X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FThreads.c;h=0dee734baa0edfc15903a437c5e191c266c33067;hb=fff1f6194c3c39de53cd645bda9865fb131b1c68;hp=e8a835bdaeb2bc08c98f429da4fcb74f004320b1;hpb=f4692220c7cbdadaa633f50eb2b30b59edb30183;p=ghc-hetmet.git

diff --git a/rts/Threads.c b/rts/Threads.c
index e8a835b..0dee734 100644
--- a/rts/Threads.c
+++ b/rts/Threads.c
@@ -217,7 +217,12 @@ removeThreadFromDeQueue (Capability *cap,
 void
 tryWakeupThread (Capability *cap, StgTSO *tso)
 {
+    tryWakeupThread_(cap, deRefTSO(tso));
+}
 
+void
+tryWakeupThread_ (Capability *cap, StgTSO *tso)
+{
     traceEventThreadWakeup (cap, tso, tso->cap->no);
 
 #ifdef THREADED_RTS
@@ -279,6 +284,19 @@ unblock:
     // we'll block again.
     tso->why_blocked = NotBlocked;
     appendToRunQueue(cap,tso);
+
+    // We used to set the context switch flag here, which would
+    // trigger a context switch a short time in the future (at the end
+    // of the current nursery block).  The idea is that we have just
+    // woken up a thread, so we may need to load-balance and migrate
+    // threads to other CPUs.  On the other hand, setting the context
+    // switch flag here unfairly penalises the current thread by
+    // yielding its time slice too early.
+    //
+    // The synthetic benchmark nofib/smp/chan can be used to show the
+    // difference quite clearly.
+
+    // cap->context_switch = 1;
 }
 
 /* ----------------------------------------------------------------------------
@@ -291,7 +309,7 @@ migrateThread (Capability *from, StgTSO *tso, Capability *to)
     traceEventMigrateThread (from, tso, to->no);
     // ThreadMigrating tells the target cap that it needs to be added to
     // the run queue when it receives the MSG_TRY_WAKEUP.
-    tso->what_next = ThreadMigrating;
+    tso->why_blocked = ThreadMigrating;
     tso->cap = to;
     tryWakeupThread(from, tso);
 }
@@ -383,6 +401,7 @@ updateThunk (Capability *cap, StgTSO *tso, StgClosure *thunk, StgClosure *val)
     i = thunk->header.info;
     if (i != &stg_BLACKHOLE_info &&
         i != &stg_CAF_BLACKHOLE_info &&
+        i != &__stg_EAGER_BLACKHOLE_info &&
         i != &stg_WHITEHOLE_info) {
         updateWithIndirection(cap, thunk, val);
         return;
@@ -486,8 +505,8 @@ printThreadBlockage(StgTSO *tso)
   case BlockedOnCCall:
     debugBelch("is blocked on an external call");
     break;
-  case BlockedOnCCall_NoUnblockExc:
-    debugBelch("is blocked on an external call (exceptions were already blocked)");
+  case BlockedOnCCall_Interruptible:
+    debugBelch("is blocked on an external call (but may be interrupted)");
     break;
   case BlockedOnSTM:
     debugBelch("is blocked on an STM operation");