Re: [RFC PATCH v1 00/11] Create fast idle path for short idle periods

From: Peter Zijlstra
Date: Wed Jul 12 2017 - 08:23:02 EST


On Tue, Jul 11, 2017 at 11:09:31AM -0700, Paul E. McKenney wrote:
> On Tue, Jul 11, 2017 at 06:34:22PM +0200, Peter Zijlstra wrote:
> > Also, RCU_FAST_NO_HZ will make a fairly large difference here.. Paul
> > what's the state of that thing, do we actually want that or not?
>
> If you are battery powered and don't have tight real-time latency
> constraints, you want it -- it has represent a 30-40% boost in battery
> lifetime for some low-utilization battery-powered devices. Otherwise,
> probably not.

Would it make sense to hook that off of tick_nohz_idle_enter(); in
specific the part where we actually stop the tick; instead of every
idle?