*/
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;
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
}
/*
#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
+#ifdef RTS_SUPPORTS_THREADS
+ IF_DEBUG(scheduler,
+ fprintf(stderr,"worker thread (%p): released capability\n",
+ osThreadId()));
+#endif
return;
}
grabReturnCapability(Mutex* pMutex, Capability** pCap)
{
IF_DEBUG(scheduler,
- fprintf(stderr,"worker (%ld): returning, waiting for lock.\n", osThreadId()));
+ 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));
if ( noCapabilities() ) {
rts_n_waiting_workers++;
-------------------------------------------------------------------------- */
/*
- * 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()));
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()));
/*
- * 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)