From mboxrd@z Thu Jan 1 00:00:00 1970 From: Henrik Holst Subject: Disk Benchmark results, kvm-69 Date: Mon, 26 May 2008 12:56:04 +0200 Message-ID: <1211799364.5779.25.camel@henrik-desktop> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from gv-out-0910.google.com ([216.239.58.191]:58093 "EHLO gv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753463AbYEZK4I (ORCPT ); Mon, 26 May 2008 06:56:08 -0400 Received: by gv-out-0910.google.com with SMTP id e6so1105509gvc.37 for ; Mon, 26 May 2008 03:56:07 -0700 (PDT) Sender: kvm-owner@vger.kernel.org List-ID: We have performed some quick benchmarks against kvm-69 on an Intel Q6600 with 8GB RAM and equipped with 4 SATA drives (Maxtor DiamondMax 10 6V300F0). During these tests we noticed a problem with the virtio block device in where it completely locks the drive after a while when running on a smp guest. The other disks are ok and the guest is working as it should but all access to /dev/vda1 never times out. Also with if=scsi the host would output (during the bonnie++ tests): lsi_scsi: error: PRDERED queue not implemented lsi_scsi: error: Unimplemented message 0x0c Host: 2.6.24-1-amd64 debian testing Guest: 2.6.24-16-server ubuntu 8.04 hdparm -tT /dev/sdb on host: Timing cached reads: 3845.63 MB/sec Timing buffered disk reads: 67.98 MB/sec Qemu invocation (for virtio): qemu-system-x86_64 -m 3072 -smp 4 \ -drive file=ubuntu.img,if=ide,boot=on,media=disk \ -drive file=/dev/sdb,if=virtio,boot=off,cache=off,media=disk Bonnie++ invocation: bonnie++ -r 512 -s 2048 -u root -d /mnt/sdb1/ : Results: --------------------------------------------------------------------------------- Version 1.03b ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP host 2G 60814 81 83149 15 64419 8 85187 99 2394159 100 +++++ +++ guest-ide 2G 65048 89 72621 13 64792 9 84224 99 2311183 99 +++++ +++ guest-scsi 2G 67387 90 73757 13 63783 9 84645 100 2297687 99 +++++ +++ guest-virtio 2G 41564 57 73274 28 62725 27 71656 85 2441544 98 +++++ +++ (This is with -smp 1) There seams to be no major performance difference between ide and scsi while virtio is not to be recommended at this moment. All in all the IO looks very close to native, at least with this limited tests. /Henrik Holst