Re: [RFC PATCH 0/4] Gang scheduling in CFS

From: Avi Kivity
Date: Mon Dec 19 2011 - 06:59:56 EST


On 12/19/2011 01:50 PM, Nikunj A Dadhania wrote:
> On Mon, 19 Dec 2011 13:44:02 +0200, Avi Kivity <avi@xxxxxxxxxx> wrote:
> > On 12/19/2011 01:23 PM, Ingo Molnar wrote:
> > > What's behind this huge speedup? Does ebizzy use user-space
> > > spinlocks perhaps? Could we do something on the user-space side
> > > to get a similar speedup?
> >
> > kvm tries to detect spinlocks (by trapping repeated executions of PAUSE)
> > and yield to a related vcpu. It's far from perfect however, and relies
> > on the spinlock code using PAUSE.
> >
> Avi, is this soft-PLE kind of thing?

No, hard PLE, see the calls to yield_to.

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

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