From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Mon, 24 Apr 2017 14:26:41 +0000 (+0300)
Subject: runtime: align mcentral by cache line size
X-Git-Tag: go1.9beta1~463
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=259d60995d735523fc25939c35847538eb0d0670;p=gostls13.git

runtime: align mcentral by cache line size

This may improve perormance during concurrent access
to mheap.central array from multiple CPU cores.

Change-Id: I8f48dd2e72aa62e9c32de07ae60fe552d8642782
Reviewed-on: https://go-review.googlesource.com/41550
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
---

diff --git a/src/runtime/mheap.go b/src/runtime/mheap.go
index c2d5b46223..82dc599b97 100644
--- a/src/runtime/mheap.go
+++ b/src/runtime/mheap.go
@@ -121,7 +121,7 @@ type mheap struct {
 	// gets its own cache line.
 	central [_NumSizeClasses]struct {
 		mcentral mcentral
-		pad      [sys.CacheLineSize]byte
+		pad      [sys.CacheLineSize - unsafe.Sizeof(mcentral{})%sys.CacheLineSize]byte
 	}
 
 	spanalloc             fixalloc // allocator for span*