xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

KVM: add halt_attempted_poll to VCPU stats

Browse Source 
This new statistic can help diagnosing VCPUs that, for any reason,
trigger bad behavior of halt_poll_ns autotuning.

For example, say halt_poll_ns = 480000, and wakeups are spaced exactly
like 479us, 481us, 479us, 481us. Then KVM always fails polling and wastes
10+20+40+80+160+320+480 = 1110 microseconds out of every
479+481+479+481+479+481+479 = 3359 microseconds. The VCPU then
is consuming about 30% more CPU than it would use without
polling.  This would show as an abnormally high number of
attempted polling compared to the successful polls.

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com<
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini
2015-09-15 18:27:57 +02:00
parent 8f4216c7d2
commit 62bea5bff4
12 changed files with 12 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/include/asm/kvm_host.h
View File

@@ -711,6 +711,7 @@ struct kvm_vcpu_stat {
u32 nmi_window_exits;
u32 halt_exits;
u32 halt_successful_poll;
u32 halt_attempted_poll;
u32 halt_wakeup;
u32 request_irq_exits;
u32 irq_exits;