Re: [RFC 00/10] KVM: Add TMEM host/guest support

Avi Kivity
2012-06-12T11:09:58Z

On 06/11/2012 10:25 PM, Sasha Levin wrote:
> On Mon, 2012-06-11 at 20:06 +0300, Avi Kivity wrote:
>> Sorry, no, first demonstrate no performance regressions, then we can
>> talk about performance improvements.
>
> No performance regressions? For caching? How would that work?

A small degradation might be acceptable. 2X cpu consumption is not.

IMO "using host memory" is the problem, because it involves copies and
hypercalls. Try giving the memory to the guest, either through the
balloon or through a pci device that exposes memory that can be
withdrawn. That will make everything *much* faster.

>
> Or even if you meant just the kvm-tmem interface overhead, I don't see
> how that would work.
>

I meant the overall overhead, as seen by users.

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