* Task.startTask() uses its current value.
*/
nat rts_n_waiting_tasks = 0;
-
-static Condition *passTarget = NULL;
-static rtsBool passingCapability = rtsFalse;
#endif
#if defined(SMP)
#define UNUSED_IF_NOT_SMP STG_UNUSED
#endif
+
+#if defined(RTS_SUPPORTS_THREADS)
+INLINE_HEADER rtsBool
+ANY_WORK_FOR_ME( Condition *cond )
+{
+ // If the run queue is not empty, then we only wake up the guy who
+ // can run the thread at the head, even if there is some other
+ // reason for this task to run (eg. interrupted=rtsTrue).
+ if (!EMPTY_RUN_QUEUE()) {
+ if (run_queue_hd->main == NULL) {
+ return (cond == NULL);
+ } else {
+ return (&run_queue_hd->main->bound_thread_cond == cond);
+ }
+ }
+
+ return blackholes_need_checking
+ || interrupted
#if defined(RTS_USER_SIGNALS)
-#define ANY_WORK_TO_DO() (!EMPTY_RUN_QUEUE() || interrupted || blackholes_need_checking || signals_pending())
-#else
-#define ANY_WORK_TO_DO() (!EMPTY_RUN_QUEUE() || interrupted || blackholes_need_checking)
+ || signals_pending()
+#endif
+ ;
+}
#endif
+INLINE_HEADER rtsBool
+ANY_WORK_TO_DO(void)
+{
+ return (!EMPTY_RUN_QUEUE()
+ || interrupted
+ || blackholes_need_checking
+#if defined(RTS_USER_SIGNALS)
+ || signals_pending()
+#endif
+ );
+}
+
/* ----------------------------------------------------------------------------
Initialisation
------------------------------------------------------------------------- */
// Decrement the counter here to avoid livelock where the
// thread that is yielding its capability will repeatedly
// signal returning_worker_cond.
-
rts_n_waiting_workers--;
signalCondition(&returning_worker_cond);
- IF_DEBUG(scheduler, sched_belch("worker: released capability to returning worker"));
- } else if (passingCapability) {
- if (passTarget == NULL) {
- signalCondition(&thread_ready_cond);
- startSchedulerTaskIfNecessary();
- } else {
- signalCondition(passTarget);
- }
- rts_n_free_capabilities++;
- IF_DEBUG(scheduler, sched_belch("worker: released capability, passing it"));
-
+ IF_DEBUG(scheduler,
+ sched_belch("worker: released capability to returning worker"));
} else {
rts_n_free_capabilities++;
- // Signal that a capability is available
- if (rts_n_waiting_tasks > 0 && ANY_WORK_TO_DO()) {
- signalCondition(&thread_ready_cond);
- }
- startSchedulerTaskIfNecessary();
IF_DEBUG(scheduler, sched_belch("worker: released capability"));
+ threadRunnable();
}
#endif
return;
sched_belch("worker: returning; workers waiting: %d",
rts_n_waiting_workers));
- if ( noCapabilities() || passingCapability ) {
+ if ( noCapabilities() ) {
rts_n_waiting_workers++;
context_switch = 1; // make sure it's our turn soon
waitCondition(&returning_worker_cond, pMutex);
* ------------------------------------------------------------------------- */
void
-yieldCapability( Capability** pCap )
+yieldCapability( Capability** pCap, Condition *cond )
{
// Pre-condition: pMutex is assumed held, the current thread
// holds the capability pointed to by pCap.
- if ( rts_n_waiting_workers > 0 || passingCapability || !ANY_WORK_TO_DO()) {
+ if ( rts_n_waiting_workers > 0 || !ANY_WORK_FOR_ME(cond)) {
IF_DEBUG(scheduler,
if (rts_n_waiting_workers > 0) {
sched_belch("worker: giving up capability (returning wkr)");
- } else if (passingCapability) {
+ } else if (!EMPTY_RUN_QUEUE()) {
sched_belch("worker: giving up capability (passing capability)");
} else {
sched_belch("worker: giving up capability (no threads to run)");
* 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.
+ * passed to this thread.
* ------------------------------------------------------------------------- */
void
{
// Pre-condition: pMutex is held.
- while ( noCapabilities() ||
- (passingCapability && passTarget != pThreadCond) ||
- !ANY_WORK_TO_DO()) {
+ while ( noCapabilities() || !ANY_WORK_FOR_ME(pThreadCond)) {
IF_DEBUG(scheduler,
sched_belch("worker: wait for capability (cond: %p)",
pThreadCond));
IF_DEBUG(scheduler, sched_belch("worker: get normal capability"));
}
}
- passingCapability = rtsFalse;
grabCapability(pCap);
// Post-condition: pMutex is held and *pCap is held by the current thread
return;
}
-/* ----------------------------------------------------------------------------
- passCapability, passCapabilityToWorker
- ------------------------------------------------------------------------- */
-
-void
-passCapability( Condition *pTargetThreadCond )
-{
- // Pre-condition: pMutex is held and cap is held by the current thread
-
- passTarget = pTargetThreadCond;
- passingCapability = rtsTrue;
- IF_DEBUG(scheduler, sched_belch("worker: passCapability"));
-
- // Post-condition: pMutex is held; cap is still held, but will be
- // passed to the target thread when next released.
-}
-
-void
-passCapabilityToWorker( void )
-{
- // Pre-condition: pMutex is held and cap is held by the current thread
-
- passTarget = NULL;
- passingCapability = rtsTrue;
- IF_DEBUG(scheduler, sched_belch("worker: passCapabilityToWorker"));
-
- // Post-condition: pMutex is held; cap is still held, but will be
- // passed to a worker thread when next released.
-}
-
#endif /* RTS_SUPPORTS_THREADS */
/* ----------------------------------------------------------------------------
threadRunnable ( void )
{
#if defined(RTS_SUPPORTS_THREADS)
- if ( !noCapabilities() && ANY_WORK_TO_DO() && rts_n_waiting_tasks > 0 ) {
- signalCondition(&thread_ready_cond);
+ if ( !noCapabilities() && ANY_WORK_TO_DO() ) {
+ if (!EMPTY_RUN_QUEUE() && run_queue_hd->main != NULL) {
+ signalCondition(&run_queue_hd->main->bound_thread_cond);
+ return;
+ }
+ if (rts_n_waiting_tasks > 0) {
+ signalCondition(&thread_ready_cond);
+ } else {
+ startSchedulerTaskIfNecessary();
+ }
}
- startSchedulerTaskIfNecessary();
#endif
}
projects / ghc-hetmet.git / blobdiff