Messages in this thread | | | Date | Mon, 09 Jul 2012 18:28:03 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH RFC 0/2] kvm: Improving directed yield in PLE handler |
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On 07/09/2012 02:20 AM, Raghavendra K T wrote: > Currently Pause Looop Exit (PLE) handler is doing directed yield to a > random VCPU on PL exit. Though we already have filtering while choosing > the candidate to yield_to, we can do better. > > Problem is, for large vcpu guests, we have more probability of yielding > to a bad vcpu. We are not able to prevent directed yield to same guy who > has done PL exit recently, who perhaps spins again and wastes CPU. > > Fix that by keeping track of who has done PL exit. So The Algorithm in series > give chance to a VCPU which has: > > (a) Not done PLE exit at all (probably he is preempted lock-holder) > > (b) VCPU skipped in last iteration because it did PL exit, and probably > has become eligible now (next eligible lock holder) > > Future enhancemnets:
Your patch series looks good to me. Simple changes with a significant result.
However, the simple heuristic could use some comments :)
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