* Task.startTask() uses its current value.
*/
nat rts_n_waiting_tasks = 0;
+
+static Condition *passTarget = NULL;
+static rtsBool passingCapability = rtsFalse;
#endif
/* -----------------------------------------------------------------------------
*/
void grabCapability(Capability** cap)
{
-#ifdef RTS_SUPPORTS_THREADS
- ASSERT(rts_n_free_capabilities > 0);
-#endif
#if !defined(SMP)
+ ASSERT(rts_n_free_capabilities == 1);
rts_n_free_capabilities = 0;
*cap = &MainCapability;
handleSignalsInThisThread();
free_capabilities = (*cap)->link;
rts_n_free_capabilities--;
#endif
+#ifdef RTS_SUPPORTS_THREADS
+ IF_DEBUG(scheduler, sched_belch("worker: got capability"));
+#endif
}
/*
#endif
rts_n_waiting_workers--;
signalCondition(&returning_worker_cond);
+ IF_DEBUG(scheduler, sched_belch("worker: released capability to returning worker"));
} else /*if ( !EMPTY_RUN_QUEUE() )*/ {
#if defined(SMP)
cap->link = free_capabilities;
#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
+ IF_DEBUG(scheduler, sched_belch("worker: released capability"));
}
#endif
- return;
+ return;
}
#if defined(RTS_SUPPORTS_THREADS)
void
grabReturnCapability(Mutex* pMutex, Capability** pCap)
{
- IF_DEBUG(scheduler,
- fprintf(stderr,"worker (%ld): returning, waiting for lock.\n", osThreadId()));
- IF_DEBUG(scheduler,
- fprintf(stderr,"worker (%ld): returning; workers waiting: %d\n",
- osThreadId(), rts_n_waiting_workers));
- if ( noCapabilities() ) {
+ IF_DEBUG(scheduler,
+ sched_belch("worker: returning; workers waiting: %d",
+ rts_n_waiting_workers));
+ if ( noCapabilities() || passingCapability ) {
rts_n_waiting_workers++;
wakeBlockedWorkerThread();
context_switch = 1; // make sure it's our turn soon
-------------------------------------------------------------------------- */
/*
- * 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 is 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 ) {
- IF_DEBUG(scheduler,
- fprintf(stderr,"worker thread (%p): giving up RTS token\n", osThreadId()));
+ IF_DEBUG(scheduler, sched_belch("worker: giving up capability"));
releaseCapability(*pCap);
/* And wait for work */
- waitForWorkCapability(pMutex, pCap, rtsFalse);
+ waitForWorkCapability(pMutex, pCap, pThreadCond);
IF_DEBUG(scheduler,
- fprintf(stderr,"worker thread (%p): got back RTS token (after yieldToReturningWorker)\n",
- osThreadId()));
+ sched_belch("worker: got back capability (after yieldToReturningWorker)"));
}
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
*/
+
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
+ while ( noCapabilities() || (passingCapability && passTarget != pThreadCond)) {
+ IF_DEBUG(scheduler,
+ sched_belch("worker: wait for capability (cond: %p)",
+ pThreadCond));
+ if(pThreadCond)
+ {
+ waitCondition(pThreadCond, pMutex);
+ IF_DEBUG(scheduler, sched_belch("worker: get passed capability"));
+ }
+ else
+ {
+ rts_n_waiting_tasks++;
+ waitCondition(&thread_ready_cond, pMutex);
+ rts_n_waiting_tasks--;
+ IF_DEBUG(scheduler, sched_belch("worker: get normal capability"));
+ }
}
+ 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, sched_belch("worker: passCapability"));
+}
+
+/*
+ * 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, sched_belch("worker: passCapabilityToWorker"));
+}
+
+
+
#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););
+ IF_DEBUG(scheduler,
+ sched_belch("allocated %d capabilities", n_free_capabilities));
}
#endif /* SMP */
projects / ghc-hetmet.git / blobdiff