From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760392AbXHAHgU (ORCPT ); Wed, 1 Aug 2007 03:36:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754599AbXHAHgJ (ORCPT ); Wed, 1 Aug 2007 03:36:09 -0400 Received: from mail.gmx.net ([213.165.64.20]:41792 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753473AbXHAHgG (ORCPT ); Wed, 1 Aug 2007 03:36:06 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX1/7KHgGExz7VHlqqY1r9qAmQOy4kq9ePjOORNCc/Y cJIyuGwP4iePSr Subject: Re: CFS review From: Mike Galbraith To: Ingo Molnar Cc: Roman Zippel , Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org In-Reply-To: <20070801073042.GB21551@elte.hu> References: <20070711211638.GE18767@one.firstfloor.org> <20070711214649.GK14435@v2.random> <1184302024.6709.11.camel@Homer.simpson.net> <1184389456.6632.13.camel@Homer.simpson.net> <20070801071230.GA16375@elte.hu> <1185953195.6388.21.camel@Homer.simpson.net> <20070801073042.GB21551@elte.hu> Content-Type: text/plain Date: Wed, 01 Aug 2007 09:36:02 +0200 Message-Id: <1185953762.6388.26.camel@Homer.simpson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.8.2 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2007-08-01 at 09:30 +0200, Ingo Molnar wrote: > * Mike Galbraith wrote: > > I haven't been able to reproduce this with any combination of > > features, and massive_intr tweaked to his work/sleep cycle. I notice > > he's collecting stats though, and they look funky. Recompiling. > > yeah, the posted numbers look most weird, but there's a complete lack of > any identification of test environment - so we'll need some more word > >from Roman. Perhaps this was run on some really old box that does not > have a high-accuracy sched_clock()? The patch below should simulate that > scenario on 32-bit x86. > > Ingo > > Index: linux/arch/i386/kernel/tsc.c > =================================================================== > --- linux.orig/arch/i386/kernel/tsc.c > +++ linux/arch/i386/kernel/tsc.c > @@ -110,7 +110,7 @@ unsigned long long native_sched_clock(vo > * very important for it to be as fast as the platform > * can achive it. ) > */ > - if (unlikely(!tsc_enabled && !tsc_unstable)) > +// if (unlikely(!tsc_enabled && !tsc_unstable)) > /* No locking but a rare wrong value is not a big deal: */ > return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ); > Ah, thanks. I noticed that clocksource= went away. I'll test with stats, with and without jiffies resolution. -Mike