lkml.org 
[lkml]   [2012]   [Jul]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH RFC V3 0/3] kvm: Improving directed yield in PLE handler
    On 07/13/2012 12:47 AM, Raghavendra K T wrote:
    > Currently Pause Loop Exit (PLE) handler is doing directed yield to a
    > random vcpu on pl-exit. We already have filtering while choosing
    > the candidate to yield_to. This change adds more checks while choosing
    > a candidate to yield_to.
    >
    > On a large vcpu guests, there is a high probability of
    > yielding to the same vcpu who had recently done a pause-loop exit.
    > Such a yield can lead to the vcpu spinning again.
    >
    > The patchset keeps track of the pause loop exit and gives chance to a
    > vcpu which has:
    >
    > (a) Not done pause loop exit at all (probably he is preempted lock-holder)
    >
    > (b) vcpu skipped in last iteration because it did pause loop exit, and
    > probably has become eligible now (next eligible lock holder)
    >
    > This concept also helps in cpu relax interception cases which use same handler.

    The patches are tested on x86 only since I don't have access to s390
    machine. Please let me know if changes are ok on s390.



    \
     
     \ /
      Last update: 2012-07-12 22:21    [W:0.024 / U:29.436 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site