From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 20 Sep 2002 13:26:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 20 Sep 2002 13:26:21 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:58050 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id ; Fri, 20 Sep 2002 13:26:20 -0400 Date: Fri, 20 Sep 2002 19:31:03 +0200 From: Jens Axboe To: Mike Anderson Cc: Dave Hansen , "Bond, Andrew" , linux-kernel@vger.kernel.org Subject: Re: TPC-C benchmark used standard RH kernel Message-ID: <20020920173103.GK936@suse.de> References: <45B36A38D959B44CB032DA427A6E106402D09E43@cceexc18.americas.cpqcorp.net> <3D8A3654.50201@us.ibm.com> <20020920172041.GB1944@beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20020920172041.GB1944@beaverton.ibm.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 20 2002, Mike Anderson wrote: > > Dave Hansen [haveblue@us.ibm.com] wrote: > > Bond, Andrew wrote: > > > This isn't as recent as I would like, but it will give you an idea. > > > Top 75 from readprofile. This run was not using bigpages though. > > > > > > 00000000 total 7872 0.0066 > > > c0105400 default_idle 1367 21.3594 > > > c012ea20 find_vma_prev 462 2.2212 > > > > c0142840 create_bounce 378 1.1250 > > > c0142540 bounce_end_io_read 332 0.9881 > > .. snip.. > > > > Forgive my complete ignorane about TPC-C... Why do you have so much > > idle time? Are you I/O bound? (with that many disks, I sure hope not > > :) ) Or is it as simple as leaving profiling running for a bit before > > or after the benchmark was run? > > The calls to create_bounce and bounce_end_io_read are indications that > some of your IO is being bounced and will not be running a peak > performance. > > This is avoided by using the highmem IO changes which I believe are not > in the standard RH kernel. Unknown if that would address your idle time > question. They benched RHAS iirc, and that has the block-highmem patch. They also had more than 4GB of memory, alas, there is bouncing. That doesn't work on all hardware, and all drivers. -- Jens Axboe