Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753372Ab0ADNCo (ORCPT ); Mon, 4 Jan 2010 08:02:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753358Ab0ADNCn (ORCPT ); Mon, 4 Jan 2010 08:02:43 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:40317 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753268Ab0ADNCn (ORCPT ); Mon, 4 Jan 2010 08:02:43 -0500 Subject: Re: volano ~30% regression with 2.6.33-rc1 & -rc2 From: Peter Zijlstra To: Mike Galbraith Cc: Arjan van de Ven , Lin Ming , lkml , "Zhang, Yanmin" In-Reply-To: <1262609854.9734.56.camel@marge.simson.net> References: <1262592958.22471.104.camel@minggr.sh.intel.com> <20100104044024.5390ff1c@infradead.org> <1262609854.9734.56.camel@marge.simson.net> Content-Type: text/plain; charset="UTF-8" Date: Mon, 04 Jan 2010 14:02:03 +0100 Message-ID: <1262610123.6408.120.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1317 Lines: 29 On Mon, 2010-01-04 at 13:57 +0100, Mike Galbraith wrote: > On Mon, 2010-01-04 at 04:40 -0800, Arjan van de Ven wrote: > > On Mon, 04 Jan 2010 16:15:58 +0800 > > Lin Ming wrote: > > > > > Mike & Peter, > > > > > > Compared with 2.6.32, volano has ~30% regression with 2.6.33-rc1 & > > > -rc2. Testing machine: Tigerton Xeon, 16cpus(4P/4Core), 16G memory > > > > did this show up only on this cpu? > > (since this is a multi-core-without-shared-cache cpu, it could be that > > we get the topology wrong and think cores share cache where they don't) > > My fault for using PREFER_SIBLING I guess. However, I do wonder why in > the heck we set that at the CPU domain level. Siblings lie northward. Ah, PREFER_SIBLING means prefer sibling domain, not sibling thread. Its set at the CPU (really socket) level so make tasks spread over sockets first, so that there is no competition for the socket wide resources. Your change is sane, but we really want a more extensive sched domain tree in the near future, reflecting the full machine topology. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/