Messages in this thread | | | From | Anthony Liguori <> | Subject | Re: [PATCH RESEND 5/5] vhost-blk: Add vhost-blk support | Date | Fri, 20 Jul 2012 15:56:19 -0500 |
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"Michael S. Tsirkin" <mst@redhat.com> writes:
> On Thu, Jul 19, 2012 at 08:05:42AM -0500, Anthony Liguori wrote: >> Of course, the million dollar question is why would using AIO in the >> kernel be faster than using AIO in userspace? > > Actually for me a more important question is how does it compare > with virtio-blk dataplane?
I'm not even asking for a benchmark comparision. It's the same API being called from a kernel thread vs. a userspace thread. Why would there be a 60% performance difference between the two? That doesn't make any sense.
There's got to be a better justification for putting this in the kernel than just that we can.
I completely understand why Christoph's suggestion of submitting BIOs directly would be faster. There's no way to do that in userspace.
Regards,
Anthony Liguori
> > -- > MST
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