we should process
- messages in the main loop;
- */
-}
-#endif // PARALLEL_HASKELL
-
-/* ----------------------------------------------------------------------------
- * PAR/GRAN: Report stats & debugging info(?)
- * ------------------------------------------------------------------------- */
-
-#if defined(PAR) || defined(GRAN)
+#if defined(THREADED_RTS)
static void
-scheduleGranParReport(void)
+scheduleActivateSpark(Capability *cap)
{
- ASSERT(run_queue_hd != END_TSO_QUEUE);
-
- /* Take a thread from the run queue, if we have work */
- POP_RUN_QUEUE(t); // take_off_run_queue(END_TSO_QUEUE);
-
- /* If this TSO has got its outport closed in the meantime,
- * it mustn't be run. Instead, we have to clean it up as if it was finished.
- * It has to be marked as TH_DEAD for this purpose.
- * If it is TH_TERM instead, it is supposed to have finished in the normal way.
-
-JB: TODO: investigate wether state change field could be nuked
- entirely and replaced by the normal tso state (whatnext
- field). All we want to do is to kill tsos from outside.
- */
-
- /* ToDo: write something to the log-file
- if (RTSflags.ParFlags.granSimStats && !sameThread)
- DumpGranEvent(GR_SCHEDULE, RunnableThreadsHd);
-
- CurrentTSO = t;
- */
- /* the spark pool for the current PE */
- pool = &(cap.r.rSparks); // cap = (old) MainCap
-
- IF_DEBUG(scheduler,
- debugBelch("--=^ %d threads, %d sparks on [%#x]\n",
- run_queue_len(), spark_queue_len(pool), CURRENT_PROC));
-
- IF_PAR_DEBUG(fish,
- debugBelch("--=^ %d threads, %d sparks on [%#x]\n",
- run_queue_len(), spark_queue_len(pool), CURRENT_PROC));
-
- if (RtsFlags.ParFlags.ParStats.Full &&
- (t->par.sparkname != (StgInt)0) && // only log spark generated threads
- (emitSchedule || // forced emit
- (t && LastTSO && t->id != LastTSO->id))) {
- /*
- we are running a different TSO, so write a schedule event to log file
- NB: If we use fair scheduling we also have to write a deschedule
- event for LastTSO; with unfair scheduling we know that the
- previous tso has blocked whenever we switch to another tso, so
- we don't need it in GUM for now
- */
- IF_PAR_DEBUG(fish, // schedule,
- debugBelch("____ scheduling spark generated thread %d (%lx) (%lx) via a forced emit\n",t->id,t,t->par.sparkname));
-
- DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
- GR_SCHEDULE, t, (StgClosure *)NULL, 0, 0);
- emitSchedule = rtsFalse;
+ if (anySparks())
+ {
+ createSparkThread(cap);
+ debugTrace(DEBUG_sched, "creating a spark thread");
}
-}
-#endif
+}
+#endif // PARALLEL_HASKELL || THREADED_RTS
/* ----------------------------------------------------------------------------
* After running a thread...
* ------------------------------------------------------------------------- */
static void
-schedulePostRunThread(void)
+schedulePostRunThread (Capability *cap, StgTSO *t)
{
-#if defined(PAR)
- /* HACK 675: if the last thread didn't yield, make sure to print a
- SCHEDULE event to the log file when StgRunning the next thread, even
- if it is the same one as before */
- LastTSO = t;
- TimeOfLastYield = CURRENT_TIME;
-#endif
+ // We have to be able to catch transactions that are in an
+ // infinite loop as a result of seeing an inconsistent view of
+ // memory, e.g.
+ //
+ // atomically $ do
+ // [a,b] <- mapM readTVar [ta,tb]
+ // when (a == b) loop
+ //
+ // and a is never equal to b given a consistent view of memory.
+ //
+ if (t -> trec != NO_TREC && t -> why_blocked == NotBlocked) {
+ if (!stmValidateNestOfTransactions (t -> trec)) {
+ debugTrace(DEBUG_sched | DEBUG_stm,
+ "trec %p found wasting its time", t);
+
+ // strip the stack back to the
+ // ATOMICALLY_FRAME, aborting the (nested)
+ // transaction, and saving the stack of any
+ // partially-evaluated thunks on the heap.
