Re: [RFC PATCH v2 6/8] cpuidle: make fast idle threshold tunable

From: Rafael J. Wysocki
Date: Mon Oct 16 2017 - 20:10:57 EST


On Monday, October 16, 2017 8:00:45 AM CEST Li, Aubrey wrote:
> On 2017/10/14 8:59, Rafael J. Wysocki wrote:
> > On Saturday, September 30, 2017 9:20:32 AM CEST Aubrey Li wrote:
> >> Add a knob to make fast idle threshold tunable
> >>
> >> Signed-off-by: Aubrey Li <aubrey.li@xxxxxxxxxxxxxxx>
> >
> > I first of all am not sure about the need to add a tunable for this at all
> > in the first place.
>
> Actually I think a fixed value(10) might be good enough but not quite sure
> if there is a requirement to tune it for different scenario, for example even
> if the predicted idle interval is 100x overhead, I still want a fast path for
> a better benchmark score?

Any new tunables make the test matrix expand considerably, so it generally is
better to err on the conservative side with adding them.

Thanks,
Rafael