diff options
author | Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> | 2012-07-19 15:17:52 +0530 |
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committer | Avi Kivity <avi@redhat.com> | 2012-07-23 13:02:37 +0300 |
commit | 06e48c510aa37f6e791602e6420422ea7071fe94 (patch) | |
tree | 083e13a1a1b58d32369adc6eaa42c2a22d17d95d /arch | |
parent | 4c088493c8d07e4e27bad53a99dcfdc14cdf45f8 (diff) |
KVM: Choose better candidate for directed yield
Currently, on a large vcpu guests, there is a high probability of
yielding to the same vcpu who had recently done a pause-loop exit or
cpu relax intercepted. Such a yield can lead to the vcpu spinning
again and hence degrade the performance.
The patchset keeps track of the pause loop exit/cpu relax interception
and gives chance to a vcpu which:
(a) Has not done pause loop exit or cpu relax intercepted at all
(probably he is preempted lock-holder)
(b) Was skipped in last iteration because it did pause loop exit or
cpu relax intercepted, and probably has become eligible now
(next eligible lock holder)
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> # on s390x
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch')
0 files changed, 0 insertions, 0 deletions