From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030576AbXBMAZy (ORCPT ); Mon, 12 Feb 2007 19:25:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030585AbXBMAZy (ORCPT ); Mon, 12 Feb 2007 19:25:54 -0500 Received: from ozlabs.org ([203.10.76.45]:39745 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030576AbXBMAZw (ORCPT ); Mon, 12 Feb 2007 19:25:52 -0500 Subject: Re: [PATCH 7/8] lguest: trivial guest block driver From: Rusty Russell To: Jens Axboe Cc: Andrew Morton , lkml - Kernel Mailing List , virtualization In-Reply-To: <20070212150125.GM3999@kernel.dk> References: <1171251965.10409.28.camel@localhost.localdomain> <1171252113.10409.30.camel@localhost.localdomain> <1171252219.10409.33.camel@localhost.localdomain> <1171252321.10409.36.camel@localhost.localdomain> <1171252405.10409.39.camel@localhost.localdomain> <1171252474.10409.42.camel@localhost.localdomain> <20070212044339.GJ3685@kernel.dk> <1171258034.10409.54.camel@localhost.localdomain> <20070212053204.GB3999@kernel.dk> <1171264167.10409.62.camel@localhost.localdomain> <20070212150125.GM3999@kernel.dk> Content-Type: text/plain Date: Tue, 13 Feb 2007 11:25:05 +1100 Message-Id: <1171326305.19842.36.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2007-02-12 at 16:01 +0100, Jens Axboe wrote: > On Mon, Feb 12 2007, Rusty Russell wrote: > > Thanks Jens!! > > My pleasure, it's not often you get to make that big a performance > improvement with just a little few lines of change :-) *cough* I deliberately leave these low hanging fruit in lguest to encourage people to hack on it. Really. *cough* > I guess you'll take changes to make this driver queuing as well? It's > pretty important for good guest io performance as well. The question is whether the guest or host should queue. If you have multiple guests sharing a disk in the hose, I would think that the host is better off queuing. And this would seem to be the common case. On my todo list is: 1) Implement write barriers, (-> fsync in the host) 2) Make the host userspace program (lguest) async rather than blocking, 3) Allow multiple outstanding requests. Then it should be useful for other hypervisors. Cheers! Rusty. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: Re: [PATCH 7/8] lguest: trivial guest block driver Date: Tue, 13 Feb 2007 11:25:05 +1100 Message-ID: <1171326305.19842.36.camel@localhost.localdomain> References: <1171251965.10409.28.camel@localhost.localdomain> <1171252113.10409.30.camel@localhost.localdomain> <1171252219.10409.33.camel@localhost.localdomain> <1171252321.10409.36.camel@localhost.localdomain> <1171252405.10409.39.camel@localhost.localdomain> <1171252474.10409.42.camel@localhost.localdomain> <20070212044339.GJ3685@kernel.dk> <1171258034.10409.54.camel@localhost.localdomain> <20070212053204.GB3999@kernel.dk> <1171264167.10409.62.camel@localhost.localdomain> <20070212150125.GM3999@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20070212150125.GM3999@kernel.dk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.osdl.org Errors-To: virtualization-bounces@lists.osdl.org To: Jens Axboe Cc: virtualization , Andrew Morton , lkml - Kernel Mailing List List-Id: virtualization@lists.linuxfoundation.org On Mon, 2007-02-12 at 16:01 +0100, Jens Axboe wrote: > On Mon, Feb 12 2007, Rusty Russell wrote: > > Thanks Jens!! > = > My pleasure, it's not often you get to make that big a performance > improvement with just a little few lines of change :-) *cough* I deliberately leave these low hanging fruit in lguest to encourage people to hack on it. Really. *cough* > I guess you'll take changes to make this driver queuing as well? It's > pretty important for good guest io performance as well. The question is whether the guest or host should queue. If you have multiple guests sharing a disk in the hose, I would think that the host is better off queuing. And this would seem to be the common case. On my todo list is: 1) Implement write barriers, (-> fsync in the host) 2) Make the host userspace program (lguest) async rather than blocking, 3) Allow multiple outstanding requests. Then it should be useful for other hypervisors. Cheers! Rusty.