On Mon, Nov 21, 2016 at 02:37:27PM +0000, Juri Lelli wrote: > On 21/11/16 15:17, Peter Zijlstra wrote:
> > Not sure I follow. So by limiting decay to the task value, the moment we > > add it back to the accumulated signal (wakeup), the accumulated signal > > jumps up quickly and ramp-up is achieved. > > > > This is true, but it seems that this potentially spiky behaviour > (which in general depends on tasks composition and periodicity) might > affect power savings (as in you don't generally want to switch between > high and low freqs too often). So that's why I was just thinking that > some sort of smoothing applied to the signal schedutil uses might help. Hurm.. so during LPC it was said that fast ramp-up was desired. Note that we'll not ramp down this fast, the accumulated signal will decay slowly as per blocked-load PELT rules. So only ramp-up is spiky, but that is what was desired AFAIU.
