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

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Date: Mon, 29 Jan 2024 05:07:12 +0000
From: "Yuan, Perry" <Perry.Yuan@....com>
To: "Limonciello, Mario" <Mario.Limonciello@....com>,
	"rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
	"viresh.kumar@...aro.org" <viresh.kumar@...aro.org>, "Huang, Ray"
	<Ray.Huang@....com>, "Shenoy, Gautham Ranjal" <gautham.shenoy@....com>,
	"Petkov, Borislav" <Borislav.Petkov@....com>
CC: "Deucher, Alexander" <Alexander.Deucher@....com>, "Huang, Shimmer"
	<Shimmer.Huang@....com>, "Du, Xiaojian" <Xiaojian.Du@....com>, "Meng, Li
 (Jassmine)" <Li.Meng@....com>, "linux-pm@...r.kernel.org"
	<linux-pm@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 7/7] Documentation: cpufreq: amd-pstate: introduce the new
 cpu boost control method

[AMD Official Use Only - General]

> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@....com>
> Sent: Friday, January 26, 2024 11:47 PM
> To: Yuan, Perry <Perry.Yuan@....com>; rafael.j.wysocki@...el.com;
> viresh.kumar@...aro.org; Huang, Ray <Ray.Huang@....com>; Shenoy,
> Gautham Ranjal <gautham.shenoy@....com>; Petkov, Borislav
> <Borislav.Petkov@....com>
> Cc: Deucher, Alexander <Alexander.Deucher@....com>; Huang, Shimmer
> <Shimmer.Huang@....com>; Du, Xiaojian <Xiaojian.Du@....com>; Meng,
> Li (Jassmine) <Li.Meng@....com>; linux-pm@...r.kernel.org; linux-
> kernel@...r.kernel.org
> 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@....com>
> >
> > 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@....com>
> > ---
> >   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``
> >   ===============================================
> >