From 68572644576be5f1f7121428755e7d8af5b7044c Mon Sep 17 00:00:00 2001
From: Dmitriy Vyukov <dvyukov@google.com>
Date: Fri, 19 Jul 2013 17:45:34 +0400
Subject: [PATCH] runtime: prevent sysmon from polling network excessivly If
 the network is not polled for 10ms, sysmon starts polling network on every
 iteration (every 20us) until another thread blocks in netpoll. Fixes #5922.

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/11569043
---
 src/pkg/runtime/proc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index fe32f2c28b0..18ddce80184 100644
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -2098,6 +2098,7 @@ sysmon(void)
 		lastpoll = runtime·atomicload64(&runtime·sched.lastpoll);
 		now = runtime·nanotime();
 		if(lastpoll != 0 && lastpoll + 10*1000*1000 > now) {
+			runtime·cas64(&runtime·sched.lastpoll, lastpoll, now);
 			gp = runtime·netpoll(false);  // non-blocking
 			injectglist(gp);
 		}