+ throwToSingleThreaded_(cap, t, NULL, rtsTrue);
+
+// ASSERT(get_itbl((StgClosure *)t->sp)->type == ATOMICALLY_FRAME);
+ }
+ }
/* some statistics gathering in the parallel case */
-
-#if defined(GRAN) || defined(PAR) || defined(EDEN)
- switch (ret) {
- case HeapOverflow:
-# if defined(GRAN)
- IF_DEBUG(gran, DumpGranEvent(GR_DESCHEDULE, t));
- globalGranStats.tot_heapover++;
-# elif defined(PAR)
- globalParStats.tot_heapover++;
-# endif
- break;
-
- case StackOverflow:
-# if defined(GRAN)
- IF_DEBUG(gran,
- DumpGranEvent(GR_DESCHEDULE, t));
- globalGranStats.tot_stackover++;
-# elif defined(PAR)
- // IF_DEBUG(par,
- // DumpGranEvent(GR_DESCHEDULE, t);
- globalParStats.tot_stackover++;
-# endif
- break;
-
- case ThreadYielding:
-# if defined(GRAN)
- IF_DEBUG(gran,
- DumpGranEvent(GR_DESCHEDULE, t));
- globalGranStats.tot_yields++;
-# elif defined(PAR)
- // IF_DEBUG(par,
- // DumpGranEvent(GR_DESCHEDULE, t);
- globalParStats.tot_yields++;
-# endif
- break;
-
- case ThreadBlocked:
-# if defined(GRAN)
- debugTrace(DEBUG_sched,
- "--<< thread %ld (%p; %s) stopped, blocking on node %p [PE %d] with BQ: ",
- t->id, t, whatNext_strs[t->what_next], t->block_info.closure,
- (t->block_info.closure==(StgClosure*)NULL ? 99 : where_is(t->block_info.closure)));
- if (t->block_info.closure!=(StgClosure*)NULL)
- print_bq(t->block_info.closure);
- debugBelch("\n"));
-
- // ??? needed; should emit block before
- IF_DEBUG(gran,
- DumpGranEvent(GR_DESCHEDULE, t));
- prune_eventq(t, (StgClosure *)NULL); // prune ContinueThreads for t
- /*
- ngoq Dogh!
- ASSERT(procStatus[CurrentProc]==Busy ||
- ((procStatus[CurrentProc]==Fetching) &&
- (t->block_info.closure!=(StgClosure*)NULL)));
- if (run_queue_hds[CurrentProc] == END_TSO_QUEUE &&
- !(!RtsFlags.GranFlags.DoAsyncFetch &&
- procStatus[CurrentProc]==Fetching))
- procStatus[CurrentProc] = Idle;
- */
-# elif defined(PAR)
-//++PAR++ blockThread() writes the event (change?)
-# endif
- break;
-
- case ThreadFinished:
- break;
-
- default:
- barf("parGlobalStats: unknown return code");
- break;
- }
-#endif
}
/* -----------------------------------------------------------------------------
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;
}
}
- debugTrace(DEBUG_sched,
- "--<< thread %ld (%s) stopped: HeapOverflow\n",
- (long)t->id, whatNext_strs[t->what_next]);
-
-#if defined(GRAN)
- ASSERT(!is_on_queue(t,CurrentProc));
-#elif defined(PARALLEL_HASKELL)
- /* Currently we emit a DESCHEDULE event before GC in GUM.
- ToDo: either add separate event to distinguish SYSTEM time from rest
- or just nuke this DESCHEDULE (and the following SCHEDULE) */
- if (0 && RtsFlags.ParFlags.ParStats.Full) {
- DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
- GR_DESCHEDULE, t, (StgClosure *)NULL, 0, 0);
- emitSchedule = rtsTrue;
+ 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);
+ } else {
+ pushOnRunQueue(cap,t);
}
-#endif
-
- pushOnRunQueue(cap,t);
return rtsTrue;
/* actual GC is done at the end of the while loop in schedule() */
}
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 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.
