2016-09-29 17:11 GMT+02:00 Armin Rigo arigo@tunes.org:

On my laptop, the speed ranges between 500MHz and 2300MHz.

Oh I see, on this computer the difference can be up to 5x slower!

...

• (Use NOHZ_FULL but) Force frequency to the maximum
• Don't use NOHZ_FULL

I think we should force the frequency to a single number which is the maximum that can be reasonably sustained

In my experience, the CPU is fine when running at the nominal speed. I'm talking about the value displayed in the CPU model in /cpu/cpuinfo (2.9 GHz):

$ grep 'model name' /proc/cpuinfo model name : Intel(R) Core(TM) i7-3520M CPU @ 2.90GHz

(I mean, not the overclocked speed done by some CPUs for short amounts of time).

This is the Turbo Mode. It can be disabled in the BIOS or by writing 1 into /sys/devices/system/cpu/intel_pstate/no_turbo

By the way, the most reliable tool that I found to read the CPU frequency is turbostat. I used APERF and MPERF counters to compute the "Busy MHz". You may also try "cpupower monitor" which is similar.

Victor