On 21/11/16 11:19, Peter Zijlstra wrote: > On Mon, Nov 21, 2016 at 03:38:05PM +0530, Viresh Kumar wrote: > > On 17-11-16, 10:48, Viresh Kumar wrote:
[...] > > > > (Background story for others from my discussion with Rafael on IRC: Rafael > > proposed that instead of this patch we can add down_rate_limit_delta_us (>0 > > =) > > which can be added to rate_limit_us (rate limit while increasing freq) to > > find > > the rate limit to be used in the downward direction. And I raised the point > > that it looks much neater to have separate up and down rate_limit_us. I also > > said that people may have a valid case where they want to keep > > down_rate_limit > > lower than up_rate_limit and Rafael wasn't fully sure of any such cases). > > > > Urgh... > > > So no tunables and rate limits here at all please. > > During LPC we discussed the rampup and decay issues and decided that we > should very much first address them by playing with the PELT stuff. > Morton was going to play with capping the decay on the util signal. This > should greatly improve the ramp-up scenario and cure some other wobbles. > > The decay can be set by changing the over-all pelt decay, if so desired. > Do you mean we might want to change the decay (make it different from ramp-up) once for all, or maybe we make it tunable so that we can address different power/perf requirements? > Also, there was the idea of; once the above ideas have all been > explored; tying the freq ram rate to the power curve. > Yep. That's an interesting one to look at, but it might require some time. > So NAK on everything tunable here.
