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Re: [vfio-users] Speed tips requested



On Sun, 2017-03-26 at 09:17 -0400, Joshua Lee wrote:
> On Sun, Mar 26, 2017 at 6:33 AM, Patrick O'Callaghan <poc usb ve> wrote:
> 
> > On Sun, 2017-03-26 at 10:58 +0100, Bronek Kozicki wrote:
> > > Assuming you use libvirt, make sure to use vCPU pinning. For disk
> > 
> > access, try cache='writeback' io='threads'. If you switch to scsio-vfio,
> > this will give you the ability to define queue length which might
> > additionally improve IO. Also, try QCOW2 format for guest disk, it might
> > enable some additional optimizations. However given you host seem to have
> > little spare capacity, YMMV
> > 
> > Thanks. I'm already using CPU pinning as I said. The disk options are
> > both set to "hypervisor default" so I'll try changing them. I'd
> > configured the guest disk as 'raw' assuming that would be faster than
> > QCOW2 but I'll look into it.
> > 
> > 
> 
> Here's a link with some benchmarks. If configured correctly, QCOW2 can be
> more efficient than native i/o:
> 
> http://jrs-s.net/2013/05/17/kvm-io-benchmarking/

Thanks, that's very useful.

poc


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