On 2019.08.08 19:16 Viresh Kumar wrote: > On 08-08-19, 09:25, Doug Smythies wrote: >> On 2019.08.07 00:06 Viresh Kumar wrote: >> Tested by: Doug Smythies <dsmyth...@telus.net> >> Thermald seems to now be working O.K. for all the governors. > > Thanks for testing Doug. > >> I do note that if one sets >> /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq >> It seems to override subsequent attempts via >> /sys/devices/system/cpu/intel_pstate/max_perf_pct. >> Myself, I find this confusing. >> >> So the question becomes which one is the "master"? > > No one is master, cpufreq takes all the requests for frequency > constraints and tries to set the value based on aggregation of all. So > for max frequency, the lowest value wins and is shown up in sysfs. > > So, everything looks okay to me.
O.K. While I understand the explanations, I still struggle with this scenario: doug@s15:~/temp$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct 50 <<< Note: 50% = 1.9 GHz in my system) doug@s15:~/temp$ grep . /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:1900000 /sys/devices/system/cpu/cpufreq/policy1/scaling_max_freq:1900000 /sys/devices/system/cpu/cpufreq/policy2/scaling_max_freq:1900000 /sys/devices/system/cpu/cpufreq/policy3/scaling_max_freq:1900000 /sys/devices/system/cpu/cpufreq/policy4/scaling_max_freq:1900000 /sys/devices/system/cpu/cpufreq/policy5/scaling_max_freq:1900000 /sys/devices/system/cpu/cpufreq/policy6/scaling_max_freq:1900000 /sys/devices/system/cpu/cpufreq/policy7/scaling_max_freq:1900000 At this point I am not certain what I'll get if I try to set max_perf_pct to 100%, nor do I know how to find out with a user command. So, I'll try it: doug@s15:~/temp$ echo 100 | sudo tee /sys/devices/system/cpu/intel_pstate/max_perf_pct 100 doug@s15:~/temp$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct 100 <<< Note: 100% = 3.8 GHz in my system) doug@s15:~/temp$ grep . /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:2200000 /sys/devices/system/cpu/cpufreq/policy1/scaling_max_freq:2200000 /sys/devices/system/cpu/cpufreq/policy2/scaling_max_freq:2200000 /sys/devices/system/cpu/cpufreq/policy3/scaling_max_freq:2200000 /sys/devices/system/cpu/cpufreq/policy4/scaling_max_freq:2200000 /sys/devices/system/cpu/cpufreq/policy5/scaling_max_freq:2200000 /sys/devices/system/cpu/cpufreq/policy6/scaling_max_freq:2200000 /sys/devices/system/cpu/cpufreq/policy7/scaling_max_freq:2200000 I guess I had set it sometime earlier, forgot, and then didn't get 3.8 Ghz as I had expected via max_perf_pct. ... Doug
