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Re: [Qemu-devel] virtio-blk multiqueue support in qemu.
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] virtio-blk multiqueue support in qemu. |
Date: |
Thu, 9 Jul 2015 16:29:30 +0300 |
On Thu, Jul 09, 2015 at 02:22:48PM +0100, Stefan Hajnoczi wrote:
> On Wed, Jul 08, 2015 at 05:37:12PM +0300, Michael S. Tsirkin wrote:
> > On Thu, Jul 02, 2015 at 09:21:21AM +0800, Fam Zheng wrote:
> > > On Wed, 07/01 22:45, Naredula Janardhana Reddy wrote:
> > > > HI,
> > > > I am trying to improve the throughput of virtio-blk for my kernel
> > > > (
> > > > https://github.com/naredula-jana/Jiny-Kernel ) to make use of the
> > > > multi-core using multi-queue. But I found the latest qemu does not
> > > > support
> > > > multiqueue for virtio-blk, The feature flag does not return multi-queue
> > > > support. Do we have any patches to the qemu for enabling multi-queue for
> > > > virtio-blk similar to that of virtio-net. Can someone help some
> > > > pointers
> > > > related to this..
> > >
> > > There was a series last year adding support for multi-queue but wan't
> > > merged to
> > > the code base:
> > >
> > > http://comments.gmane.org/gmane.comp.emulators.qemu/289126
> > >
> > > Fam
> >
> > Looks like it was mostly about the missing GPL license on some files.
> > Or did I miss some bigger issues?
>
> I reviewed the series again. The most important part:
>
> It was not a true multiqueue implementation - all the virtqueues are
> handled from a single thread in QEMU. The reason for this is that
> QEMU's block layer isn't threadsafe so a lot of work is necessary to
> support true multiqueue.
>
> Also, the performance numbers quoted cannot be attributed to multiqueue
> due to the number of additional changes the series made. In the
> meantime, some of these additional changes have been merged as separate
> series.
>
> On the positive side, we do need something similar to the last 3 patches
> to expose multiqueue to the guest. But it will require much more work
> in QEMU to achieve true multiqueue.
>
> Stefan
Might this be useful as an intermediate step, e.g. for testing
guest code?
--
MST
- [Qemu-devel] virtio-blk multiqueue support in qemu., Naredula Janardhana Reddy, 2015/07/01
- Re: [Qemu-devel] virtio-blk multiqueue support in qemu., Fam Zheng, 2015/07/01
- Re: [Qemu-devel] virtio-blk multiqueue support in qemu., Michael S. Tsirkin, 2015/07/08
- Re: [Qemu-devel] virtio-blk multiqueue support in qemu., Stefan Hajnoczi, 2015/07/09
- Message not available
- Re: [Qemu-devel] virtio-blk multiqueue support in qemu.,
Michael S. Tsirkin <=
- Re: [Qemu-devel] virtio-blk multiqueue support in qemu., Naredula Janardhana Reddy, 2015/07/10
- Re: [Qemu-devel] virtio-blk multiqueue support in qemu., Stefan Hajnoczi, 2015/07/13
- Re: [Qemu-devel] virtio-blk multiqueue support in qemu., Paolo Bonzini, 2015/07/13
- Re: [Qemu-devel] virtio-blk multiqueue support in qemu., Michael S. Tsirkin, 2015/07/13
- Re: [Qemu-devel] virtio-blk multiqueue support in qemu., Paolo Bonzini, 2015/07/13
- Re: [Qemu-devel] virtio-blk multiqueue support in qemu., Michael S. Tsirkin, 2015/07/13