From: Paolo Bonzini <pbonzini@redhat.com>
To: Liu Yuan <namei.unix@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
Stefan Hajnoczi <stefanha@gmail.com>,
qemu-devel@nongnu.org,
MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Subject: Re: [Qemu-devel] [PATCH] sheepdog: implement direct write semantics
Date: Wed, 09 Jan 2013 12:10:31 +0100 [thread overview]
Message-ID: <50ED5027.8090008@redhat.com> (raw)
In-Reply-To: <50ED4D39.9000900@gmail.com>
Il 09/01/2013 11:58, Liu Yuan ha scritto:
> 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?
"hdparm" is specific for IDE devices. sysfs is supported by SCSI
(including IDE with libata, and virtio-scsi) and virtio-blk.
You can use this for SCSI:
echo 'write back' > /sys/block/sda/device/scsi_disk/*/cache_type
and a similar command for virtio-blk.
Paolo
> 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
>
>
next prev parent reply other threads:[~2013-01-09 11:10 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-19 18:29 [Qemu-devel] [PATCH] sheepdog: implement direct write semantics Liu Yuan
2012-12-25 7:47 ` MORITA Kazutaka
2012-12-25 8:26 ` Liu Yuan
2012-12-25 8:45 ` Liu Yuan
2013-01-03 13:43 ` Liu Yuan
2013-01-04 16:38 ` Stefan Hajnoczi
2013-01-05 4:40 ` Liu Yuan
2013-01-05 5:29 ` Liu Yuan
2013-01-05 7:56 ` Liu Yuan
2013-01-07 12:31 ` Stefan Hajnoczi
2013-01-08 5:28 ` Liu Yuan
2013-01-07 13:23 ` Kevin Wolf
2013-01-08 5:42 ` Liu Yuan
2013-01-08 9:40 ` Stefan Hajnoczi
2013-01-08 9:45 ` Liu Yuan
2013-01-08 10:00 ` Kevin Wolf
2013-01-08 10:39 ` Liu Yuan
2013-01-08 10:51 ` Kevin Wolf
2013-01-08 11:08 ` Liu Yuan
2013-01-08 11:19 ` Kevin Wolf
2013-01-08 11:35 ` Liu Yuan
2013-01-08 12:12 ` Kevin Wolf
2013-01-08 13:18 ` Liu Yuan
2013-01-08 13:23 ` Liu Yuan
2013-01-09 10:25 ` Paolo Bonzini
2013-01-09 10:36 ` Liu Yuan
2013-01-09 10:40 ` Paolo Bonzini
2013-01-09 10:46 ` Liu Yuan
2013-01-09 10:58 ` Liu Yuan
2013-01-09 11:10 ` Paolo Bonzini [this message]
2013-01-09 12:07 ` Liu Yuan
2013-01-09 12:10 ` Liu Yuan
2013-01-09 12:16 ` Liu Yuan
2013-01-09 12:42 ` Kevin Wolf
2013-01-09 13:04 ` Liu Yuan
2013-01-09 15:10 ` Paolo Bonzini
2013-01-10 5:38 ` Liu Yuan
2013-01-11 7:52 ` MORITA Kazutaka
2013-01-11 8:07 ` Liu Yuan
2013-01-11 9:00 ` Paolo Bonzini
2013-01-11 9:04 ` Liu Yuan
2013-01-11 9:34 ` Paolo Bonzini
2013-01-11 9:38 ` Liu Yuan
2013-01-11 9:40 ` Paolo Bonzini
2013-01-11 9:32 ` Kevin Wolf
2013-01-10 15:25 ` Jamie Lokier
2013-01-10 15:31 ` Paolo Bonzini
2013-01-10 17:22 ` Jamie Lokier
2013-01-09 11:10 ` Kevin Wolf
2013-01-09 10:23 ` Paolo Bonzini
2013-01-10 15:12 ` Jamie Lokier
2013-01-10 15:21 ` Kevin Wolf
2013-01-10 8:03 ` [Qemu-devel] [PATCH v2] " Liu Yuan
2013-01-10 9:04 ` Stefan Hajnoczi
2013-01-11 7:35 ` MORITA Kazutaka
2013-01-11 9:23 ` Kevin Wolf
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