Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753609AbXLEUyR (ORCPT ); Wed, 5 Dec 2007 15:54:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751519AbXLEUyD (ORCPT ); Wed, 5 Dec 2007 15:54:03 -0500 Received: from ccs17.jlab.org ([129.57.35.82]:46374 "EHLO ccs17.jlab.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751499AbXLEUyD (ORCPT ); Wed, 5 Dec 2007 15:54:03 -0500 Message-ID: <47570FE7.6030407@jlab.org> Date: Wed, 05 Dec 2007 15:53:59 -0500 From: Jie Chen Organization: Jefferson Lab User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Peter Zijlstra CC: linux-kernel@vger.kernel.org, Eric Dumazet , Ingo Molnar , Simon Holm Th??gersen Subject: Re: Possible bug from kernel 2.6.22 and above References: <4744966C.900@jlab.org> <1196887002.6353.19.camel@lappy> In-Reply-To: <1196887002.6353.19.camel@lappy> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1588 Lines: 44 Peter Zijlstra wrote: > On Wed, 2007-11-21 at 15:34 -0500, Jie Chen wrote: > >> It is clearly that the synchronization overhead increases as the number >> of threads increases in the kernel 2.6.21. But the synchronization >> overhead actually decreases as the number of threads increases in the >> kernel 2.6.23.8 (We observed the same behavior on kernel 2.6.22 as >> well). This certainly is not a correct behavior. The kernels are >> configured with CONFIG_SMP, CONFIG_NUMA, CONFIG_SCHED_MC, >> CONFIG_PREEMPT_NONE, CONFIG_DISCONTIGMEM set. The complete kernel >> configuration file is in the attachment of this e-mail. >> >> From what we have read, there was a new scheduler (CFS) appeared from >> 2.6.22. We are not sure whether the above behavior is caused by the new >> scheduler. > > If I read this correctly, you say that: .22 is the first bad one right? > > The new scheduler (CFS) was introduced in .23, so it seems another > change would be responsible for this. > > > Hi, Peter: Yes. We did observe this in 2.6.22. Thank you. -- ############################################### Jie Chen Scientific Computing Group Thomas Jefferson National Accelerator Facility 12000, Jefferson Ave. Newport News, VA 23606 (757)269-5046 (office) (757)269-6248 (fax) chen@jlab.org ############################################### -- 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/