Re: [Powertop] cpu wiggle changes userspace governor settings

Dear Powertop Team, I have noticed that powertop changes the frequency set by the userspace governor to the minimum available frequency. This is caused by abstract_cpu::wiggle that touches the {min,max}_freq. By doing so, it also narrows down the scaling_setspeed setting within the min-max-range, but it is not reset upon restoring max_freq. To illustrate what is happening behind the scenes: $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_{min,max,cur}_freq 1200000 2901000 2000000 $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_{governor,setspeed} userspace 2000000 $ echo 1200000 | sudo tee /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq 1200000 $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed 1200000 (Tested with Linux 4.4.0-21 Ubuntu) Attached is a patch that resets the setspeed value if it was set to a numeric value before the wiggle. Please note that I don't really understand what you are trying to achieve with the wiggle in the first place. It seems for instance that this doesn't do anything if max_freq == min_freq.

Best Regards, Thomas Ilsche