linux-kernel - RE: [PATCH v12 6/9] cpufreq: amd-pstate: Add set

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Date: Fri, 21 Jun 2024 05:54:38 +0000
From: "Yuan, Perry" <Perry.Yuan@....com>
To: "Shenoy, Gautham Ranjal" <gautham.shenoy@....com>,
	"rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>, "Limonciello,
 Mario" <Mario.Limonciello@....com>, "viresh.kumar@...aro.org"
	<viresh.kumar@...aro.org>
CC: "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 v12 6/9] cpufreq: amd-pstate: Add set_boost callback for
 active mode

[AMD Official Use Only - AMD Internal Distribution Only]

Hi Gautham.

> -----Original Message-----
> From: Shenoy, Gautham Ranjal <gautham.shenoy@....com>
> Sent: Friday, June 21, 2024 1:39 PM
> To: Yuan, Perry <Perry.Yuan@....com>; rafael.j.wysocki@...el.com;
> Limonciello, Mario <Mario.Limonciello@....com>; viresh.kumar@...aro.org
> Cc: 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 v12 6/9] cpufreq: amd-pstate: Add set_boost callback for
> active mode
>
> Perry Yuan <perry.yuan@....com> writes:
>
> > Add support for the set_boost callback in the active mode driver to
> > enable boost control via the cpufreq core. This ensures a consistent
> > boost control interface across all pstate modes, including passive
> > mode, guided mode, and active mode.
> >
> > With this addition, all three pstate modes can support the same boost
> > control interface with unique interface and global CPB control. Each
> > CPU also supports individual boost control, allowing global CPB to
> > change all cores' boost states simultaneously. Specific CPUs can
> > update their boost states separately, ensuring all cores' boost states
> > are synchronized.
> >
> > Signed-off-by: Perry Yuan <perry.yuan@....com>
>
>
> Acked-by: Gautham R. Shenoy <gautham.shenoy@....com>
>
> With this patch, is there any specific reason why we still need
> /sys/devices/system/cpu/amd_pstate/boost_enable ?

Mario suggested to use global and PER CPU control in the previous thread.
So now we have one global "/sys/devices/system/cpu/amd_pstate/cpb_boost" and
Per CPU control "sys/devices/system/cpu/cpuX/cpufreq/boost "
You can see more details in the cover letter.

Perry.
>
>
> > ---
> >  drivers/cpufreq/amd-pstate.c | 18 +++++-------------
> >  1 file changed, 5 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 1c2320808ae1..299e52d4b17e
> 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -699,20 +699,11 @@ static int amd_pstate_set_boost(struct
> cpufreq_policy *policy, int state)
> >             pr_err("Boost mode is not supported by this processor or
> SBIOS\n");
> >             return -ENOTSUPP;
> >     }
> > +   mutex_lock(&amd_pstate_driver_lock);
> > +   ret = amd_pstate_cpu_boost(policy->cpu, state);
> > +   mutex_unlock(&amd_pstate_driver_lock);
> >
> > -   if (state)
> > -           policy->cpuinfo.max_freq = cpudata->max_freq;
> > -   else
> > -           policy->cpuinfo.max_freq = cpudata->nominal_freq * 1000;
> > -
> > -   policy->max = policy->cpuinfo.max_freq;
> > -
> > -   ret = freq_qos_update_request(&cpudata->req[1],
> > -                                 policy->cpuinfo.max_freq);
> > -   if (ret < 0)
> > -           return ret;
> > -
> > -   return 0;
> > +   return ret < 0 ? ret : 0;
> >  }
> >
> >  static int amd_pstate_boost_set(struct amd_cpudata *cpudata) @@
> > -1868,6 +1859,7 @@ static struct cpufreq_driver amd_pstate_epp_driver =
> {
> >     .resume         = amd_pstate_epp_resume,
> >     .update_limits  = amd_pstate_update_limits,
> >     .init_boost     = amd_pstate_init_boost,
> > +   .set_boost      = amd_pstate_set_boost,
> >     .name           = "amd-pstate-epp",
> >     .attr           = amd_pstate_epp_attr,
> >  };
> > --
> > 2.34.1
>
> --
> Thanks and Regards
> gautham.