- context_switch = 0;
+ 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
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]);
+ (long)t->id, what_next_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);
+ 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
if (t->what_next != prev_what_next) {
return rtsTrue;
}
-
-#if defined(GRAN)
- ASSERT(!is_on_queue(t,CurrentProc));
-
- IF_DEBUG(sanity,
- //debugBelch("&& Doing sanity check on all ThreadQueues (and their TSOs).");
- checkThreadQsSanity(rtsTrue));
-
-#endif
addToRunQueue(cap,t);
-#if defined(GRAN)
- /* add a ContinueThread event to actually process the thread */
- new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
- ContinueThread,
- t, (StgClosure*)NULL, (rtsSpark*)NULL);
- IF_GRAN_DEBUG(bq,
- debugBelch("GRAN: eventq and runnableq after adding yielded thread to queue again:\n");
- G_EVENTQ(0);
- G_CURR_THREADQ(0));
-#endif
return rtsFalse;
}
static void
scheduleHandleThreadBlocked( StgTSO *t
-#if !defined(GRAN) && !defined(DEBUG)
+#if !defined(DEBUG)
STG_UNUSED
#endif
)
{
-#if defined(GRAN)
- IF_DEBUG(scheduler,
- debugBelch("--<< thread %ld (%p; %s) stopped, blocking on node %p [PE %d] with BQ: \n",
- t->id, t, whatNext_strs[t->what_next], t->block_info.closure, (t->block_info.closure==(StgClosure*)NULL ? 99 : where_is(t->block_info.closure)));
- if (t->block_info.closure!=(StgClosure*)NULL) print_bq(t->block_info.closure));
-
- // ??? needed; should emit block before
- IF_DEBUG(gran,
- DumpGranEvent(GR_DESCHEDULE, t));
- prune_eventq(t, (StgClosure *)NULL); // prune ContinueThreads for t
- /*
- ngoq Dogh!
- ASSERT(procStatus[CurrentProc]==Busy ||
- ((procStatus[CurrentProc]==Fetching) &&
- (t->block_info.closure!=(StgClosure*)NULL)));
- if (run_queue_hds[CurrentProc] == END_TSO_QUEUE &&
- !(!RtsFlags.GranFlags.DoAsyncFetch &&
- procStatus[CurrentProc]==Fetching))
- procStatus[CurrentProc] = Idle;
- */
-#elif defined(PAR)
- IF_DEBUG(scheduler,
- debugBelch("--<< thread %ld (%p; %s) stopped, blocking on node %p with BQ: \n",
- t->id, t, whatNext_strs[t->what_next], t->block_info.closure));
- IF_PAR_DEBUG(bq,
-
- if (t->block_info.closure!=(StgClosure*)NULL)
- print_bq(t->block_info.closure));
-
- /* Send a fetch (if BlockedOnGA) and dump event to log file */
- blockThread(t);
-
- /* whatever we schedule next, we must log that schedule */
- emitSchedule = rtsTrue;
-
-#else /* !GRAN */
// We don't need to do anything. The thread is blocked, and it
// has tidied up its stack and placed itself on whatever queue
// 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();
- }
-#endif
-
- /* Only for dumping event to log file
- ToDo: do I need this in GranSim, too?
- blockThread(t);
- */
+ 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]);
-
- /* Inform the Hpc that a thread has finished */
- hs_hpc_thread_finished_event(t);
-
-#if defined(GRAN)
- endThread(t, CurrentProc); // clean-up the thread
-#elif defined(PARALLEL_HASKELL)
- /* For now all are advisory -- HWL */
- //if(t->priority==AdvisoryPriority) ??
- advisory_thread_count--; // JB: Caution with this counter, buggy!
-
-# if defined(DIST)
- if(t->dist.priority==RevalPriority)
- FinishReval(t);
-# endif
-
-# if defined(EDENOLD)
- // the thread could still have an outport... (BUG)
- if (t->eden.outport != -1) {
- // delete the outport for the tso which has finished...
- IF_PAR_DEBUG(eden_ports,
- debugBelch("WARNING: Scheduler removes outport %d for TSO %d.\n",
- t->eden.outport, t->id));
- deleteOPT(t);
- }
- // thread still in the process (HEAVY BUG! since outport has just been closed...)
- if (t->eden.epid != -1) {
- IF_PAR_DEBUG(eden_ports,
- debugBelch("WARNING: Scheduler removes TSO %d from process %d .\n",
- t->id, t->eden.epid));
- removeTSOfromProcess(t);
- }
-# endif
-
-# if defined(PAR)
- if (RtsFlags.ParFlags.ParStats.Full &&
- !RtsFlags.ParFlags.ParStats.Suppressed)
- DumpEndEvent(CURRENT_PROC, t, rtsFalse /* not mandatory */);
- // t->par only contains statistics: left out for now...
- IF_PAR_DEBUG(fish,
- debugBelch("**** end thread: ended sparked thread %d (%lx); sparkname: %lx\n",
- t->id,t,t->par.sparkname));
-# endif
-#endif // PARALLEL_HASKELL
+ // blocked exceptions can now complete, even if the thread was in
+ // blocked mode (see #2910). This unconditionally calls
+ // lockTSO(), which ensures that we don't miss any threads that
+ // are engaged in throwTo() with this thread as a target.
