diff options
| author | Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> | 2012-07-19 15:17:52 +0530 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2012-07-23 13:02:37 +0300 |
| commit | 06e48c510aa37f6e791602e6420422ea7071fe94 (patch) | |
| tree | 083e13a1a1b58d32369adc6eaa42c2a22d17d95d /include/linux/kvm_host.h | |
| 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 'include/linux/kvm_host.h')
| -rw-r--r-- | include/linux/kvm_host.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 361b36fe7ecc..74a78d09c454 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -931,6 +931,11 @@ static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val) { } +static inline bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu) +{ + return true; +} + #endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */ #endif |