From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933404AbXCIVwi (ORCPT ); Fri, 9 Mar 2007 16:52:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2993149AbXCIVwi (ORCPT ); Fri, 9 Mar 2007 16:52:38 -0500 Received: from waste.org ([66.93.16.53]:39017 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933408AbXCIVwh (ORCPT ); Fri, 9 Mar 2007 16:52:37 -0500 Date: Fri, 9 Mar 2007 15:39:59 -0600 From: Matt Mackall To: Con Kolivas Cc: linux-kernel , akpm@linux-foundation.org Subject: Re: 2.6.21-rc3-mm1 RSDL results Message-ID: <20070309213959.GI10394@waste.org> References: <20070309053931.GA10459@waste.org> <20070309204623.GE10394@waste.org> <200703100807.43582.kernel@kolivas.org> <200703100819.18354.kernel@kolivas.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200703100819.18354.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 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. -- Mathematics is the supreme nostalgia of our time.