RE: [intel-pstate driver regression] processor frequency very high even if in idle

["Doug Smythies" <dsmythies@telus.net>]

On 2016.03.31 02:24 Jörg Otte wrote:

> jojo@fichte:/sys/devices/system/cpu/cpufreq/policy0$ cat scaling_governor
> powersave
> 
> turbostat -i 1 --msr=0x199
> CPUID(7): No-SGX
>     CPU Avg_MHz   Busy% Bzy_MHz TSC_MHz   MSR 0x199
>       -      45    1.74    2590    2496  0x00000000
>       0      45    1.76    2565    2498  0x00000a00
>       1      72    2.84    2548    2496  0x00000800
>       2      30    1.11    2661    2496  0x00001a00
>       3      33    1.23    2661    2495  0x00001a00
>     CPU Avg_MHz   Busy% Bzy_MHz TSC_MHz   MSR 0x199
>       -       9    0.35    2525    2495  0x00000000
>       0       1    0.04    2735    2495  0x00000800
>       1       1    0.05    2501    2495  0x00000800
>       2      17    0.65    2540    2495  0x00001a00
>       3      16    0.64    2501    2495  0x00001a00
>     CPU Avg_MHz   Busy% Bzy_MHz TSC_MHz   MSR 0x199
>       -      11    0.43    2523    2495  0x00000000
>       0       3    0.11    2631    2495  0x00000c00
>       1       7    0.27    2524    2495  0x00000800
>       2      18    0.72    2527    2495  0x00001a00
>       3      15    0.61    2501    2495  0x00001a00

Very Interesting.

I would still like to get a trace sample to post process.
Copied from a previous e-mail:

On an otherwise idle system, do:

# perf record -a --event=power:pstate_sample sleep 300

If pressed for time, your sleep time can be less than 5 minutes,
but try to get at least 100 seconds.

The resulting perf.data file will be too big to include as an
on-list attachment, but send it (or them) to me off-list for
post processing, and I'll report back.

... Doug