[vfio-users] Speed tips requested

[Joshua Lee]

On Sun, Mar 26, 2017 at 6:33 AM, Patrick O'Callaghan <poc at 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/
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