From 909f31872a0e5e5b8ec5cc49b22ae661777a2fbc Mon Sep 17 00:00:00 2001
From: Dmitriy Vyukov <dvyukov@google.com>
Date: Tue, 12 Jul 2011 01:23:58 -0400
Subject: runtime: eliminate false sharing on random number generators Use
 machine-local random number generator instead of racy global ones.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4674049
---
 src/pkg/runtime/runtime.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

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

diff --git a/src/pkg/runtime/runtime.c b/src/pkg/runtime/runtime.c
index 1a3653f108..83af8dc5e2 100644
--- a/src/pkg/runtime/runtime.c
+++ b/src/pkg/runtime/runtime.c
@@ -588,3 +588,16 @@ runtime·FuncForPC(uintptr pc, void *retf)
 	retf = runtime·findfunc(pc);
 	FLUSH(&retf);
 }
+
+uint32
+runtime·fastrand1(void)
+{
+	uint32 x;
+
+	x = m->fastrand;
+	x += x;
+	if(x & 0x80000000L)
+		x ^= 0x88888eefUL;
+	m->fastrand = x;
+	return x;
+}
-- 
cgit v1.3-5-g9baa