From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262303AbVCILOS (ORCPT ); Wed, 9 Mar 2005 06:14:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262300AbVCILOS (ORCPT ); Wed, 9 Mar 2005 06:14:18 -0500 Received: from one.firstfloor.org ([213.235.205.2]:65446 "EHLO one.firstfloor.org") by vger.kernel.org with ESMTP id S262304AbVCILL2 (ORCPT ); Wed, 9 Mar 2005 06:11:28 -0500 To: suparna@in.ibm.com Cc: Andrew Morton , Badari Pulavarty , linux-aio@kvack.org, linux-kernel@vger.kernel.org Subject: Re: aio stress panic on 2.6.11-mm1 References: <20050308170107.231a145c.akpm@osdl.org> <1110327267.24286.139.camel@dyn318077bld.beaverton.ibm.com> <18744.1110364438@redhat.com> <20050309110404.GA4088@in.ibm.com> From: Andi Kleen Date: Wed, 09 Mar 2005 12:11:26 +0100 In-Reply-To: <20050309110404.GA4088@in.ibm.com> (Suparna Bhattacharya's message of "Wed, 9 Mar 2005 16:34:04 +0530") 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=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Suparna Bhattacharya writes: > Any sense of how costly it is to use spin_lock_irq's vs spin_lock > (across different architectures) ? Isn't rwsem used very widely ? On P4s cli/sti is quite costly, let's says 100+ cycles. That is mostly because it synchronizes the CPU partly. The Intel tables say 26/36 cycles latency, but in practice it seems to take longer because of the synchronization. I would assume this is the worst case, everywhere else it should be cheaper (except perhaps in some virtualized environments) On P-M and AMD K7/K8 it is only a few cycles difference. -Andi