Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle)

From: Mike Galbraith
Date: Tue Jan 26 2016 - 12:09:06 EST

On Tue, 2016-01-26 at 10:26 -0600, Christoph Lameter wrote:
> On Tue, 26 Jan 2016, Mike Galbraith wrote:
> > > Why would the deferring cause this overhead?
> >
> > Because we schedule to idle cores aggressively, thus we may pop in and
> > out of idle at high frequency.
> Whats the point of going idle if you have things to do soon?

When a task schedules off, how do you know it'll be back at all, much
less soon?