From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vadim Rozenfeld Subject: Re: Binary Windows guest drivers are released Date: Fri, 25 Sep 2009 09:52:06 +0300 Message-ID: <4ABC6896.5040805@redhat.com> References: <00be01ca3d18$d5820d60$80862820$@com> <3b1f68ef0909241338n2a88b332u585697a3452acdee@mail.gmail.com> <90eb1dc70909241359i41ba8d9rdcb8364289d740db@mail.gmail.com> <4ABBDF77.2060106@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Javier Guerra , Kenni Lund , Yan Vugenfirer , kvm@vger.kernel.org To: dlaor@redhat.com Return-path: Received: from mx1.redhat.com ([209.132.183.28]:25749 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751241AbZIYGwJ (ORCPT ); Fri, 25 Sep 2009 02:52:09 -0400 In-Reply-To: <4ABBDF77.2060106@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 09/25/2009 12:07 AM, Dor Laor wrote: > On 09/24/2009 11:59 PM, Javier Guerra wrote: >> On Thu, Sep 24, 2009 at 3:38 PM, Kenni Lund wrote: >>> I've done some benchmarking with the drivers on Windows XP SP3 32bit, >>> but it seems like using the VirtIO drivers are slower than the IDE >>> drivers in >>> (almost) all cases. Perhaps I've missed something or does the driver >>> still >>> need optimization? >> >> very interesting! >> >> it seems that IDE wins on all the performance numbers, but VirtIO >> always has lower CPU utilization. i guess this is guest CPU %, right? >> it would also be interesting to compare the CPU usage from the host >> point of view, since a lower 'off-guest' CPU usage is very important >> for scaling to many guests doing I/O. >> > > Can you re-try it with setting the host ioscheduler to deadline? > Virtio backend (thread pool) is sensitive for it. > > These drivers are mainly tweaked for win2k3 and win2k8. We once had > queue depth settings in the driver, not sure we still have it, Vadim, > can you add more info? > > Also virtio should provide IO parallelism as opposed to IDE. I don't > think your test test it. Virtio can provide more virtual drives than > the max 4 that ide offers. > > Dor Windows XP 32-bit virtio block driver was created from our mainline code almost for fun. Not like our mainline code, which is STORPORT oriented, it is a SCSIPORT (!!!!) mini-port driver. SCSIPORT has never been known as I/O optimized storage stack. SCSIPORT architecture is almost dead officially. Windows XP 32-bit has no support for STORPORT or virtual storage stack. Developing monolithic disk driver, which will sit right on top of virtio-blk PCI device, looks like the one way to have some kind of high throughput storage for Windows XP 32-bit. Regards, Vadim.