+ awakenBlockedExceptionQueue (cap, t);
//
// Check whether the thread that just completed was a bound
// point where we can deal with this. Leaving it on the run
// queue also ensures that the garbage collector knows about
// this thread and its return value (it gets dropped from the
- // all_threads list so there's no other way to find it).
+ // step->threads list so there's no other way to find it).
appendToRunQueue(cap,t);
return rtsFalse;
#else
*(task->ret) = NULL;
}
if (sched_state >= SCHED_INTERRUPTING) {
- task->stat = Interrupted;
+ if (heap_overflow) {
+ task->stat = HeapExhausted;
+ } else {
+ task->stat = Interrupted;
+ }
} else {
task->stat = Killed;
}
}
/* -----------------------------------------------------------------------------
- * Perform a heap census, if PROFILING
+ * Perform a heap census
* -------------------------------------------------------------------------- */
static rtsBool
-scheduleDoHeapProfile( rtsBool ready_to_gc STG_UNUSED )
+scheduleNeedHeapProfile( rtsBool ready_to_gc STG_UNUSED )
{
-#if defined(PROFILING)
// When we have +RTS -i0 and we're heap profiling, do a census at
// every GC. This lets us get repeatable runs for debugging.
if (performHeapProfile ||
(RtsFlags.ProfFlags.profileInterval==0 &&
RtsFlags.ProfFlags.doHeapProfile && ready_to_gc)) {
-
- // checking black holes is necessary before GC, otherwise
- // there may be threads that are unreachable except by the
- // blackhole queue, which the GC will consider to be
- // deadlocked.
- scheduleCheckBlackHoles(&MainCapability);
-
- debugTrace(DEBUG_sched, "garbage collecting before heap census");
- GarbageCollect(rtsTrue);
-
- debugTrace(DEBUG_sched, "performing heap census");
- heapCensus();
-
- performHeapProfile = rtsFalse;
- return rtsTrue; // true <=> we already GC'd
+ return rtsTrue;
+ } else {
+ return rtsFalse;
}
-#endif
- return rtsFalse;
}
/* -----------------------------------------------------------------------------
static Capability *
scheduleDoGC (Capability *cap, Task *task USED_IF_THREADS, rtsBool force_major)
{
- StgTSO *t;
+ rtsBool heap_census;
#ifdef THREADED_RTS
- static volatile StgWord waiting_for_gc;
- rtsBool was_waiting;
+ /* extern static volatile StgWord waiting_for_gc;
+ lives inside capability.c */
+ 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->steps[0].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.
//
-
- was_waiting = cas(&waiting_for_gc, 0, 1);
- if (was_waiting) {
+
+ /* Other capabilities are prevented from running yet more Haskell
+ threads if waiting_for_gc is set. Tested inside
+ yieldCapability() and releaseCapability() in Capability.c */
+
+ 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
}
- 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;
- context_switch = 1;
- waitForReturnCapability(&pcap, task);
- if (pcap != &capabilities[i]) {
- barf("scheduleDoGC: got the wrong capability");
- }
- }
+ setContextSwitches();
+
+ // 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)
+ {
+ traceSchedEvent(cap, EVENT_REQUEST_SEQ_GC, 0, 0);
+ // 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.
+ traceSchedEvent(cap, EVENT_REQUEST_PAR_GC, 0, 0);
+ debugTrace(DEBUG_sched, "ready_to_gc, grabbing GC threads");
- waiting_for_gc = rtsFalse;
+ waitForGcThreads(cap);
+ }
#endif
- /* Kick any transactions which are invalid back to their
- * atomically frames. When next scheduled they will try to
- * commit, this commit will fail and they will retry.
- */
- {
- StgTSO *next;
-
- for (t = all_threads; t != END_TSO_QUEUE; t = next) {
- if (t->what_next == ThreadRelocated) {
- next = t->link;
- } else {
- next = t->global_link;
-
- // This is a good place to check for blocked
- // exceptions. It might be the case that a thread is
- // blocked on delivering an exception to a thread that
- // is also blocked - we try to ensure that this
- // doesn't happen in throwTo(), but it's too hard (or
- // impossible) to close all the race holes, so we
- // accept that some might get through and deal with
- // them here. A GC will always happen at some point,
- // even if the system is otherwise deadlocked.
