Re: [PATCH v2 2/3] KVM: dynamic halt_poll_ns adjustment

From: Wanpeng Li
Date: Wed Aug 26 2015 - 05:13:01 EST

On 8/26/15 1:19 AM, David Matlack wrote:
Thanks for writing v2, Wanpeng.

On Mon, Aug 24, 2015 at 11:35 PM, Wanpeng Li <> wrote:
There is a downside of halt_poll_ns since poll is still happen for idle
VCPU which can waste cpu usage. This patch adds the ability to adjust
halt_poll_ns dynamically.
What testing have you done with these patches? Do you know if this removes
the overhead of polling in idle VCPUs? Do we lose any of the performance
from always polling?

There is 0.8% kernel compile performance improvement(10 iterations) on host w/ 800 idle vCPUs. Btw, I handle all your comments in v3. Many thanks for your review, David! :-)

Wanpeng Li
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