TomTheBear
commented
3 years ago LIKWID never stores the state of CPU and Uncore frequencies that's why there isn't anything like return to initial settings. Moreover, likwid-setFrequencies refuses to execute some settings: If turbo mode is disabled, the maximal usable frequency is the base frequency. So if you want to set a frequency higher than base with turbo disabled, likwid-setFrequencies will refuse to do it (and should print a message about it which does not seem to work in all cases). Moreover, if turbo is enabled, it does not make much sense to select a frequency below base frequency because the turbo will overwrite it and the frequency is not stable.
So, you started with a system in turbo mode (turbo on, 1.0-3.7 GHz). Then you deactivated turbo mode, so the range of usable frequencies reduced to 1.0-<base_freq> (probably 2.3 GHz). That's why -x 1.0 -y 3.7 didn't work, the 3.7 GHz is out of range. The -reset -ureset didn't change anything because your CPU frequencies were already set to the reset values before. What you want is -t 1 -reset. You havn't changed anything for the Uncore, so using -ureset wasn't needed. Since turbo was still off in your last attempt to pin to 3.0 GHz (-f 3.0), it got ignored as well because it's above base frequency.
So, if you want to get the initial settings back, you can tell it to do so explicitly -t 1 -x 1.0 -y 3.7 or use -t 1 -reset.
The documentation for -reset contains basically all that info:
Change CPU frequencies to its minimal and maximal frequencies. If not specified, the turbo is deactivated and the maximum non-turbo frequency selected. The turbo reset setting can be set with -t <0|1>. The governor is switched back to the last on the list of available governors (-m) or to the one specified (-g
).
So for your system:
-reset: Turn turbo off and set frequencies to 1.0-2.3 GHz-t 1 reset: Turn turbo on and set frequencies to 1.0-3.7 GHz
Note: Some frequencies are not available in a machine-readable form, like min/max Uncore frequencies. Therefore, in case of -ureset, it uses the CPU frequencies as basis. That's why your -ureset changed the min Uncore frequency from 1.2 GHz to 1.0 GHz and the max Uncore frequency from 2.4 GHz to 3.7 GHz. The Uncore ignores settings outside of range, so even if you specify 3.7 GHz as maximum, it runs only with 2.4 GHz (observable with likwid-perfctr).
pramodk
What are you searching for
I am trying to understand
likwid-setFrequenciesand reading the documentation from https://github.com/RRZE-HPC/likwid/wiki/likwid-setFrequencies.This is what I tried from the beginning:
which worked fine.
min/cur/max 1.0/2.999938/3.7 GHz Turbo 1. So I tried following but that didn't check :Why am I not able to change max frequency again?
I see that Uncore is now reset to 3.7 instead of original
min/max 1.2/2.4 GHz. But I don't see any change in freq for HWThread.-f:Question : I want to reset changes I made and want to return to initial settings. Assuming there is no root access (i.e. without
cpupower), how to can I restore original min/cur/max frequencies using likwid commands?If I have missed any obvious part of documentation then let me know.
Thank you in advance!