- maybePerformBlockedException (&capabilities[0], t);
-
- if (t -> trec != NO_TREC && t -> why_blocked == NotBlocked) {
- if (!stmValidateNestOfTransactions (t -> trec)) {
- debugTrace(DEBUG_sched | DEBUG_stm,
- "trec %p found wasting its time", t);
-
- // strip the stack back to the
- // ATOMICALLY_FRAME, aborting the (nested)
- // transaction, and saving the stack of any
- // partially-evaluated thunks on the heap.
- throwToSingleThreaded_(&capabilities[0], t,
- NULL, rtsTrue, NULL);
-
-#ifdef REG_R1
- ASSERT(get_itbl((StgClosure *)t->sp)->type == ATOMICALLY_FRAME);
-#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.
- */
#if defined(THREADED_RTS)
- debugTrace(DEBUG_sched, "doing GC");
+ traceSchedEvent(cap, EVENT_GC_START, 0, 0);
+ // 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);
-
+ traceSchedEvent(cap, EVENT_GC_END, 0, 0);
+
+ 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)
- // 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_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
+ spark pools. No concurrent stealing or adding of new sparks can
+ occur. Should be defined in Sparks.c. */
+ balanceSparkPoolsCaps(n_capabilities, capabilities);
+#endif
+
+#if defined(THREADED_RTS)
+ 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;
}
#endif
-#if defined(GRAN)
- /* add a ContinueThread event to continue execution of current thread */
- new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
- ContinueThread,
- t, (StgClosure*)NULL, (rtsSpark*)NULL);
- IF_GRAN_DEBUG(bq,
- debugBelch("GRAN: eventq and runnableq after Garbage collection:\n\n");
- G_EVENTQ(0);
- G_CURR_THREADQ(0));
-#endif /* GRAN */
-
return cap;
}
* Singleton fork(). Do not copy any running threads.
* ------------------------------------------------------------------------- */
-StgInt
+pid_t
forkProcess(HsStablePtr *entry
#ifndef FORKPROCESS_PRIMOP_SUPPORTED
STG_UNUSED
pid_t pid;
StgTSO* t,*next;
Capability *cap;
+ nat s;
#if defined(THREADED_RTS)
if (RtsFlags.ParFlags.nNodes > 1) {
// ToDo: for SMP, we should probably acquire *all* the capabilities
cap = rts_lock();
+ // no funny business: hold locks while we fork, otherwise if some
+ // other thread is holding a lock when the fork happens, the data
+ // structure protected by the lock will forever be in an
+ // inconsistent state in the child. See also #1391.
+ ACQUIRE_LOCK(&sched_mutex);
+ ACQUIRE_LOCK(&cap->lock);
+ ACQUIRE_LOCK(&cap->running_task->lock);
+
pid = fork();
if (pid) { // parent
+ RELEASE_LOCK(&sched_mutex);
+ RELEASE_LOCK(&cap->lock);
+ RELEASE_LOCK(&cap->running_task->lock);
+
// just return the pid
rts_unlock(cap);
return pid;
} else { // child
+#if defined(THREADED_RTS)
+ initMutex(&sched_mutex);
+ initMutex(&cap->lock);
+ initMutex(&cap->running_task->lock);
+#endif
+
// Now, all OS threads except the thread that forked are
// stopped. We need to stop all Haskell threads, including
// those involved in foreign calls. Also we need to delete
// all Tasks, because they correspond to OS threads that are
// now gone.
- for (t = all_threads; t != END_TSO_QUEUE; t = next) {
+ 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;
+ next = t->_link;
} else {
next = t->global_link;
// don't allow threads to catch the ThreadKilled
// threads may be evaluating thunks that we need later.
deleteThread_(cap,t);
}
+ }
}
// Empty the run queue. It seems tempting to let all the
// don't exist now:
cap->suspended_ccalling_tasks = NULL;
- // Empty the all_threads list. Otherwise, the garbage
+ // Empty the threads lists. Otherwise, the garbage
// collector may attempt to resurrect some of these threads.
- all_threads = END_TSO_QUEUE;
+ for (s = 0; s < total_steps; s++) {
+ all_steps[s].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);
}
}
cap->returning_tasks_tl = NULL;
#endif
+ // On Unix, all timers are reset in the child, so we need to start
+ // the timer again.
