From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1767579AbXCIWmE (ORCPT ); Fri, 9 Mar 2007 17:42:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1767580AbXCIWmE (ORCPT ); Fri, 9 Mar 2007 17:42:04 -0500 Received: from waste.org ([66.93.16.53]:33568 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1767579AbXCIWmB (ORCPT ); Fri, 9 Mar 2007 17:42:01 -0500 Date: Fri, 9 Mar 2007 16:29:23 -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: <20070309222923.GK10394@waste.org> References: <20070309053931.GA10459@waste.org> <20070309213959.GI10394@waste.org> <200703100857.12939.kernel@kolivas.org> <200703100918.05547.kernel@kolivas.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200703100918.05547.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 09:18:05AM +1100, Con Kolivas wrote: > On Saturday 10 March 2007 08:57, Con Kolivas wrote: > > On Saturday 10 March 2007 08:39, 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. > > > > Hmm it must be those deep pipes again then. I removed any quirks testing > > for those from mainline as I suspected it would be ok. Guess I"m wrong. > > I shouldn't blame this straight up though if NO_HZ makes it better. Something > else is going wrong... wtf though? Just so we're clear, dynticks has only 'fixed' the single non-parallel make load so far. -- Mathematics is the supreme nostalgia of our time.