#include "OSThreads.h"
#include "Capability.h"
#include "Schedule.h" /* to get at EMPTY_RUN_QUEUE() */
+#include "Signals.h" /* to get at handleSignalsInThisThread() */
#if !defined(SMP)
Capability MainCapability; /* for non-SMP, we have one global capability */
#endif
-static nat rts_n_free_capabilities;
+nat rts_n_free_capabilities;
#if defined(RTS_SUPPORTS_THREADS)
/* returning_worker_cond: when a worker thread returns from executing an
* there are one or more worker threads blocked waiting on
* returning_worker_cond.
*/
-static nat rts_n_waiting_workers = 0;
+nat rts_n_waiting_workers = 0;
/* thread_ready_cond: when signalled, a thread has become runnable for a
* task to execute.
* exclusive access to the RTS and all its data structures (that are not
* locked by the Scheduler's mutex).
*
- * thread_ready_cond is signalled whenever COND_NO_THREADS_READY doesn't hold.
+ * thread_ready_cond is signalled whenever noCapabilities doesn't hold.
*
*/
Condition thread_ready_cond = INIT_COND_VAR;
-#if 0
-/* For documentation purposes only */
-#define COND_NO_THREADS_READY() (noCapabilities() || EMPTY_RUN_QUEUE())
-#endif
/*
* To be able to make an informed decision about whether or not
void
initCapability( Capability *cap )
{
- cap->f.stgChk0 = (F_)__stg_chk_0;
- cap->f.stgChk1 = (F_)__stg_chk_1;
cap->f.stgGCEnter1 = (F_)__stg_gc_enter_1;
- cap->f.stgUpdatePAP = (F_)__stg_update_PAP;
+ cap->f.stgGCFun = (F_)__stg_gc_fun;
}
#if defined(SMP)
#if defined(SMP)
/* Free capability list. */
static Capability *free_capabilities; /* Available capabilities for running threads */
+static Capability *returning_capabilities;
+ /* Capabilities being passed to returning worker threads */
#endif
/* -----------------------------------------------------------------------------
*/
void grabCapability(Capability** cap)
{
+#ifdef RTS_SUPPORTS_THREADS
+ ASSERT(rts_n_free_capabilities > 0);
+#endif
#if !defined(SMP)
rts_n_free_capabilities = 0;
*cap = &MainCapability;
+ handleSignalsInThisThread();
#else
*cap = free_capabilities;
free_capabilities = (*cap)->link;
rts_n_free_capabilities--;
#endif
+#ifdef RTS_SUPPORTS_THREADS
+ IF_DEBUG(scheduler,
+ fprintf(stderr,"worker thread (%p): got capability\n",
+ osThreadId()));
+#endif
}
/*
STG_UNUSED
#endif
)
-{
-#if defined(SMP)
- cap->link = free_capabilities;
- free_capabilities = cap;
- rts_n_free_capabilities++;
-#else
- rts_n_free_capabilities = 1;
-#endif
-
+{ // Precondition: sched_mutex must be held
#if defined(RTS_SUPPORTS_THREADS)
+#ifndef SMP
+ ASSERT(rts_n_free_capabilities == 0);
+#endif
/* Check to see whether a worker thread can be given
the go-ahead to return the result of an external call..*/
if (rts_n_waiting_workers > 0) {
* thread that is yielding its capability will repeatedly
* signal returning_worker_cond.
