RE: [PATCH 7/7] Documentation: cpufreq: amd-pstate: introduce the new cpu boost control method

[Yuan, Perry]

[AMD Official Use Only - General]

> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@xxxxxxx>
> Sent: Friday, January 26, 2024 11:47 PM
> To: Yuan, Perry <Perry.Yuan@xxxxxxx>; rafael.j.wysocki@xxxxxxxxx;
> viresh.kumar@xxxxxxxxxx; Huang, Ray <Ray.Huang@xxxxxxx>; Shenoy,
> Gautham Ranjal <gautham.shenoy@xxxxxxx>; Petkov, Borislav
> <Borislav.Petkov@xxxxxxx>
> Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Huang, Shimmer
> <Shimmer.Huang@xxxxxxx>; Du, Xiaojian <Xiaojian.Du@xxxxxxx>; Meng,
> Li (Jassmine) <Li.Meng@xxxxxxx>; linux-pm@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH 7/7] Documentation: cpufreq: amd-pstate: introduce the
> new cpu boost control method
>
> On 1/26/2024 02:08, Perry Yuan wrote:
> > From: Perry Yuan <Perry.Yuan@xxxxxxx>
> >
> > Introduce AMD CPU frequency boosting control sysfs entry which userd
> > for switching boost on and boost off.
>
> Typo in this sentence.

Fixed by V2.

>
> >
> > If core performance boost is disabled while a core is in a boosted
> > P-state, the core automatically transitions to the highest performance
> > non-boosted P-state The highest perf and frequency will be limited by the
> setting value.
> >
> > Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
> > ---
> >   Documentation/admin-guide/pm/amd-pstate.rst | 11 +++++++++++
> >   1 file changed, 11 insertions(+)
> >
> > diff --git a/Documentation/admin-guide/pm/amd-pstate.rst
> > b/Documentation/admin-guide/pm/amd-pstate.rst
> > index 1cf40f69278c..d72dc407c4db 100644
> > --- a/Documentation/admin-guide/pm/amd-pstate.rst
> > +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> > @@ -385,6 +385,17 @@ control its functionality at the system level.  They
> are located in the
> >           to the operation mode represented by that string - or to be
> >           unregistered in the "disable" case.
> >
> > +``cpb_boost``
> > +        Specifies whether core performance boost is requested to be enabled
> or disabled
> > +        If core performance boost is disabled while a core is in a boosted P-
> state, the
> > +        core automatically transitions to the highest performance non-boosted
> P-state.
> > +        AMD Core Performance Boost(CPB) is controlled by this new attribute
> file which
> > +        allow user to change all cores frequency boosting state. It supports
> both
> > +        ``active mode`` and ``passive mode`` control with below value write to
> it.
>
> Does it also support guided mode?

Yes,  guide mode is also supported and I tested it.  Looks like it is better to add the guide mode support info
Into the doc update.  Will update in V2.

# cat /sys/devices/system/cpu/amd_pstate/status
guided

check on and off lscpu output.

CPU NODE SOCKET CORE L1d:L1i:L2:L3 ONLINE    MAXMHZ   MINMHZ      MHZ
  0    0      0    0 0:0:0:0          yes 4201.0000 400.0000 2983.578
  1    0      0    1 1:1:1:0          yes 4201.0000 400.0000 2983.578
  2    0      0    2 2:2:2:0          yes 4201.0000 400.0000 2983.578
  3    0      0    3 3:3:3:0          yes 4201.0000 400.0000 2983.578
  4    0      0    4 4:4:4:0          yes 4201.0000 400.0000 2983.578

CPU NODE SOCKET CORE L1d:L1i:L2:L3 ONLINE    MAXMHZ   MINMHZ      MHZ
  0    0      0    0 0:0:0:0          yes 5759.0000 400.0000 2983.578
  1    0      0    1 1:1:1:0          yes 5759.0000 400.0000 2983.578
  2    0      0    2 2:2:2:0          yes 5759.0000 400.0000 2983.578
  3    0      0    3 3:3:3:0          yes 5759.0000 400.0000 2983.578
  4    0      0    4 4:4:4:0          yes 5759.0000 400.0000 2983.578


>
> > +
> > +        "0" Disable Core performance Boosting
> > +        "1" Enable  Core performance Boosting
> > +
> >   ``cpupower`` tool support for ``amd-pstate``
> >   ===============================================
> >