From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:33056) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TstMI-0008Ls-Hk for qemu-devel@nongnu.org; Wed, 09 Jan 2013 05:58:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TstMH-0003xN-AO for qemu-devel@nongnu.org; Wed, 09 Jan 2013 05:58:10 -0500 Received: from mail-da0-f41.google.com ([209.85.210.41]:51613) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TstMH-0003xH-2q for qemu-devel@nongnu.org; Wed, 09 Jan 2013 05:58:09 -0500 Received: by mail-da0-f41.google.com with SMTP id e20so693146dak.0 for ; Wed, 09 Jan 2013 02:58:08 -0800 (PST) Message-ID: <50ED4D39.9000900@gmail.com> Date: Wed, 09 Jan 2013 18:58:01 +0800 From: Liu Yuan MIME-Version: 1.0 References: <1355941771-3418-1-git-send-email-namei.unix@gmail.com> <87k3s6shdv.wl%morita.kazutaka@lab.ntt.co.jp> <50D967C3.7020109@gmail.com> <50E58B19.2050701@gmail.com> <20130104163830.GF6310@stefanha-thinkpad.hitronhub.home> <50E7AEC4.5080309@gmail.com> <50E7BA41.3020307@gmail.com> <50E7DC9B.4080309@gmail.com> <50EACC61.2020603@redhat.com> <50EBB1CB.9030608@gmail.com> <20130108094025.GE2557@stefanha-thinkpad.redhat.com> <50EBEAD2.6070608@gmail.com> <50EBEE42.7010407@redhat.com> <50EBF755.3050607@gmail.com> <50EBFA3F.8030808@redhat.com> <50EBFE20.9010100@gmail.com> <50EC00CE.80205@redhat.com> <50EC0493.8030701@gmail.com> <50EC0D41.4070200@redhat.com> <50EC1C9A.5040006@gmail.com> <50ED45A8.5020706@redhat.com> <50ED4829.1070302@gmail.com> <50ED4933.3040001@redhat.com> <50ED4A90.2080808@gmail.com> In-Reply-To: <50ED4A90.2080808@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] sheepdog: implement direct write semantics List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Kevin Wolf , Stefan Hajnoczi , qemu-devel@nongnu.org, MORITA Kazutaka On 01/09/2013 06:46 PM, Liu Yuan wrote: > I'll collect some numbers on it. Well, when I use hdparm -W 0 /dev/vdx to choose the writethrough cache in the Guest (virtio disk), it says: test@vm1:~$ sudo hdparm -W 0 /dev/vdb /dev/vdb: setting drive write-caching to 0 (off) HDIO_DRIVE_CMD(identify) failed: Inappropriate ioctl for device HDIO_DRIVE_CMD(flushcache) failed: Inappropriate ioctl for device HDIO_DRIVE_CMD(setcache) failed: Inappropriate ioctl for device HDIO_DRIVE_CMD(identify) failed: Inappropriate ioctl for device HDIO_DRIVE_CMD(flushcache) failed: Inappropriate ioctl for device HDIO_DRIVE_CMD(identify) failed: Inappropriate ioctl for device Do I need extra flags to enable WCE? Both Guest and Host kernel is 3.7 and I start QEMU by following command: $ qemu-system-x86_64 --enable-kvm -drive file=~/images/test1,if=virtio,cache=writeback -smp 2 -cpu host -m 1024 -drive file=sheepdog:test,if=virtio,cache=writeback Thanks, Yuan