From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1767571AbXCIWcu (ORCPT ); Fri, 9 Mar 2007 17:32:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1767576AbXCIWcu (ORCPT ); Fri, 9 Mar 2007 17:32:50 -0500 Received: from waste.org ([66.93.16.53]:38015 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1767571AbXCIWct (ORCPT ); Fri, 9 Mar 2007 17:32:49 -0500 Date: Fri, 9 Mar 2007 16:20:06 -0600 From: Matt Mackall To: Con Kolivas Cc: Willy Tarreau , linux-kernel , akpm@linux-foundation.org Subject: Re: 2.6.21-rc3-mm1 RSDL results Message-ID: <20070309222006.GJ10394@waste.org> References: <20070309053931.GA10459@waste.org> <20070309213959.GI10394@waste.org> <20070309215716.GK943@1wt.eu> <200703100912.07792.kernel@kolivas.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200703100912.07792.kernel@kolivas.org> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 10, 2007 at 09:12:07AM +1100, Con Kolivas wrote: > On Saturday 10 March 2007 08:57, Willy Tarreau wrote: > > 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 ! > > Good idea. 2.6.20+RSDL+tickfix+noyield behaves more or less the same under make -j5 as 2.6.21-rc3-mm1. A bit worse, perhaps. There's no tickless on 2.6.20, so that could explain that. -- Mathematics is the supreme nostalgia of our time.