From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933403AbXCIV55 (ORCPT ); Fri, 9 Mar 2007 16:57:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1766786AbXCIV5z (ORCPT ); Fri, 9 Mar 2007 16:57:55 -0500 Received: from 1wt.eu ([62.212.114.60]:1087 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933405AbXCIV5s (ORCPT ); Fri, 9 Mar 2007 16:57:48 -0500 Date: Fri, 9 Mar 2007 22:57:17 +0100 From: Willy Tarreau To: Matt Mackall Cc: Con Kolivas , linux-kernel , akpm@linux-foundation.org Subject: Re: 2.6.21-rc3-mm1 RSDL results Message-ID: <20070309215716.GK943@1wt.eu> References: <20070309053931.GA10459@waste.org> <20070309204623.GE10394@waste.org> <200703100807.43582.kernel@kolivas.org> <200703100819.18354.kernel@kolivas.org> <20070309213959.GI10394@waste.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070309213959.GI10394@waste.org> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 09, 2007 at 03:39:59PM -0600, Matt Mackall wrote: > On Sat, Mar 10, 2007 at 08:19:18AM +1100, Con Kolivas wrote: > > On Saturday 10 March 2007 08:07, Con Kolivas wrote: > > > On Saturday 10 March 2007 07:46, Matt Mackall wrote: > > > > My suspicion is the problem lies in giving too much quanta to > > > > newly-started processes. > > > > > > Ah that's some nice detective work there. Mainline does some rather complex > > > accounting on sched_fork including (possibly) a whole timer tick which rsdl > > > does not do. make forks off continuously so what you say may well be > > > correct. I'll see if I can try to revert to the mainline behaviour in > > > sched_fork (which was obviously there for a reason). > > > > Wow! Thanks Matt. You've found a real bug too. This seems to fix the qemu > > misbehaviour and bitmap errors so far too! Now can you please try this to see > > if it fixes your problem? > > Sorry, it's about the same. I now suspect an accounting glitch involving > pipe wake-ups. > > 5x memload: good > 5x execload: good > 5x forkload: good > 5 parallel makes: mostly good > make -j 5: bad > > So what's different between makes in parallel and make -j 5? Make's > job server uses pipe I/O to control how many jobs are running. Matt, could you check with plain 2.6.20 + Con's patch ? It is possible that he added bugs when porting to -mm, or that someting in -mm causes the trouble. Your experience with -mm seems so much different from mine with mainline, there must be a difference somewhere ! Con, is your patch necessary for mainline patch too ? I see that it should apply, but sometimes -mm may justify changes. Best regards, Willy