Re: [PATCH 3/3] virtio-blk: Add bio-based IO path for virtio-blk

[Asias He]

On 07/04/2012 10:40 AM, Rusty Russell wrote:
> On Tue, 03 Jul 2012 08:39:39 +0800, Asias He <asias@xxxxxxxxxx> wrote:
> > On 07/02/2012 02:41 PM, Rusty Russell wrote:
> > > Sure, our guest merging might save us 100x as many exits as no merging.
> > > But since we're not doing many requests, does it matter?
> >
> > We can still have many requests with slow devices. The number of
> > requests depends on the workload in guest. E.g. 512 IO threads in guest
> > keeping doing IO.
>
> You can have many requests outstanding.  But if the device is slow, the
> rate of requests being serviced must be low.

Yes.

> Am I misunderstanding something?  I thought if you could have a high
> rate of requests, it's not a slow device.

Sure.

--
Asias


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