On 2020.05.21 10:16 Rafael J. Wysocki wrote: ... > > The INTEL_CPUFREQ_TRANSITION_DELAY_HWP value has been guessed and it very well > may turn out to be either too high or too low for the general use, which is > one > reason why getting as much testing coverage as possible is key here. > > If you can play with different INTEL_CPUFREQ_TRANSITION_DELAY_HWP values, > please do so and let me know the conclusions. ...
Hi Rafael, Since my v7 reply the other day about results for 347 Hz work/sleep frequency periodic workflows [1], I have been testing at 73 Hertz work/sleep frequency. And am now testing this: -#define INTEL_CPUFREQ_TRANSITION_DELAY_HWP 5000 +#define INTEL_CPUFREQ_TRANSITION_DELAY_HWP 10000 Which shows promise for the schedutil governor, which no longer drives prematurely into the turbo range, consuming excessive amounts of energy as compared to passive without HWP. The ondemand governor is still very bad. The only way I have found to get it behave is to force max=min=target_pstate, in addition to the above. It will be quite some time before I have well organized feedback. In the meantime if anyone has suggestions for an optimal INTEL_CPUFREQ_TRANSITION_DELAY_HWP value, I would be grateful. Otherwise I'll attempt to find it via tests. ... Doug [1] https://marc.info/?l=linux-pm&m=159769839401767&w=2
