Re: [Qemu-devel] [PATCH v4 00/13] aio: experimental virtio-blk polling mode

[Stefan Hajnoczi]

On Mon, Dec 05, 2016 at 10:40:49AM -0600, Karl Rister wrote:
> On 12/05/2016 08:56 AM, Stefan Hajnoczi wrote:
> <snip>
> 
> > Karl: do you have time to run a bigger suite of benchmarks to identify a
> > reasonable default poll-max-ns value?  Both aio=native and aio=threads
> > are important.
> > 
> > If there is a sweet spot that improves performance without pathological
> > cases then we could even enable polling by default in QEMU.
> > 
> > Otherwise we'd just document the recommended best polling duration as a
> > starting point for users.
> > 
> 
> I have collected a baseline on the latest patches and am currently
> collecting poll-max-ns=16384.  I can certainly throw in a few more
> scenarios.  Do we want to stick with powers of 2 or some other strategy?

Excellent, thanks!  The algorithm self-tunes by doubling poll time so
there's not much advantage to looking at non pow-2 values.

Thanks,
Stefan

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