Re: [PATCH RFC 1/2] kvm: Handle undercommitted guest case in PLEhandler

[Peter Zijlstra]

On Thu, 2012-10-04 at 14:41 +0200, Avi Kivity wrote:
> 
> Again the numbers are ridiculously high for arch_local_irq_restore.
> Maybe there's a bad perf/kvm interaction when we're injecting an
> interrupt, I can't believe we're spending 84% of the time running the
> popf instruction. 

Smells like a software fallback that doesn't do NMI, hrtimer based
sampling typically hits popf where we re-enable interrupts.
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