[Bug 206307] New: AMD Ryzen CPU frequency monitoring subsystem is insufficient

[Bug 206307] New: AMD Ryzen CPU frequency monitoring subsystem is insufficient

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=206307

            Bug ID: 206307
           Summary: AMD Ryzen CPU frequency monitoring subsystem is
                    insufficient
           Product: Power Management
           Version: 2.5
    Kernel Version: All
          Hardware: x86-64
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: high
          Priority: P1
         Component: cpufreq
          Assignee: linux-pm@vger.kernel.org
          Reporter: aros@gmx.com
        Regression: No

These are the features which are available under Windows but not possible under
Linux in any shape or form:

1) You cannot set the desired CPU frequency except for predefined values (in my
case 3600000 2800000 2200000Hz). In Windows you can set any desired frequency
between base and boost.

2) time_in_state is extremely coarse and shows neither boost, nor CPU sleep. At
least with Intel CPUs there's an additional CPU frequency MAX + 100KHz which
indicates boost. There's no such thing for AMD Ryzen CPUs.

3) Reported frequencies values in /proc/cpuinfo and
/sys/devices/system/cpu/cpufreq/policy*/cpuinfo_cur_freq are again limited to
the predefined values.

/cpu/cpufreq/policy*/scaling_cur_freq contains a lot more varied values but
again, CPU sleeping or boosting are not reported.

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[Bug 206307] AMD Ryzen CPU frequency monitoring subsystem is insufficient

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=206307

--- Comment #1 from Artem S. Tashkinov (aros@gmx.com) ---
I really don't know who to CC to this bug report, so I'd be glad if you could
CC the relevant people.

I am perfectly aware that Ryzen CPUs can change their frequency millions of
times per seconds. I hope that still allows to aggregate data and manage the
CPU the way we want (and the way it's already possible under Windows).

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[Bug 206307] AMD Ryzen CPU frequency monitoring subsystem is insufficient

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=206307

Thomas Renninger (trenn@suse.de) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |trenn@suse.de

--- Comment #2 from Thomas Renninger (trenn@suse.de) ---
This would need another cpufreq driver.
acpi_cpufreq is fixed in the amount of frequency states and the passed array is
not that big (not sure what max supported freqs with acpi_cpufreq is, it should
be fixed around 15-20).

A driver similar to intel_pstate driver is needed.
Who is going to write this one?

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[Bug 206307] AMD Ryzen CPU frequency monitoring subsystem is insufficient

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=206307

Artem S. Tashkinov (aros@gmx.com) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |CODE_FIX

--- Comment #4 from Artem S. Tashkinov (aros@gmx.com) ---
amd-pstate does that.

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