RE: [PATCH 1/2] cpufreq: Introduce target min and max frequency hints

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

Hi Rafael:

Thank you for this patch set.

I can not get the patch to apply.
I was trying on top on 5.10-rc2, and have been unable to determine
what other patches might need to be applied first.

On 2020.11.05 10:24 Rafael J. Wysocki wrote:

...

> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>  drivers/cpufreq/cpufreq.c             |    3 +++
>  drivers/cpufreq/cpufreq_performance.c |    4 ++++
>  drivers/cpufreq/cpufreq_powersave.c   |    4 ++++
>  include/linux/cpufreq.h               |   16 ++++++++++++++++

I do not understand why this part says to look for 16
differences, but I can only find 2.

>  4 files changed, 27 insertions(+)
> 
> Index: linux-pm/include/linux/cpufreq.h
> ===================================================================
> --- linux-pm.orig/include/linux/cpufreq.h
> +++ linux-pm/include/linux/cpufreq.h
> @@ -63,6 +63,8 @@ struct cpufreq_policy {
> 
>  	unsigned int		min;    /* in kHz */
>  	unsigned int		max;    /* in kHz */
> +	unsigned int		target_min; /* in kHz */
> +	unsigned int		target_max; /* in kHz */
>  	unsigned int		cur;    /* in kHz, only needed if cpufreq
>  					 * governors are used */
>  	unsigned int		suspend_freq; /* freq to set during suspend */
> Index: linux-pm/drivers/cpufreq/cpufreq.c

...

Anyway, I edited the patch, deleting the include/linux/cpufreq.h part,
then it applied, as did patch 2 of 2.
I edited include/linux/cpufreq.h manually.

Issues with the powersave governor reported in [1] and [2]
are fixed. Relevant part quoted and updated below:

> In early September Doug wrote:
>> powersave governor:
>> acpi-cpufreq: good
>> intel_cpufreq hwp: bad

Now good, with this patch set.

>> intel_cpufreq no hwp: good

...

> 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

...

> My expectation was/is:
> 
> intel_cpufreq hwp == intel_cpufreq no hwp == acpi-cpufreq == always minimum freq

And this is what we now have, with this patch set.

> intel_pstate no hwp ~= acpi-cpufreq/ondemand
> intel_pstate hwp == Unique. Say, extremely course version of ondemand.

[1] https://marc.info/?l=linux-pm&m=159769839401767&w=2
[2] https://marc.info/?l=linux-pm&m=159943780220923&w=2

... Doug