Re: [PATCH RFC 0/2] kvm: Improving directed yield in PLE handler

From: Avi Kivity
Date: Thu Jul 12 2012 - 08:31:53 EST


On 07/12/2012 11:25 AM, Raghavendra K T wrote:
>>
>> The problem occurs even with no overcommit at all. One vcpu is in a
>> legitimately long pause loop. All those exits accomplish nothing, since
>> all vcpus are scheduled. Better to let it spin in guest mode.
>>
>
> I agree. One idea is we can have a scan_window to limit the scan of all
> n vcpus each time we enter vcpu_spin, to say 2*log n initially;

Not sure I agree. The subset that we scan is in no way special, there's
no reason to suppose it would be effective.

We can make the loop exit time scale with the number of vcpus to account
for the greater effort needed to wake a vcpu.


--
error compiling committee.c: too many arguments to function


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