path: root/arch/x86/kvm/pmu.c
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authorRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>2012-07-19 15:17:52 +0530
committerAvi Kivity <avi@redhat.com>2012-07-23 13:02:37 +0300
commit06e48c510aa37f6e791602e6420422ea7071fe94 (patch)
tree083e13a1a1b58d32369adc6eaa42c2a22d17d95d /arch/x86/kvm/pmu.c
parent4c088493c8d07e4e27bad53a99dcfdc14cdf45f8 (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/x86/kvm/pmu.c')
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