Re: [PATCH v1 0/5] CPUFREQ OPP's and Tegra30 support by tegra20-cpufreq driver

[Dmitry Osipenko]

On 9/11/18 11:27 AM, Marcel Ziswiler wrote:
> On Fri, 2018-09-07 at 19:59 +0300, Dmitry Osipenko wrote:
>
> - snip -
>
> > > - With "cpufreq-info -f" I could only observe like the top 3-4 OPPs
> > > while it does not to go further down even when idling. Why could
> > > that
> > > be resp. what could cause this?
> >
> > What cpufreq governor are you using?
>
> ondemand
>
> > Here is my 'cpufreq-info --stats' output from Tegra30 after a several
> > minutes of idling after boot:
> >
> > 408000:245884, 456000:445, 608000:251, 760000:151, 816000:82,
> > 912000:75, 1000000:163  (561)
> >
> > And full cpufreq-info:
> >
> > cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
> > Report errors and bugs to cpufreq@xxxxxxxxxxxxxxx, please.
> > analyzing CPU 0:
> >     driver: tegra
> >     CPUs which run at the same hardware frequency: 0 1 2 3
> >     CPUs which need to have their frequency coordinated by software: 0
> > 1 2 3
> >     maximum transition latency: 50.0 us.
> >     hardware limits: 408 MHz - 1000 MHz
> >     available frequency steps: 408 MHz, 456 MHz, 608 MHz, 760 MHz, 816
> > MHz, 912 MHz, 1000 MHz
> >     available cpufreq governors: conservative, userspace, powersave,
> > ondemand, performance, schedutil
> >     current policy: frequency should be within 408 MHz and 1000 MHz.
> >                     The governor "ondemand" may decide which speed to
> > use
> >                     within this range.
> >     current CPU frequency is 608 MHz (asserted by call to hardware).
> >     cpufreq stats: 408 MHz:99.53%, 456 MHz:0.18%, 608 MHz:0.10%, 760
> > MHz:0.06%, 816 MHz:0.03%, 912 MHz:0.03%, 1000 MHz:0.07%  (563)
> > analyzing CPU 1:
> >     driver: tegra
> >     CPUs which run at the same hardware frequency: 0 1 2 3
> >     CPUs which need to have their frequency coordinated by software: 0
> > 1 2 3
> >     maximum transition latency: 50.0 us.
> >     hardware limits: 408 MHz - 1000 MHz
> >     available frequency steps: 408 MHz, 456 MHz, 608 MHz, 760 MHz, 816
> > MHz, 912 MHz, 1000 MHz
> >     available cpufreq governors: conservative, userspace, powersave,
> > ondemand, performance, schedutil
> >     current policy: frequency should be within 408 MHz and 1000 MHz.
> >                     The governor "ondemand" may decide which speed to
> > use
> >                     within this range.
> >     current CPU frequency is 608 MHz (asserted by call to hardware).
> >     cpufreq stats: 408 MHz:99.53%, 456 MHz:0.18%, 608 MHz:0.10%, 760
> > MHz:0.06%, 816 MHz:0.03%, 912 MHz:0.03%, 1000 MHz:0.07%  (563)
> > analyzing CPU 2:
> >     driver: tegra
> >     CPUs which run at the same hardware frequency: 0 1 2 3
> >     CPUs which need to have their frequency coordinated by software: 0
> > 1 2 3
> >     maximum transition latency: 50.0 us.
> >     hardware limits: 408 MHz - 1000 MHz
> >     available frequency steps: 408 MHz, 456 MHz, 608 MHz, 760 MHz, 816
> > MHz, 912 MHz, 1000 MHz
> >     available cpufreq governors: conservative, userspace, powersave,
> > ondemand, performance, schedutil
> >     current policy: frequency should be within 408 MHz and 1000 MHz.
> >                     The governor "ondemand" may decide which speed to
> > use
> >                     within this range.
> >     current CPU frequency is 608 MHz (asserted by call to hardware).
> >     cpufreq stats: 408 MHz:99.53%, 456 MHz:0.18%, 608 MHz:0.10%, 760
> > MHz:0.06%, 816 MHz:0.03%, 912 MHz:0.03%, 1000 MHz:0.07%  (563)
> > analyzing CPU 3:
> >     driver: tegra
> >     CPUs which run at the same hardware frequency: 0 1 2 3
> >     CPUs which need to have their frequency coordinated by software: 0
> > 1 2 3
> >     maximum transition latency: 50.0 us.
> >     hardware limits: 408 MHz - 1000 MHz
> >     available frequency steps: 408 MHz, 456 MHz, 608 MHz, 760 MHz, 816
> > MHz, 912 MHz, 1000 MHz
> >     available cpufreq governors: conservative, userspace, powersave,
> > ondemand, performance, schedutil
> >     current policy: frequency should be within 408 MHz and 1000 MHz.
> >                     The governor "ondemand" may decide which speed to
> > use
> >                     within this range.
> >     current CPU frequency is 608 MHz (asserted by call to hardware).
> >     cpufreq stats: 408 MHz:99.53%, 456 MHz:0.18%, 608 MHz:0.10%, 760
> > MHz:0.06%, 816 MHz:0.03%, 912 MHz:0.03%, 1000 MHz:0.07%  (563)
> >
> >
> > > - Unfortunately "cpufreq-info --stats" currently does not seem to
> > > output anything. Would that require something special to be
> > > implemented?
> >
> > Make sure that CONFIG_CPU_FREQ_STAT is enabled in the kernels config.
>
> Yes, sorry. That was it, of course. Just wondering why that one isn't
> enabled in tegra_defconfig...

That option isn't essential for the kernel, though usually such useful and 
low-overhead features are welcome. IIRC, tegra_defconfig misses more important 
options (like namespaces) that are required by Linux distro's to work properly.

> > > Other than that you may add the following to the whole series:
> > >
> > > Tested-by: Marcel Ziswiler <marcel.ziswiler@xxxxxxxxxxx>
> >
> > Thank you very much!
>
> You are very welcome. Thank you!