Messages in this thread |  | | | Date | Tue, 14 Dec 2010 14:55:35 +0530 | | From | Balbir Singh <> | | Subject | Re: [RFC PATCH 0/3] directed yield for Pause Loop Exiting |
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* Rik van Riel <riel@redhat.com> [2010-12-13 12:02:51]:
> On 12/11/2010 08:57 AM, Balbir Singh wrote: > > >If the vpcu holding the lock runs more and capped, the timeslice > >transfer is a heuristic that will not help. > > That indicates you really need the cap to be per guest, and > not per VCPU. >
Yes, I personally think so too, but I suspect there needs to be a larger agreement on the semantics. The VCPU semantics in terms of power apply to each VCPU as opposed to the entire system (per guest).
> Having one VCPU spin on a lock (and achieve nothing), because > the other one cannot give up the lock due to hitting its CPU > cap could lead to showstoppingly bad performance.
Yes, that seems right!
-- Three Cheers, Balbir
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