*/
+#if defined(SMP)
+ // SMP variant untested
+ cap->link = returning_capabilities;
+ returning_capabilities = cap;
+#else
+#endif
rts_n_waiting_workers--;
signalCondition(&returning_worker_cond);
- } else if ( !EMPTY_RUN_QUEUE() ) {
- /* Signal that work is available */
+ } else /*if ( !EMPTY_RUN_QUEUE() )*/ {
+#if defined(SMP)
+ cap->link = free_capabilities;
+ free_capabilities = cap;
+ rts_n_free_capabilities++;
+#else
+ rts_n_free_capabilities = 1;
+#endif
+ /* Signal that a capability is available */
signalCondition(&thread_ready_cond);
+ startSchedulerTaskIfNecessary(); // if there is more work to be done,
+ // we'll need a new thread
}
#endif
- return;
+#ifdef RTS_SUPPORTS_THREADS
+ IF_DEBUG(scheduler,
+ fprintf(stderr,"worker thread (%p): released capability\n",
+ osThreadId()));
+#endif
+ return;
}
#if defined(RTS_SUPPORTS_THREADS)
grabReturnCapability(Mutex* pMutex, Capability** pCap)
{
IF_DEBUG(scheduler,
- fprintf(stderr,"worker (%ld): returning, waiting for lock.\n", osThreadId()));
- rts_n_waiting_workers++;
+ fprintf(stderr,"worker (%p): returning, waiting for lock.\n", osThreadId()));
IF_DEBUG(scheduler,
- fprintf(stderr,"worker (%ld): returning; workers waiting: %d\n",
+ fprintf(stderr,"worker (%p): returning; workers waiting: %d\n",
osThreadId(), rts_n_waiting_workers));
- while ( noCapabilities() ) {
+ if ( noCapabilities() ) {
+ rts_n_waiting_workers++;
+ wakeBlockedWorkerThread();
+ context_switch = 1; // make sure it's our turn soon
waitCondition(&returning_worker_cond, pMutex);
+#if defined(SMP)
+ *pCap = returning_capabilities;
+ returning_capabilities = (*pCap)->link;
+#else
+ *pCap = &MainCapability;
+ ASSERT(rts_n_free_capabilities == 0);
+ handleSignalsInThisThread();
+#endif
+ } else {
+ grabCapability(pCap);
}
-
- grabCapability(pCap);
return;
}
-------------------------------------------------------------------------- */
/*
- * Function: yieldToReturningWorker(Mutex*,Capability*)
+ * Function: yieldToReturningWorker(Mutex*,Capability*,Condition*)
*
* Purpose: when, upon entry to the Scheduler, an OS worker thread
* spots that one or more threads are blocked waiting for
* permission to return back their result, it gives up
- * its Capability.
+ * its Capability.
+ * Immediately afterwards, it tries to reaquire the Capabilty
+ * using waitForWorkCapability.
+ *
*
* Pre-condition: pMutex is assumed held and the thread possesses
* a Capability.
- * Post-condition: pMutex isn't held and the Capability has
- * been given back.
+ * Post-condition: pMutex is held and the thread possesses
+ * a Capability.
*/
void
-yieldToReturningWorker(Mutex* pMutex, Capability** pCap)
+yieldToReturningWorker(Mutex* pMutex, Capability** pCap, Condition* pThreadCond)
{
- if ( rts_n_waiting_workers > 0 && noCapabilities() ) {
+ if ( rts_n_waiting_workers > 0 ) {
IF_DEBUG(scheduler,
- fprintf(stderr,"worker thread (%ld): giving up RTS token\n", osThreadId()));
+ fprintf(stderr,"worker thread (%p): giving up RTS token\n", osThreadId()));
releaseCapability(*pCap);
- /* And wait for work */
- waitForWorkCapability(pMutex, pCap, rtsFalse);
+ /* And wait for work */
+ waitForWorkCapability(pMutex, pCap, pThreadCond);
+ IF_DEBUG(scheduler,
+ fprintf(stderr,"worker thread (%p): got back RTS token (after yieldToReturningWorker)\n",
+ osThreadId()));
}
return;
}
/*
- * Function: waitForWorkCapability(Mutex*, Capability**, rtsBool)
+ * Function: waitForWorkCapability(Mutex*, Capability**, Condition*)
*
* Purpose: wait for a Capability to become available. In
* the process of doing so, updates the number
* work. That counter is used when deciding whether or
* not to create a new worker thread when an external
* call is made.
+ * If pThreadCond is not NULL, a capability can be specifically
+ * passed to this thread using passCapability.