+ initTimer();
+ startTimer();
+
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;
+
debugTrace(DEBUG_sched,"deleting all threads");
- for (t = all_threads; t != END_TSO_QUEUE; t = next) {
+ 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;
+ next = t->_link;
} else {
next = t->global_link;
deleteThread(cap,t);
}
+ }
}
// The run queue now contains a bunch of ThreadKilled threads. We
task = cap->running_task;
tso = cap->r.rCurrentTSO;
- debugTrace(DEBUG_sched,
- "thread %lu did a safe foreign call",
- (unsigned long)cap->r.rCurrentTSO->id);
+ traceSchedEvent(cap, EVENT_STOP_THREAD, tso, THREAD_SUSPENDED_FOREIGN_CALL);
// XXX this might not be necessary --SDM
tso->what_next = ThreadRunGHC;
suspendTask(cap,task);
cap->in_haskell = rtsFalse;
- releaseCapability_(cap);
+ releaseCapability_(cap,rtsFalse);
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);
tso = task->suspended_tso;
task->suspended_tso = NULL;
- tso->link = END_TSO_QUEUE;
- debugTrace(DEBUG_sched, "thread %lu: re-entering RTS", (unsigned long)tso->id);
+ tso->_link = END_TSO_QUEUE; // no write barrier reqd
+
+ traceSchedEvent(cap, EVENT_RUN_THREAD, tso, tso->what_next);
if (tso->why_blocked == BlockedOnCCall) {
- awakenBlockedExceptionQueue(cap,tso);
+ // avoid locking the TSO if we don't have to
+ if (tso->blocked_exceptions != END_TSO_QUEUE) {
+ awakenBlockedExceptionQueue(cap,tso);
+ }
tso->flags &= ~(TSO_BLOCKEX | TSO_INTERRUPTIBLE);
}
#endif
/* We might have GC'd, mark the TSO dirty again */
- dirtyTSO(tso);
+ dirty_TSO(cap,tso);
IF_DEBUG(sanity, checkTSO(tso));
if (cpu == cap->no) {
appendToRunQueue(cap,tso);
} else {
- migrateThreadToCapability_lock(&capabilities[cpu],tso);
+ traceSchedEvent (cap, EVENT_MIGRATE_THREAD, tso, capabilities[cpu].no);
+ wakeupThreadOnCapability(cap, &capabilities[cpu], tso);
}
#else
appendToRunQueue(cap,tso);
debugTrace(DEBUG_sched, "new bound thread (%lu)", (unsigned long)tso->id);
-#if defined(GRAN)
- /* GranSim specific init */
- CurrentTSO = m->tso; // the TSO to run
- procStatus[MainProc] = Busy; // status of main PE
- CurrentProc = MainProc; // PE to run it on
-#endif
-
cap = schedule(cap,task);
ASSERT(task->stat != NoStatus);
* ------------------------------------------------------------------------- */
#if defined(THREADED_RTS)
-void
+void OSThreadProcAttr
workerStart(Task *task)
{
Capability *cap;
cap = task->cap;
RELEASE_LOCK(&task->lock);
+ if (RtsFlags.ParFlags.setAffinity) {
+ setThreadAffinity(cap->no, n_capabilities);
+ }
+
// 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
void
initScheduler(void)
{
-#if defined(GRAN)
- nat i;
- for (i=0; i<=MAX_PROC; i++) {
- run_queue_hds[i] = END_TSO_QUEUE;
- run_queue_tls[i] = END_TSO_QUEUE;
- blocked_queue_hds[i] = END_TSO_QUEUE;
- blocked_queue_tls[i] = END_TSO_QUEUE;
- ccalling_threadss[i] = END_TSO_QUEUE;
- blackhole_queue[i] = END_TSO_QUEUE;
- sleeping_queue = END_TSO_QUEUE;
- }
-#elif !defined(THREADED_RTS)
+#if !defined(THREADED_RTS)
blocked_queue_hd = END_TSO_QUEUE;
blocked_queue_tl = END_TSO_QUEUE;
sleeping_queue = END_TSO_QUEUE;
#endif
blackhole_queue = END_TSO_QUEUE;
- all_threads = END_TSO_QUEUE;
- context_switch = 0;
sched_state = SCHED_RUNNING;
+ recent_activity = ACTIVITY_YES;
#if defined(THREADED_RTS)
/* Initialise the mutex and condition variables used by
initTaskManager();
-#if defined(THREADED_RTS) || defined(PARALLEL_HASKELL)
+#if defined(THREADED_RTS)
initSparkPools();
#endif
}
#endif
- trace(TRACE_sched, "start: %d capabilities", n_capabilities);
-
RELEASE_LOCK(&sched_mutex);
}
void
-exitScheduler( void )
+exitScheduler(
+ rtsBool wait_foreign
+#if !defined(THREADED_RTS)
+ __attribute__((unused))
+#endif
+)
+ /* 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);
+ releaseCapability(task->cap);
}
sched_state = SCHED_SHUTTING_DOWN;
nat i;
for (i = 0; i < n_capabilities; i++) {
- shutdownCapability(&capabilities[i], task);
+ shutdownCapability(&capabilities[i], task, wait_foreign);
}
boundTaskExiting(task);
- stopTaskManager();
}
-#else
- freeCapability(&MainCapability);
#endif
}
void
freeScheduler( void )
{
- freeTaskManager();
- if (n_capabilities != 1) {
- stgFree(capabilities);
- }
-#if defined(THREADED_RTS)
- closeMutex(&sched_mutex);
-#endif
-}
-
-/* ---------------------------------------------------------------------------
- Where are the roots that we know about?
