[Speed] intel_pstate C0 bug on isolated CPUs with the performance governor

[Armin Rigo]

Hi Victor,

On 27 September 2016 at 15:40, Victor Stinner <victor.stinner at gmail.com> wrote:
> 2016-09-24 8:11 GMT+02:00 Armin Rigo <arigo at tunes.org>:
>> IMHO this is not a very good solution.  With the CPU running at, say,
>> a fifth of its nominal performance, you can't expect that it will
>> behave in a remotely similar way.
>
> The norminal speed is 3.4 GHz. The minimum speed is 1.6 GHz. Timings
> are just the double between nominal and minimum speed.

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

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


A bientôt,

Armin.