On Tue, May 10, 2016 at 12:32:27PM +0200, Paolo Bonzini wrote: > On 10/05/2016 11:40, Kevin Wolf wrote: > > > Regarding performance, I'm thinking about a guest with 8 disks (queue > > > depth 32). The worst case is when the guest submits 32 requests at once > > > but the Linux AIO event limit has already been reached. Then the disk > > > is starved until other disks' requests complete. > > > > Sounds like a valid concern. > > Oh, so you're concerned about the non-dataplane case. My suspicion is > that, with such a number of outstanding I/O, you probably have bad > performance unless you use dataplane. > > Also, aio=threads has had a 64 I/O limit for years and we've never heard > about problems with stuck I/O. But I agree that it's one area to keep > an eye on.
Good point. In that case I don't feel so bad if we merge this. Stefan
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