[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] IO performance test on the tcm-vhost scsi

From: Paolo Bonzini
Subject: Re: [Qemu-devel] IO performance test on the tcm-vhost scsi
Date: Thu, 14 Jun 2012 14:27:15 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0

Il 14/06/2012 14:07, Stefan Hajnoczi ha scritto:
> Perfect, thanks.  virtio-scsi userspace is much better than virtio-blk
> here.  That's unexpected since they both use the QEMU block layer.  If
> anything, I would have expected virtio-blk to be faster!

Yes, I would have expected something similar.  A blktrace would be
useful here because Asias measured the opposite---virtio-scsi being much
slower than virtio-blk.

> The second question is why is tcm_vhost faster than virtio-scsi
> userspace.

I would expect a difference on more high-end benchmarks (i.e. lots of
I/O to lots of disks), similar to vhost-blk.  In this simple case I
wonder how much it is due to the vagaries of the I/O scheduler, or even
statistical noise.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]