add forkOnzh_fast symbol

[ghc-hetmet.git] / ghc / rts / Capability.c

diff --git a/ghc/rts/Capability.c b/ghc/rts/Capability.c
index a4380e7..51a42ef 100644 (file)
--- a/ghc/rts/Capability.c
+++ b/ghc/rts/Capability.c
@@ -44,7 +44,7 @@ STATIC_INLINE rtsBool
 globalWorkToDo (void)
 {
     return blackholes_need_checking
-       || interrupted
+       || sched_state >= SCHED_INTERRUPTING
        ;
 }
 #endif
@@ -53,19 +53,26 @@ globalWorkToDo (void)
 STATIC_INLINE rtsBool
 anyWorkForMe( Capability *cap, Task *task )
 {
-    // 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 (!emptyRunQueue(cap)) {
-       if (cap->run_queue_hd->bound == NULL) {
-           return (task->tso == NULL);
-       } else {
-           return (cap->run_queue_hd->bound == task);
-       }
-    } else if (task->tso == NULL && !emptySparkPoolCap(cap)) {
-       return rtsTrue;
+    if (task->tso != NULL) {
+       // A bound task only runs if its thread is on the run queue of
+       // the capability on which it was woken up.  Otherwise, we
+       // can't be sure that we have the right capability: the thread
+       // might be woken up on some other capability, and task->cap
+       // could change under our feet.
+       return !emptyRunQueue(cap) && cap->run_queue_hd->bound == task;
+    } else {
+       // A vanilla worker task runs if either there is a lightweight
+       // thread at the head of the run queue, or the run queue is
+       // empty and (there are sparks to execute, or there is some
+       // other global condition to check, such as threads blocked on
+       // blackholes).
+       if (emptyRunQueue(cap)) {
+           return !emptySparkPoolCap(cap)
+               || !emptyWakeupQueue(cap)
+               || globalWorkToDo();
+       } else
+           return cap->run_queue_hd->bound == NULL;
     }
-    return globalWorkToDo();
 }
 #endif
 
@@ -130,6 +137,8 @@ initCapability( Capability *cap, nat i )
     cap->suspended_ccalling_tasks = NULL;
     cap->returning_tasks_hd = NULL;
     cap->returning_tasks_tl = NULL;
+    cap->wakeup_queue_hd    = END_TSO_QUEUE;
+    cap->wakeup_queue_tl    = END_TSO_QUEUE;
 #endif
 
     cap->f.stgGCEnter1     = (F_)__stg_gc_enter_1;
@@ -281,7 +290,7 @@ releaseCapability_ (Capability* cap)
        // is interrupted, we only create a worker task if there
        // are threads that need to be completed.  If the system is
        // shutting down, we never create a new worker.
-       if (!shutting_down_scheduler) {
+       if (sched_state < SCHED_SHUTTING_DOWN || !emptyRunQueue(cap)) {
            IF_DEBUG(scheduler,
                     sched_belch("starting new worker on capability %d", cap->no));
            startWorkerTask(cap, workerStart);
@@ -291,7 +300,8 @@ releaseCapability_ (Capability* cap)
 
     // If we have an unbound thread on the run queue, or if there's
     // anything else to do, give the Capability to a worker thread.
-    if (!emptyRunQueue(cap) || !emptySparkPoolCap(cap) || globalWorkToDo()) {
+    if (!emptyRunQueue(cap) || !emptyWakeupQueue(cap)
+             || !emptySparkPoolCap(cap) || globalWorkToDo()) {
        if (cap->spare_workers) {
            giveCapabilityToTask(cap,cap->spare_workers);
            // The worker Task pops itself from the queue;
@@ -497,6 +507,37 @@ yieldCapability (Capability** pCap, Task *task)
 }
 
 /* ----------------------------------------------------------------------------
+ * Wake up a thread on a Capability.
+ *
+ * This is used when the current Task is running on a Capability and
+ * wishes to wake up a thread on a different Capability.
+ * ------------------------------------------------------------------------- */
+
+void
+wakeupThreadOnCapability (Capability *cap, StgTSO *tso)
+{
+    ASSERT(tso->cap == cap);
+    ASSERT(tso->bound ? tso->bound->cap == cap : 1);
+
+    ACQUIRE_LOCK(&cap->lock);
+    if (cap->running_task == NULL) {
+       // nobody is running this Capability, we can add our thread
+       // directly onto the run queue and start up a Task to run it.
+       appendToRunQueue(cap,tso);
+
+       // start it up
+       cap->running_task = myTask(); // precond for releaseCapability_()
+       releaseCapability_(cap);
+    } else {
+       appendToWakeupQueue(cap,tso);
+       // someone is running on this Capability, so it cannot be
+       // freed without first checking the wakeup queue (see
+       // releaseCapability_).
+    }
+    RELEASE_LOCK(&cap->lock);
+}
+
+/* ----------------------------------------------------------------------------
  * prodCapabilities
  *
  * Used to indicate that the interrupted flag is now set, or some
@@ -570,7 +611,7 @@ shutdownCapability (Capability *cap, Task *task)
 {
     nat i;
 
-    ASSERT(interrupted && shutting_down_scheduler);
+    ASSERT(sched_state == SCHED_SHUTTING_DOWN);
 
     task->cap = cap;