-
- - all the threads on the runnable queue
- - all the threads on the blocked queue
- - all the threads on the sleeping queue
- - all the thread currently executing a _ccall_GC
- - all the "main threads"
-
- ------------------------------------------------------------------------ */
+ nat still_running;
-/* This has to be protected either by the scheduler monitor, or by the
- garbage collection monitor (probably the latter).
- KH @ 25/10/99
-*/
-
-void
-GetRoots( evac_fn evac )
-{
- nat i;
- Capability *cap;
- Task *task;
-
-#if defined(GRAN)
- for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
- if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
- evac((StgClosure **)&run_queue_hds[i]);
- if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
- evac((StgClosure **)&run_queue_tls[i]);
-
- if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
- evac((StgClosure **)&blocked_queue_hds[i]);
- if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
- evac((StgClosure **)&blocked_queue_tls[i]);
- if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
- evac((StgClosure **)&ccalling_threads[i]);
+ 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);
+ }
}
-
- markEventQueue();
-
-#else /* !GRAN */
-
- for (i = 0; i < n_capabilities; i++) {
- cap = &capabilities[i];
- evac((StgClosure **)(void *)&cap->run_queue_hd);
- evac((StgClosure **)(void *)&cap->run_queue_tl);
+ RELEASE_LOCK(&sched_mutex);
#if defined(THREADED_RTS)
- evac((StgClosure **)(void *)&cap->wakeup_queue_hd);
- evac((StgClosure **)(void *)&cap->wakeup_queue_tl);
-#endif
- for (task = cap->suspended_ccalling_tasks; task != NULL;
- task=task->next) {
- debugTrace(DEBUG_sched,
- "evac'ing suspended TSO %lu", (unsigned long)task->suspended_tso->id);
- evac((StgClosure **)(void *)&task->suspended_tso);
- }
-
- }
-
-
-#if !defined(THREADED_RTS)
- evac((StgClosure **)(void *)&blocked_queue_hd);
- evac((StgClosure **)(void *)&blocked_queue_tl);
- evac((StgClosure **)(void *)&sleeping_queue);
-#endif
-#endif
-
- // evac((StgClosure **)&blackhole_queue);
-
-#if defined(THREADED_RTS) || defined(PARALLEL_HASKELL) || defined(GRAN)
- markSparkQueue(evac);
-#endif
-
-#if defined(RTS_USER_SIGNALS)
- // mark the signal handlers (signals should be already blocked)
- markSignalHandlers(evac);
+ 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);
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);
}
// while we are moving the TSO:
lockClosure((StgClosure *)tso);
- if (tso->stack_size >= tso->max_stack_size) {
+ 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.
debugTrace(DEBUG_gc,
"threadStackOverflow of TSO %ld (%p): stack too large (now %ld; max is %ld)",
}
/* Try to double the current stack size. If that takes us over the
- * maximum stack size for this thread, then use the maximum instead.
- * Finally round up so the TSO ends up as a whole number of blocks.
+ * 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
+ * can't raise the StackOverflow exception (see above), in which
+ * case just double the size). Finally round up so the TSO ends up as
+ * a whole number of blocks.
*/
- new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
+ if (tso->stack_size >= tso->max_stack_size) {
+ new_stack_size = tso->stack_size * 2;
+ } else {
+ new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
+ }
new_tso_size = (lnat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
TSO_STRUCT_SIZE)/sizeof(W_);
new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
"increasing stack size from %ld words to %d.",
(long)tso->stack_size, new_stack_size);
- dest = (StgTSO *)allocate(new_tso_size);
+ dest = (StgTSO *)allocateLocal(cap,new_tso_size);
TICK_ALLOC_TSO(new_stack_size,0);
/* copy the TSO block and the old stack into the new area */
* dead TSO's stack.
