Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756925Ab3GDU1Y (ORCPT ); Thu, 4 Jul 2013 16:27:24 -0400 Received: from www.linutronix.de ([62.245.132.108]:42375 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751984Ab3GDU1X (ORCPT ); Thu, 4 Jul 2013 16:27:23 -0400 Date: Thu, 4 Jul 2013 22:27:19 +0200 (CEST) From: Thomas Gleixner To: Davidlohr Bueso cc: Alex Shi , hpa@linux.intel.com, tim.c.chen@linux.intel.com, linux-kernel@vger.kernel.org, andi.kleen@intel.com, a.p.zijlstra@chello.nl, mingo@elte.hu Subject: Re: [URGENT rfc patch 0/3] tsc clocksource bug fix In-Reply-To: <1372961512.8728.32.camel@buesod1.americas.hpqcorp.net> Message-ID: References: <1372916056-24301-1-git-send-email-alex.shi@intel.com> <1372961512.8728.32.camel@buesod1.americas.hpqcorp.net> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1871 Lines: 51 On Thu, 4 Jul 2013, Davidlohr Bueso wrote: > On Thu, 2013-07-04 at 13:00 +0200, Thomas Gleixner wrote: > > On Thu, 4 Jul 2013, Alex Shi wrote: > > > > > We find some benchmarks drop a lot on tip/sched/core on many Intel boxes, > > > like oltp, tbench, hackbench etc. and bisected the commit 5d33b883ae > > > cause this regression. Due to this commit, the clocksource was changed > > > to hpet from tsc even tsc will be set CLOCK_SOURCE_VALID_FOR_HRES later > > > in clocksource_watchdog. > > > > 5d33b883ae is not in tip/sched/core. So what are you testing and > > bisecting? > > I think he's referring to: > > commit 5d33b883aed81c6fbcd09c6f7c3619eee850a7e2 I know what he is referring to. He explicitly mentions this commit: > > > like oltp, tbench, hackbench etc. and bisected the commit 5d33b883ae What I was pointing out that he was referring to tip sched/core at the same time > > > We find some benchmarks drop a lot on tip/sched/core on many Intel boxes, And that branch does NOT have that commit included. So how can you see a regression on a branch caused by a commit NOT included into that branch? The offending commit is in tip timers/core and not in tip sched/core. What I'm wanted to say is, that we need a proper description of problems and not some random association. It tricked you to assume, that I'm not able to figure it out myself :) See? These things are complex and subtle, so we need precise descriptions and not some sloppy semi correct data. I'm well aware of the issue and with Peters help I got a reasonable explanation for it. A proper fix is about to be sent out. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/