*
* Pre-condition: pMutex is held.
+ * Post-condition: pMutex is held and *pCap is held by the current thread
*/
+
+static Condition *passTarget = NULL;
+static rtsBool passingCapability = rtsFalse;
+
void
-waitForWorkCapability(Mutex* pMutex, Capability** pCap, rtsBool runnable)
+waitForWorkCapability(Mutex* pMutex, Capability** pCap, Condition* pThreadCond)
{
- while ( noCapabilities() || (runnable && EMPTY_RUN_QUEUE()) ) {
- rts_n_waiting_tasks++;
- waitCondition(&thread_ready_cond, pMutex);
- rts_n_waiting_tasks--;
+#ifdef SMP
+ #error SMP version not implemented
+#endif
+ IF_DEBUG(scheduler,
+ fprintf(stderr,"worker thread (%p): wait for cap (cond: %p)\n",
+ osThreadId(),pThreadCond));
+ while ( noCapabilities() || (passingCapability && passTarget != pThreadCond)) {
+ if(pThreadCond)
+ {
+ waitCondition(pThreadCond, pMutex);
+ IF_DEBUG(scheduler,
+ fprintf(stderr,"worker thread (%p): get passed capability\n",
+ osThreadId()));
+ }
+ else
+ {
+ rts_n_waiting_tasks++;
+ waitCondition(&thread_ready_cond, pMutex);
+ rts_n_waiting_tasks--;
+ IF_DEBUG(scheduler,
+ fprintf(stderr,"worker thread (%p): get normal capability\n",
+ osThreadId()));
+ }
}
+ passingCapability = rtsFalse;
grabCapability(pCap);
return;
}
+
+/*
+ * Function: passCapability(Mutex*, Capability*, Condition*)
+ *
+ * Purpose: Let go of the capability and make sure the thread associated
+ * with the Condition pTargetThreadCond gets it next.
+ *
+ * Pre-condition: pMutex is held and cap is held by the current thread
+ * Post-condition: pMutex is held; cap will be grabbed by the "target"
+ * thread when pMutex is released.
+ */
+
+void
+passCapability(Mutex* pMutex, Capability* cap, Condition *pTargetThreadCond)
+{
+#ifdef SMP
+ #error SMP version not implemented
+#endif
+ rts_n_free_capabilities = 1;
+ signalCondition(pTargetThreadCond);
+ passTarget = pTargetThreadCond;
+ passingCapability = rtsTrue;
+ IF_DEBUG(scheduler,
+ fprintf(stderr,"worker thread (%p): passCapability\n",
+ osThreadId()));
+}
+
+/*
+ * Function: passCapabilityToWorker(Mutex*, Capability*)
+ *
+ * Purpose: Let go of the capability and make sure that a
+ * "plain" worker thread (not a bound thread) gets it next.
+ *
+ * Pre-condition: pMutex is held and cap is held by the current thread
+ * Post-condition: pMutex is held; cap will be grabbed by the "target"
+ * thread when pMutex is released.
+ */
+
+void
+passCapabilityToWorker(Mutex* pMutex, Capability* cap)
+{
+#ifdef SMP
+ #error SMP version not implemented
+#endif
+ rts_n_free_capabilities = 1;
+ signalCondition(&thread_ready_cond);
+ startSchedulerTaskIfNecessary();
+ passTarget = NULL;
+ passingCapability = rtsTrue;
+ IF_DEBUG(scheduler,
+ fprintf(stderr,"worker thread (%p): passCapabilityToWorker\n",
+ osThreadId()));
+}
+
+
+
#endif /* RTS_SUPPORTS_THREADS */
#if defined(SMP)
}
free_capabilities = cap;
rts_n_free_capabilities = n;
+ returning_capabilities = NULL;
IF_DEBUG(scheduler,fprintf(stderr,"scheduler: Allocated %d capabilities\n", n_free_capabilities););
}
#endif /* SMP */
projects / ghc-hetmet.git / blobdiff