Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S272929AbTG3O0l (ORCPT ); Wed, 30 Jul 2003 10:26:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S272914AbTG3OXT (ORCPT ); Wed, 30 Jul 2003 10:23:19 -0400 Received: from nat9.steeleye.com ([65.114.3.137]:38663 "EHLO hancock.sc.steeleye.com") by vger.kernel.org with ESMTP id S272894AbTG3OVR (ORCPT ); Wed, 30 Jul 2003 10:21:17 -0400 Subject: Re: [RFC] block layer support for DMA IOMMU bypass mode II From: James Bottomley To: Grant Grundler Cc: Andi Kleen , davem@redhat.com, Alan Cox , Jens Axboe , suparna@in.ibm.com, Linux Kernel , alex_williamson@hp.com, bjorn_helgaas@hp.com In-Reply-To: <20030730044256.GA1974@dsl2.external.hp.com> References: <20030708213427.39de0195.ak@suse.de> <20030708.150433.104048841.davem@redhat.com> <20030708222545.GC6787@dsl2.external.hp.com> <20030708.152314.115928676.davem@redhat.com> <20030723114006.GA28688@dsl2.external.hp.com> <20030728131513.5d4b1bd3.ak@suse.de> <20030730044256.GA1974@dsl2.external.hp.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8 (1.0.8-9) Date: 30 Jul 2003 09:20:52 -0500 Message-Id: <1059574857.1849.7.camel@mulgrave> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 978 Lines: 23 On Tue, 2003-07-29 at 23:42, Grant Grundler wrote: > On Mon, Jul 28, 2003 at 01:15:13PM +0200, Andi Kleen wrote: > > Run it with 100-500 users (reaim -f workfile... -s 100 -e 500 -i 100) > > jejb was wondering if 4k pages would cause different behaviors becuase > of file system vs page size (4k vs 16k). ia64 uses 16k by default. > I've rebuilt the kernel with 4k page size and VMERGE != 0. > The substantially worse performance feels like a rat hole because > of 4x pressure on CPU TLB. OK, I admit it, it was a rat hole. Provided reaim uses large files, we should only get block<->page fragmentation at the edges, and obviously, reaim has to use large files otherwise it's not testing the virtual merging properly... James - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/