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Message-ID:
<CYYPR12MB86559CB690A186BD0F87B7739CCF2@CYYPR12MB8655.namprd12.prod.outlook.com>
Date: Wed, 19 Jun 2024 03:46:38 +0000
From: "Yuan, Perry" <Perry.Yuan@....com>
To: "rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
"viresh.kumar@...aro.org" <viresh.kumar@...aro.org>, "Shenoy, Gautham Ranjal"
<gautham.shenoy@....com>, "Petkov, Borislav" <Borislav.Petkov@....com>,
"Limonciello, Mario" <Mario.Limonciello@....com>
CC: "viresh.kumar@...aro.org" <viresh.kumar@...aro.org>, "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>, "Yuan, Perry"
<Perry.Yuan@....com>
Subject: RE: [PATCH v11 3/9] cpufreq: introduce init_boost callback to
initialize boost state for pstate drivers
[Public]
Hi Rafael
> -----Original Message-----
> From: Yuan, Perry <Perry.Yuan@....com>
> Sent: Friday, June 14, 2024 10:43 AM
> To: Limonciello, Mario <Mario.Limonciello@....com>; Shenoy, Gautham
> Ranjal <gautham.shenoy@....com>; Petkov, Borislav
> <Borislav.Petkov@....com>
> Cc: rafael.j.wysocki@...el.com; viresh.kumar@...aro.org; 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 v11 3/9] cpufreq: introduce init_boost callback to
> initialize boost state for pstate drivers
>
> [AMD Official Use Only - AMD Internal Distribution Only]
>
> [AMD Official Use Only - AMD Internal Distribution Only]
>
> > -----Original Message-----
> > From: Limonciello, Mario <Mario.Limonciello@....com>
> > Sent: Friday, June 14, 2024 1:55 AM
> > To: Yuan, Perry <Perry.Yuan@....com>; Shenoy, Gautham Ranjal
> > <gautham.shenoy@....com>; Petkov, Borislav
> <Borislav.Petkov@....com>
> > Cc: rafael.j.wysocki@...el.com; viresh.kumar@...aro.org; 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 v11 3/9] cpufreq: introduce init_boost callback to
> > initialize boost state for pstate drivers
> >
> > On 6/13/2024 02:25, Perry Yuan wrote:
> > > Introduce a new init_boost callback in cpufreq to initialize the
> > > boost state for specific pstate drivers. This initialization is
> > > required before calling the set_boost interface for each CPU.
> > >
> > > The init_boost callback will set up and synchronize each CPU's
> > > current boost state before invoking the set_boost function. Without
> > > this step, the boost state may be inconsistent across CPUs.
> > >
> > > Signed-off-by: Perry Yuan <perry.yuan@....com>
> > > ---
> > > drivers/cpufreq/cpufreq.c | 12 ++++++++++--
> > > include/linux/cpufreq.h | 2 ++
> > > 2 files changed, 12 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > > index 1fdabb660231..e1a4730f4f8c 100644
> > > --- a/drivers/cpufreq/cpufreq.c
> > > +++ b/drivers/cpufreq/cpufreq.c
> > > @@ -1429,8 +1429,16 @@ static int cpufreq_online(unsigned int cpu)
> > > goto out_free_policy;
> > > }
> > >
> > > - /* Let the per-policy boost flag mirror the cpufreq_driver
> > boost during init */
> > > - policy->boost_enabled = cpufreq_boost_enabled() &&
> > policy_has_boost_freq(policy);
> > > + /* init boost state to prepare set_boost callback for
> > > + each CPU
> > */
> > > + if (cpufreq_driver->init_boost) {
> > > + ret = cpufreq_driver->init_boost(policy);
> > > + if (ret)
> > > + pr_debug("%s: %d: initialization boost
> > failed\n", __func__,
> > > + __LINE__);
> >
> > The message should have the subject at the beginning. IE:
> >
> > "boost initialization failed\n"
> >
> > Also, isn't this fatal if init failed? IE shouldn't failing have a:
>
>
> Firstly, I also add the " goto out_free_policy", and removed later, because I
> think it is a little risky to fail the whole online process if driver init boost
> callback failed.
> If driver init boost failed, it just let boost control function lost, but online
> initialize failed and go to free the policy, it is a big problem.
> I am ok to add the error handling if maintainer agree to see the potential
> online function aborting. 😊
>
> Perry.
>
> >
> > goto out_free_policy;
> >
> > > + } else {
> > > + /* Let the per-policy boost flag mirror the
> > cpufreq_driver boost during init */
> > > + policy->boost_enabled = cpufreq_boost_enabled()
> > && policy_has_boost_freq(policy);
> > > + }
> > >
> > > /*
> > > * The initialization has succeeded and the policy is online.
> > > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index
> > > 20f7e98ee8af..0698c0292d8f 100644
> > > --- a/include/linux/cpufreq.h
> > > +++ b/include/linux/cpufreq.h
> > > @@ -409,6 +409,8 @@ struct cpufreq_driver {
> > > bool boost_enabled;
> > > int (*set_boost)(struct cpufreq_policy *policy, int state);
> > >
> > > + /* initialize boost state to be consistent before calling set_boost */
> > > + int (*init_boost)(struct cpufreq_policy *policy);
> > > /*
> > > * Set by drivers that want to register with the energy model after the
> > > * policy is properly initialized, but before the governor is started.
Could you please help to review this cpufreq change to add init_boost callback for the pstate driver?
We need to add this to initialize boost_supported and boost_state according to SBIOS , then user could change the boost setting as preference.
Perry.
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