Re: [RFC PATCH 0/3] directed yield for Pause Loop Exiting

From: Rik van Riel
Date: Mon Dec 13 2010 - 12:03:21 EST


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.

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.

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