[lkml]   [2012]   [Jul]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
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:0.125 / U:6.520 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site