Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262138AbVCIX03 (ORCPT ); Wed, 9 Mar 2005 18:26:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262533AbVCIXY7 (ORCPT ); Wed, 9 Mar 2005 18:24:59 -0500 Received: from one.firstfloor.org ([213.235.205.2]:43175 "EHLO one.firstfloor.org") by vger.kernel.org with ESMTP id S262259AbVCIXXK (ORCPT ); Wed, 9 Mar 2005 18:23:10 -0500 To: "Chen, Kenneth W" Cc: , Subject: Re: Direct io on block device has performance regression on 2.6.x kernel References: <200503092218.j29MICg26503@unix-os.sc.intel.com> From: Andi Kleen Date: Thu, 10 Mar 2005 00:23:09 +0100 In-Reply-To: <200503092218.j29MICg26503@unix-os.sc.intel.com> (Kenneth W. Chen's message of "Wed, 9 Mar 2005 14:18:12 -0800") Message-ID: User-Agent: Gnus/5.110002 (No Gnus v0.2) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 759 Lines: 17 "Chen, Kenneth W" writes: > > Just to clarify here, these data need to be taken at grain of salt. A > high count in _spin_unlock_* functions do not automatically points to > lock contention. It's one of the blind spot syndrome with timer based > profile on ia64. There are some lock contentions in 2.6 kernel that > we are staring at. Please do not misinterpret the number here. Why don't you use oprofile?>? It uses NMIs and can profile "inside" interrupt disabled sections. -Andi - 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/