From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031193AbXDZPu0 (ORCPT ); Thu, 26 Apr 2007 11:50:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031287AbXDZPuZ (ORCPT ); Thu, 26 Apr 2007 11:50:25 -0400 Received: from brick.kernel.dk ([80.160.20.94]:7484 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031193AbXDZPuZ (ORCPT ); Thu, 26 Apr 2007 11:50:25 -0400 Date: Thu, 26 Apr 2007 17:46:44 +0200 From: Jens Axboe To: Alan.Brunelle@pobox.com Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/15] cfq-iosched: speed up rbtree handling Message-ID: <20070426154643.GB2017@kernel.dk> 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> <4630B70D.7070409@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4630B70D.7070409@hp.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 26 2007, Alan D. Brunelle wrote: > 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) Ah good, thanks for testing! It's all in the cfq branch now. -- Jens Axboe