From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030628AbXDZO2e (ORCPT ); Thu, 26 Apr 2007 10:28:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031045AbXDZO2e (ORCPT ); Thu, 26 Apr 2007 10:28:34 -0400 Received: from sceptre.pobox.com ([207.106.133.20]:39992 "EHLO sceptre.pobox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030628AbXDZO2d (ORCPT ); Thu, 26 Apr 2007 10:28:33 -0400 Message-ID: <4630B70D.7070409@hp.com> Date: Thu, 26 Apr 2007 10:28:29 -0400 From: "Alan D. Brunelle" Reply-To: Alan.Brunelle@pobox.com User-Agent: Thunderbird 1.5.0.10 (X11/20070403) MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Cc: Jens Axboe Subject: Re: [PATCH 5/15] cfq-iosched: speed up rbtree handling References: <11774025432481-git-send-email-jens.axboe@oracle.com> <11774025432403-git-send-email-jens.axboe@oracle.com> <462F7AD9.8020300@hp.com> <20070425171539.GE4730@kernel.dk> <20070425175047.GF4730@kernel.dk> <20070425180813.GI4730@kernel.dk> In-Reply-To: <20070425180813.GI4730@kernel.dk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jens Axboe wrote: > On Wed, Apr 25 2007, Jens Axboe wrote: >> On Wed, Apr 25 2007, Jens Axboe wrote: >>> On Wed, Apr 25 2007, Alan D. Brunelle wrote: >>>> Hi Jens - >>>> >>>> The attached patch speeds it up even more - I'm finding a >9% reduction >>>> in %system with no loss in IO performance. This just sets the cached >>>> element when the first is looked for. >>> Interesting, good thinking. It should not change the IO pattern, as the >>> end result should be the same. Thanks Alan, will commit! >>> >>> I'll give elevator.c the same treatment, should be even more beneficial. >>> Stay tuned for a test patch. >> Something like this, totally untested (it compiles). I initially wanted >> to fold the cfq addon into the elevator.h provided implementation, but >> that requires more extensive changes. Given how little code it is, I >> think I'll keep them seperate. > > Booted, seems to work fine for me. In a null ended IO test, I get about > a 1-2% speedup for a single queue of depth 64 using libaio. So it's > definitely worth it, will commit. > After longer runs last night, I think the patched elevator code /does/ help (albeit ever so slightly - about 0.6% performance improvement at a 1.1% %system overhead). rkB_s %system Kernel --------- ------- ---------------------------------------------------- 1022942.2 3.69 Original patch + fix to cfq_rb_first 1029087.0 3.73 This patch stream (including fixes to elevator code) Alan