*/
tso->what_next = ThreadRelocated;
- tso->link = dest;
+ setTSOLink(cap,tso,dest);
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);
return dest;
}
+static StgTSO *
+threadStackUnderflow (Task *task STG_UNUSED, StgTSO *tso)
+{
+ bdescr *bd, *new_bd;
+ lnat free_w, tso_size_w;
+ StgTSO *new_tso;
+
+ tso_size_w = tso_sizeW(tso);
+
+ 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);
+
+ bd = Bdescr((StgPtr)tso);
+ new_bd = splitLargeBlock(bd, free_w / BLOCK_SIZE_W);
+ bd->free = bd->start + TSO_STRUCT_SIZEW;
+
+ new_tso = (StgTSO *)new_bd->start;
+ memcpy(new_tso,tso,TSO_STRUCT_SIZE);
+ new_tso->stack_size = new_bd->free - new_tso->stack;
+
+ 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
+
+ // The TSO attached to this Task may have moved, so update the
+ // pointer to it.
+ if (task->tso == tso) {
+ task->tso = new_tso;
+ }
+
+ unlockTSO(new_tso);
+ unlockTSO(tso);
+
+ IF_DEBUG(sanity,checkTSO(new_tso));
+
+ return new_tso;
+}
+
/* ---------------------------------------------------------------------------
Interrupt execution
- usually called inside a signal handler so it mustn't do anything fancy.
interruptStgRts(void)
{
sched_state = SCHED_INTERRUPTING;
- context_switch = 1;
+ 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
}
+#endif
/* -----------------------------------------------------------------------------
* checkBlackHoles()
prev = &blackhole_queue;
t = blackhole_queue;
while (t != END_TSO_QUEUE) {
+ if (t->what_next == ThreadRelocated) {
+ t = t->_link;
+ continue;
+ }
ASSERT(t->why_blocked == BlockedOnBlackHole);
- type = get_itbl(t->block_info.closure)->type;
+ 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);
- // urk, the threads migrate to the current capability
- // here, but we'd like to keep them on the original one.
*prev = t;
any_woke_up = rtsTrue;
} else {
- prev = &t->link;
- t = t->link;
+ prev = &t->_link;
+ t = t->_link;
}
}
return CATCH_RETRY_FRAME;
case CATCH_STM_FRAME: {
+ StgTRecHeader *trec = tso -> trec;
+ StgTRecHeader *outer = trec -> enclosing_trec;
debugTrace(DEBUG_stm,
"found CATCH_STM_FRAME at %p during retry", p);
- StgTRecHeader *trec = tso -> trec;
- StgTRecHeader *outer = stmGetEnclosingTRec(trec);
debugTrace(DEBUG_stm, "trec=%p outer=%p", trec, outer);
stmAbortTransaction(tso -> cap, trec);
stmFreeAbortedTRec(tso -> cap, trec);
{
StgTSO *tso, *next;
Capability *cap;
+ step *step;
for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
next = tso->global_link;
- tso->global_link = all_threads;
- all_threads = tso;
+
+ step = Bdescr((P_)tso)->step;
+ tso->global_link = step->threads;
+ step->threads = tso;
+
debugTrace(DEBUG_sched, "resurrecting thread %lu", (unsigned long)tso->id);
// Wake up the thread on the Capability it was last on
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,
- (StgClosure *)NonTermination_closure);
+ (StgClosure *)nonTermination_closure);
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 BlockedOnException:
+ // throwTo should never block indefinitely: if the target
+ // thread dies or completes, throwTo returns.
+ barf("resurrectThreads: thread BlockedOnException");
+ break;
default:
barf("resurrectThreads: thread blocked in a strange way");
}
}
}
+
+/* -----------------------------------------------------------------------------
+ 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;
+ Task *task, *saved_task;;
+ step *step;
+
+ task = myTask();
+ cap = task->cap;
+
+ 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);
+
+ // We must pretend this Capability belongs to the current Task
+ // for the time being, as invariants will be broken otherwise.
+ // In fact the current Task has exclusive access to the systme
+ // at this point, so this is just bookkeeping:
+ task->cap = tso->cap;
+ saved_task = tso->cap->running_task;
+ tso->cap->running_task = task;
+ maybePerformBlockedException(tso->cap, tso);
+ tso->cap->running_task = saved_task;
+ }
+
+ // Restore our original Capability:
+ task->cap = cap;
+}
projects / ghc-hetmet.git / blobdiff