Hi all, I would like to ask a question regarding cpu frequency scaling / cpu performance using intel_pstate with activated HWP. I think the special CPU doesn't matter. I checked it with i7-8550U and i7-8565U. Currently I am not sure if this is a bug. Thats why I am asking...
Using intel_pstate default settings (min_perf_pct=10, max_perf_pct=100, no_turbo=0) everything behaves as expected. If I change max_perf_pct and/or no_turbo i can observe that the cpu frequency doesn't increase that much compared to the default settings under load. But if I disable smt, the settings of the pstate driver does not seem to change anything. If I set no_turbo and/or max_perf_pct to a lower value than 100 I can not notice that there is a change at the cpu frequency scaling. For example: If I set min_perf_pct=max_perf_pct=5 the cpu frequency of the 4 online cpus will be above 4 GHz in case of smt is disabled. If smt is enabled the cpu frequency of the 8 cpus is 400 MHz. The same occurred if I disable turbo by setting no_turbo to 1. If smt is disbaled the frequency will be above 4 GHz in load situations. If smt is enabled the cpu frequency is 1,80 GHz. If I use intel_pstate with disabled HWP it behaves the same if smt is enabled or disabled. So, it makes no difference if smt is enabled or disabled . The cpu frequency will adapt exactly to the configured settings. So, is this intended that HWP does not consider the pstate settings if smt is disabled? Thank you & best regards, Dennis
