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| author | Suraj Jitindar Singh <sjitindarsingh@gmail.com> | 2016-10-14 03:53:22 +0300 |
|---|---|---|
| committer | Paul Mackerras <paulus@ozlabs.org> | 2016-11-28 03:48:47 +0300 |
| commit | f4944613ad1ab6760589d5791488be1236c07fcc (patch) | |
| tree | 24b650324edfb6925ce490a547bf2c3843cee8df /arch/powerpc/include | |
| parent | e03f3921e597cbcc6880033e5c52fa1db524f88b (diff) | |
| download | linux-f4944613ad1ab6760589d5791488be1236c07fcc.tar.xz | |
KVM: PPC: Decrease the powerpc default halt poll max value
KVM_HALT_POLL_NS_DEFAULT is an arch specific constant which sets the
default value of the halt_poll_ns kvm module parameter which determines
the global maximum halt polling interval.
The current value for powerpc is 500000 (500us) which means that any
repetitive workload with a period of less than that can drive the cpu
usage to 100% where it may have been mostly idle without halt polling.
This presents the possibility of a large increase in power usage with
a comparatively small performance benefit.
Reduce the default to 10000 (10us) and a user can tune this themselves
to set their affinity for halt polling based on the trade off between power
and performance which they are willing to make.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc/include')
| -rw-r--r-- | arch/powerpc/include/asm/kvm_host.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index f15713ae3f34..e59b172666cd 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -48,7 +48,7 @@ #ifdef CONFIG_KVM_MMIO #define KVM_COALESCED_MMIO_PAGE_OFFSET 1 #endif -#define KVM_HALT_POLL_NS_DEFAULT 500000 +#define KVM_HALT_POLL_NS_DEFAULT 10000 /* 10 us */ /* These values are internal and can be increased later */ #define KVM_NR_IRQCHIPS 1 |