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Date: Thu, 26 Nov 2015 10:53:24 +0800
From: Fam Zheng <famz@redhat.com>
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Subject: Re: [Qemu-devel] poor virtio-scsi performance (fio testing)
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To: Vasiliy Tolstov <v.tolstov@selfip.ru>
Cc: Stefan Hajnoczi <stefanha@gmail.com>, qemu-devel <qemu-devel@nongnu.org>

On Wed, 11/25 13:10, Vasiliy Tolstov wrote:
> 2015-11-25 12:35 GMT+03:00 Stefan Hajnoczi <stefanha@gmail.com>:
> > You can get better aio=native performance with qemu.git/master.  Please
> > see commit fc73548e444ae3239f6cef44a5200b5d2c3e85d1 ("virtio-blk: use
> > blk_io_plug/unplug for Linux AIO batching").
> 
> 
> Thanks Stefan! Does this patch only for virtio-blk or it can increase
> iops for virtio-scsi ?
> 

The patch was for virtio-blk but qemu.git/master also has another patch for
virtio-scsi (5170f40 virtio-scsi: Call bdrv_io_plug/bdrv_io_unplug in cmd
request handling).

On the other hand it would be helpful to compare the difference between
virtio-blk and virtio-scsi in your environment. Could you do that?

Fam