Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759618AbXJDTcx (ORCPT ); Thu, 4 Oct 2007 15:32:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756574AbXJDTco (ORCPT ); Thu, 4 Oct 2007 15:32:44 -0400 Received: from mx1.redhat.com ([66.187.233.31]:60202 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754349AbXJDTco (ORCPT ); Thu, 4 Oct 2007 15:32:44 -0400 Message-ID: <47053FC7.2070308@redhat.com> Date: Thu, 04 Oct 2007 15:32:23 -0400 From: Chuck Ebbert Organization: Red Hat User-Agent: Thunderbird 1.5.0.12 (X11/20070719) MIME-Version: 1.0 To: Luca Tettamanti CC: Frans Pop , Willy Tarreau , LKML , =?ISO-8859-1?Q?Ilpo_J=E4rvinen?= , "Alexander E. Patrakov" Subject: Re: Decreasing stime running confuses top References: <200710031433.34504.elendil@planet.nl> <200710032127.42147.elendil@planet.nl> <20071003202446.GQ10199@1wt.eu> <200710040132.45062.elendil@planet.nl> <20071004191921.GA24011@dreamland.darkstar.lan> In-Reply-To: <20071004191921.GA24011@dreamland.darkstar.lan> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1304 Lines: 31 On 10/04/2007 03:19 PM, Luca Tettamanti wrote: >>>>>> The latter seems to be utime ...decreasing. No wonder if >>>>>> arithmetics will give strange results (probably top is using >>>>>> unsigned delta?)... >>>>> Hmm, minor miscounting from my side, stime seems more appropriate... >>>> So, is it normal that stime decreases sometimes or a kernel bug? >>>> /me expects the last... >>> Let me guess... Dual core AMD64 ? >> Nope: Intel(R) Pentium(R) D CPU 3.20GHz > > I just notice the same thing here, with a Core2 Duo (which is supposed > to have synced TSCs) and working HPET. > >> The following may well be relevant. >> With 2.6.22 and early 2.6.23-rc kernels (rc3-rc6) I often had this in my >> kernel log (see http://lkml.org/lkml/2007/9/16/45): >> checking TSC synchronization [CPU#0 -> CPU#1]: >> Measured 248 cycles TSC warp between CPUs, turning off TSC clock. >> Marking TSC unstable due to check_tsc_sync_source failed > > I don't see this though, TSCs are always syncronized between the 2 > cores. > Is CONFIG_VIRT_CPU_ACCOUNTING set? - 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/