From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id A865F6B010E for ; Wed, 13 May 2009 10:46:56 -0400 (EDT) Message-ID: <4A0ADD88.9080705@redhat.com> Date: Wed, 13 May 2009 10:47:36 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 4/4] zone_reclaim_mode is always 0 by default References: <20090513120155.5879.A69D9226@jp.fujitsu.com> <20090513120729.5885.A69D9226@jp.fujitsu.com> In-Reply-To: <20090513120729.5885.A69D9226@jp.fujitsu.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: LKML , linux-mm , Andrew Morton , Christoph Lameter List-ID: KOSAKI Motohiro wrote: > Subject: [PATCH] zone_reclaim_mode is always 0 by default > > Current linux policy is, if the machine has large remote node distance, > zone_reclaim_mode is enabled by default because we've be able to assume to > large distance mean large server until recently. > > Unfrotunately, recent modern x86 CPU (e.g. Core i7, Opeteron) have P2P transport > memory controller. IOW it's NUMA from software view. > > Some Core i7 machine has large remote node distance and zone_reclaim don't > fit desktop and small file server. it cause performance degression. > > Thus, zone_reclaim == 0 is better by default. sorry, HPC gusy. > you need to turn zone_reclaim_mode on manually now. I'll believe that it causes a performance regression with the old zone_reclaim behaviour, however the way you tweaked zone_reclaim should make it behave a lot better, no? -- All rights reversed. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org