From 2db08122e36c137a36ab9768ffceae332c1695f1 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Sat, 9 Jan 2010 09:47:45 -0800
Subject: runtime: check for preemption due to garbage collection 	in
 various already expensive routines.

helps keep cpu utilization up when GOMAXPROCS > 1,
but not a full solution.

http://groups.google.com/group/golang-nuts/t/7a9535c4136d3e2

R=r
CC=golang-dev
http://codereview.appspot.com/184043
---
 src/pkg/runtime/proc.c | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'src/pkg/runtime/proc.c')

diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index 6ac4090eb..6324b4be4 100644
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -14,6 +14,8 @@ G	g0;	// idle goroutine for m0
 
 static	int32	debug	= 0;
 
+int32	gcwaiting;
+
 // Go scheduler
 //
 // The go scheduler's job is to match ready-to-run goroutines (`g's)
@@ -362,6 +364,7 @@ void
 stoptheworld(void)
 {
 	lock(&sched);
+	gcwaiting = 1;
 	sched.mcpumax = 1;
 	while(sched.mcpu > 1) {
 		noteclear(&sched.stopped);
@@ -379,6 +382,7 @@ void
 starttheworld(void)
 {
 	lock(&sched);
+	gcwaiting = 0;
 	sched.mcpumax = sched.gomaxprocs;
 	matchmg();
 	unlock(&sched);
-- 
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