Messages in this thread | | | Date | Mon, 5 Mar 2018 12:38:03 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC/RFT][PATCH 4/7] cpuidle: menu: Split idle duration prediction from state selection |
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On Sun, Mar 04, 2018 at 11:26:24PM +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > In order to address the issue with short idle duration predictions > by the idle governor after the tick has been stopped, prepare the > menu governor code for reordering with respect to the timekeeping > code that stops the tick. > > Use the observation that menu_select() can be split into two > functions, one predicting the idle duration and one selecting the > idle state, and rework it accordingly.
I actually think this is the wrong way around.
We really should be predicting state not duration. Yes the duration thing is an intermediate value, but I don't think it makes any sense what so ever to preserve that in the predictor. The end result is the idle state, we should aim for that.
As per:
https://lkml.org/lkml/2017/7/18/615
there are definite advantages to _not_ preserving duration information beyond the state boundaries.
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