Re: [PATCH 0/5] KVM paravirt_ops backend (v3)

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Anthony Liguori wrote:
> Hi,
>
> This is an update to the paravirt_ops KVM backend series.  I've made a 
> number of changes and attempted to incorporate all the feedback from 
> the last review.  Some highlights:
>
> 1) Clean up the paravirt time source patch to use a more Xen-like model
> 2) Change the hypercall queueing to pass a PA on the flush hypercall
> 3) Add MMU support for release_{pt,pd} and TLB flush
> 4) Use KVM specific errno values
> 5) Switch from per_cpu to more appropriate functions
>
> As for performance, I've got a few interesting results.  kbuild with a 
> guest using 2G of memory goes from 19 minutes to 12 minutes with the 
> full series applied.  Using 512mb, the build time goes from 10.75 
> minutes to 9 minutes.  For 512mb, native is around 7 minutes so that's 
> pretty close to what Avi had seen.  The more dramatic improvement with 
> large memory guests is probably because of the increased shadow page 
> table activity due to high mem.

Ah, that explains why we were getting such different results.  My tests 
were on x86-64.

>
> virtbench shows major improvements but I'm not 100% confident yet in 
> the results as they are not very stable.  I don't yet have a benchmark 
> that shows the benefit of the CR caching so if I don't find one, I'll 
> drop that from the queue.
>

The only barrier to merging is that we're introducing yet another stable 
ABI.  Since we can turn off things that turn out not so good later, and 
expect the guest to survive, I'm not to worried, so I'm inclined to 
merge this.


-- 
error compiling committee.c: too many arguments to function


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