From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759720AbYC0MdL (ORCPT ); Thu, 27 Mar 2008 08:33:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755221AbYC0Mc4 (ORCPT ); Thu, 27 Mar 2008 08:32:56 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:43578 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753985AbYC0Mcz (ORCPT ); Thu, 27 Mar 2008 08:32:55 -0400 Date: Thu, 27 Mar 2008 13:32:13 +0100 From: Ingo Molnar To: Jens Axboe Cc: linux-kernel@vger.kernel.org, npiggin@suse.de, paulus@samba.org, tglx@linutronix.de, mingo@redhat.com, tony.luck@intel.com, Alan.Brunelle@hp.com Subject: Re: [PATCH 0/5] Generic smp_call_function(), improvements, and smp_call_function_single() Message-ID: <20080327123213.GC21894@elte.hu> References: <1205927772-31401-1-git-send-email-jens.axboe@oracle.com> <20080321095343.GA21409@elte.hu> <20080321131558.GA15355@kernel.dk> <20080327100802.GD15003@elte.hu> <20080327103707.GH12346@kernel.dk> <20080327104359.GC26725@elte.hu> <20080327120244.GL12346@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080327120244.GL12346@kernel.dk> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jens Axboe wrote: > > i'd love to be able to run/pull something simple that enables me to > > replicate the measurements you did on a generic PC [without having > > to hit any real IO hardware which would put any context switching > > effects down into the noise category]. > > You can pull io-cpu-affinity or io-cpu-affinity-kthread from > git://git.kernel.dk/linux-2.6-block.git - or just see the two attached > patches, apply either one to current -git to test it. another stupid question: what should i run in user-space to replicate your "3 usecs versus 2 usecs" result? io-affinity-ipi.patch seems to have no self-benchmarking capability at first sight. (I'd rather not try and cook up anything myself - i'd like to reproduce the workload you think is relevant for your IO affinity purposes.) Best would be to have a Kconfig based self-test that just runs during bootup if i boot a bzImage. (laziness rules - and this way i could also track performance regressions more easily, by looking at historic serial logs.) Ingo