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    SubjectRe: [PATCH RFC 0/2] kvm: Improving directed yield in PLE handler
    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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