From 5b5b3ce352dcd6a4ae1a5b295aea13487d035418 Mon Sep 17 00:00:00 2001
From: simonmar <unknown>
Date: Thu, 26 Feb 2004 16:21:36 +0000
Subject: [PATCH] [project @ 2004-02-26 16:21:36 by simonmar] merge rev.
 1.6.2.3 from ghc-6-2-branch

---
 ghc/rts/win32/AwaitEvent.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/ghc/rts/win32/AwaitEvent.c b/ghc/rts/win32/AwaitEvent.c
index 92a84bc..edf65df 100644
--- a/ghc/rts/win32/AwaitEvent.c
+++ b/ghc/rts/win32/AwaitEvent.c
@@ -20,6 +20,10 @@
 #include "Capability.h"
 #endif
 
+// Used to avoid calling abandonRequestWait() if we don't need to.
+// Protected by sched_mutex.
+static nat workerWaitingForRequests = 0;
+
 void
 awaitEvent(rtsBool wait)
 {
@@ -38,9 +42,11 @@ awaitEvent(rtsBool wait)
   do {
     /* Try to de-queue completed IO requests
      */
+    workerWaitingForRequests = 1;
     RELEASE_LOCK(&sched_mutex);
     ret = awaitRequests(wait);
     ACQUIRE_LOCK(&sched_mutex);
+    workerWaitingForRequests = 0;
     if (!ret) { 
       return; /* still hold the lock */
     }
@@ -64,7 +70,8 @@ awaitEvent(rtsBool wait)
 void
 wakeBlockedWorkerThread()
 {
-  abandonRequestWait();
+    if (workerWaitingForRequests) {
+	abandonRequestWait();
+    }
 }
 #endif
-
-- 
1.7.10.4