Re: [RFCv7 PATCH 03/10] sched: scheduler-driven cpu frequency selection

[Peter Zijlstra]

On Fri, Feb 26, 2016 at 08:17:46PM -0800, Steve Muckle wrote:
> > But then it would only make a difference if cpufreq_update_util() was not
> > used at all (ie. no callbacks installed for any policies by anyone).  The
> > only reason why it may matter is that the total number of systems using
> > the performance governor is quite large AFAICS and they would benefit from
> > that.
> 
> I'd think that's a benefit worth preserving, but I guess that's Peter
> and Ingo's call.

Probably worth it, most of this is on rather fast paths.

See commit 1cde2930e154 ("sched/preempt: Add static_key() to
preempt_notifiers") for example.