Messages in this thread | | | Date | Wed, 6 Jun 2012 07:41:28 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 0/6] x86/cpu hotplug: Wake up offline CPU via mwait or nmi |
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On Wed, Jun 06, 2012 at 10:43:43AM +0200, Peter Zijlstra wrote: > On Tue, 2012-06-05 at 15:12 -0700, Paul E. McKenney wrote: > > > What I can't see is the isolated functional, aside from the above > > > mentioned things, that's not strictly a per-cpu property, we can have a > > > group that's isolated from the rest but not from each other. > > > > I suspect that Thomas is thinking that the CPU is so idle that it no > > longer has to participate in TLB invalidation or RCU. (Thomas will > > correct me if I am confused.) But Peter, is that the level of idle > > you are thinking of? > > No, we're talking about isolated, so its very much running something.
From what I can see, if the CPU is running something, this is Thomas's "Isolated functional" state rather than his "Isolated idle" state. The isolated-idle state should not need to participate in TLB invalidation or RCU, so that the CPU never ever needs to wake up while in the isolated-idle state.
Thanx, Paul
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