From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] fib: avoid false sharing on fib_table_hash Date: Sat, 16 Oct 2010 11:56:10 -0700 (PDT) Message-ID: <20101016.115610.48524281.davem@davemloft.net> References: <1286994123.3876.1137.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: eric.dumazet@gmail.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:35260 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753879Ab0JPSzr (ORCPT ); Sat, 16 Oct 2010 14:55:47 -0400 In-Reply-To: <1286994123.3876.1137.camel@edumazet-laptop> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet Date: Wed, 13 Oct 2010 20:22:03 +0200 > While doing profile analysis, I found fib_hash_table was sometime in a > cache line shared by a possibly often written kernel structure. > > (CONFIG_IP_ROUTE_MULTIPATH || !CONFIG_IPV6_MULTIPLE_TABLES) > > It's hard to detect because not easily reproductible. > > Make sure we allocate a full cache line to keep this shared in all cpus > caches. > > Signed-off-by: Eric Dumazet Applied.