From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932789AbWLNUWU (ORCPT ); Thu, 14 Dec 2006 15:22:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932827AbWLNUWT (ORCPT ); Thu, 14 Dec 2006 15:22:19 -0500 Received: from brick.kernel.dk ([62.242.22.158]:4226 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932790AbWLNUWS (ORCPT ); Thu, 14 Dec 2006 15:22:18 -0500 Date: Thu, 14 Dec 2006 21:23:44 +0100 From: Jens Axboe To: "Chen, Kenneth W" Cc: "'linux-kernel'" Subject: Re: [patch] speed up single bio_vec allocation Message-ID: <20061214202343.GK5010@kernel.dk> References: <000001c71b16$4ca91b90$d134030a@amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000001c71b16$4ca91b90$d134030a@amr.corp.intel.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 08 2006, Chen, Kenneth W wrote: > > Chen, Kenneth wrote on Wednesday, December 06, 2006 10:20 AM > > > Jens Axboe wrote on Wednesday, December 06, 2006 2:09 AM > > > This is what I had in mind, in case it wasn't completely clear. Not > > > tested, other than it compiles. Basically it eliminates the small > > > bio_vec pool, and grows the bio by 16-bytes on 64-bit archs, or by > > > 12-bytes on 32-bit archs instead and uses the room at the end for the > > > bio_vec structure. > > > > Yeah, I had a very similar patch queued internally for the large benchmark > > measurement. I will post the result as soon as I get it. > > > Jens, this improves 0.25% on our db transaction processing benchmark setup. > The patch tested is (on top of 2.6.19): > http://marc.theaimsgroup.com/?l=linux-kernel&m=116539972229021&w=2 Ok, well it's not much but if it's significant it's not too bad either :-) Some tests I ran locally showed it being _slower_, which is a little odd. They were basically hammering requests through the block layer with a null end. -- Jens Axboe