RE: [PATCH v7] cpufreq: intel_pstate: Implement passive mode with HWP enabled

Doug Smythies
2020-09-07T00:16:43Z

Hi Rafael,

On 2020.08.17 14:06 Doug Smythies wrote:
> On 2020.08.06 05:04 Rafael J. Wysocki wrote:
>
> > Allow intel_pstate to work in the passive mode with HWP enabled and
> > make it set the HWP minimum performance limit (HWP floor) to the
> > P-state value given by the target frequency supplied by the cpufreq
> > governor, so as to prevent the HWP algorithm and the CPU scheduler
> > from working against each other, at least when the schedutil governor
> > is in use, and update the intel_pstate documentation accordingly.
>
...
>
> powersave governor:
> acpi-cpufreq: good
> intel_cpufreq hwp: bad
> intel_cpufreq no hwp: good

It occurs to me that my expectations as to what
is meant by "powersave" might not agree with yours.

For the powersave governor, this is what we have now:

intel_cpufreq hwp == intel_pstate hwp
intel_cpufreq no hwp == acpi-cpufreq == always minimum freq
intel_pstate no hwp ~= acpi-cpufreq/ondemand

Is that your understanding/intention?

My expectation was/is:

intel_cpufreq hwp == intel_cpufreq no hwp == acpi-cpufreq == always minimum freq
intel_pstate no hwp ~= acpi-cpufreq/ondemand
intel_pstate hwp == Unique. Say, extremely course version of ondemand.

... Doug