From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755154AbXGaI5g (ORCPT ); Tue, 31 Jul 2007 04:57:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752553AbXGaI53 (ORCPT ); Tue, 31 Jul 2007 04:57:29 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:35491 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752343AbXGaI52 (ORCPT ); Tue, 31 Jul 2007 04:57:28 -0400 Date: Tue, 31 Jul 2007 10:57:13 +0200 From: Ingo Molnar To: Peter Zijlstra Cc: Kasper Sandberg , Linus Torvalds , Linux Kernel Mailing List , ck@vds.kolivas.org Subject: Re: SD still better than CFS for 3d ?(was Re: 2.6.23-rc1) Message-ID: <20070731085713.GA15136@elte.hu> References: <1185536610.502.8.camel@localhost> <20070729170641.GA26220@elte.hu> <1185839164.27166.7.camel@localhost> <1185863461.3092.4.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1185863461.3092.4.camel@twins> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: 1.0 X-ELTE-SpamLevel: s X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=1.0 required=5.9 tests=BAYES_50 autolearn=no SpamAssassin version=3.0.3 1.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Peter Zijlstra wrote: > On Tue, 2007-07-31 at 01:46 +0200, Kasper Sandberg wrote: > > > could perhaps be filesystem related, i have my maildir(extremely > > large) on reiserfs, and /home on xfs. what my mail client will do is > > download mail, spamasassin it(loading database from home), then it > > will put to imap server placing it on reiserfs, and then a "local" > > copy in my home. > > Ooh, do you perchance have PREEMPT_BKL=y? > > If so, try on another filesystem than reiserfs (or disable > PREEMPT_BKL, but that is obviously the lesser of the two choices). > > Ingo traced a 1+ second latency at my end to BKL priority inversion > between tty and reiserfs. ah, indeed, that makes quite a bit of sense. Almost all of the Reiser3 code runs under the BKL, and the only other major kernel infrastructure that has BKL dependencies is the TTY code. Kasper, as a debugging matter, could you try to move that spamassassin workload off into a non-Reiser3 filesystem and/or disable PREEMPT_BKL? If that makes a noticeable difference (for the better ;) then we can continue figuring out what's happening exactly. Ingo