RE: [PATCH v4 7/9] cpufreq: amd-pstate: add frequency dynamic boost sysfs control

[Yuan, Perry]

[AMD Official Use Only - General]



> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@xxxxxxx>
> Sent: Tuesday, November 15, 2022 6:30 AM
> To: Yuan, Perry <Perry.Yuan@xxxxxxx>; rafael.j.wysocki@xxxxxxxxx; Huang,
> Ray <Ray.Huang@xxxxxxx>; viresh.kumar@xxxxxxxxxx
> Cc: Sharma, Deepak <Deepak.Sharma@xxxxxxx>; Fontenot, Nathan
> <Nathan.Fontenot@xxxxxxx>; Deucher, Alexander
> <Alexander.Deucher@xxxxxxx>; Huang, Shimmer
> <Shimmer.Huang@xxxxxxx>; Du, Xiaojian <Xiaojian.Du@xxxxxxx>; Meng,
> Li (Jassmine) <Li.Meng@xxxxxxx>; Karny, Wyes <Wyes.Karny@xxxxxxx>;
> linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v4 7/9] cpufreq: amd-pstate: add frequency dynamic
> boost sysfs control
> 
> On 11/10/2022 11:58, Perry Yuan wrote:
> > Add one sysfs entry to control the CPU cores frequency boost state The
> > attribute file can allow user to set max performance boosted or
> > keeping at normal perf level.
> >
> > Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
> > ---
> >   drivers/cpufreq/amd-pstate.c | 66
> ++++++++++++++++++++++++++++++++++--
> >   1 file changed, 64 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 645706d65173..b71bfbbb7639
> 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -765,12 +765,46 @@ static ssize_t
> show_energy_performance_preference(
> >   	return  sprintf(buf, "%s\n", energy_perf_strings[preference]);
> >   }
> >
> > +static void amd_pstate_update_policies(void) {
> > +	int cpu;
> > +
> > +	for_each_possible_cpu(cpu)
> > +		cpufreq_update_policy(cpu);
> > +}
> > +
> > +static ssize_t show_boost(struct kobject *kobj,
> > +				struct kobj_attribute *attr, char *buf) {
> > +	return sprintf(buf, "%u\n", cppc_boost);
> 
> For new code I believe you should use the new helper sysfs_emit() instead.

Make sense, changed in v5.
Thanks .

Perry. 

> 
> > +}
> > +
> > +static ssize_t store_boost(struct kobject *a,
> > +				       struct kobj_attribute *b,
> > +				       const char *buf, size_t count) {
> > +	bool new_state;
> > +	int ret;
> > +
> > +	ret = kstrtobool(buf, &new_state);
> > +	if (ret)
> > +		return -EINVAL;
> > +
> > +	mutex_lock(&amd_pstate_driver_lock);
> > +	cppc_boost = !!new_state;
> > +	amd_pstate_update_policies();
> > +	mutex_unlock(&amd_pstate_driver_lock);
> > +
> > +	return count;
> > +}
> > +
> >   cpufreq_freq_attr_ro(amd_pstate_max_freq);
> >   cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
> >
> >   cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> >   cpufreq_freq_attr_rw(energy_performance_preference);
> >   cpufreq_freq_attr_ro(energy_performance_available_preferences);
> > +define_one_global_rw(boost);
> >
> >   static struct freq_attr *amd_pstate_attr[] = {
> >   	&amd_pstate_max_freq,
> > @@ -788,6 +822,15 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
> >   	NULL,
> >   };
> >
> > +static struct attribute *pstate_global_attributes[] = {
> > +	&boost.attr,
> > +	NULL
> > +};
> > +
> > +static const struct attribute_group amd_pstate_global_attr_group = {
> > +	.attrs = pstate_global_attributes,
> > +};
> > +
> >   static inline void update_boost_state(void)
> >   {
> >   	u64 misc_en;
> > @@ -1398,9 +1441,28 @@ static int __init amd_pstate_init(void)
> >
> >   	ret = cpufreq_register_driver(default_pstate_driver);
> >   	if (ret)
> > -		pr_err("failed to register amd pstate driver with
> return %d\n",
> > -		       ret);
> > +		pr_err("failed to register driver with return %d\n", ret);
> > +
> > +	amd_pstate_kobj = kobject_create_and_add("amd-pstate",
> &cpu_subsys.dev_root->kobj);
> > +	if (!amd_pstate_kobj) {
> > +		ret = -EINVAL;
> > +		pr_err("global sysfs registration failed.\n");
> > +		goto kobject_free;
> > +	}
> > +
> > +	ret = sysfs_create_group(amd_pstate_kobj,
> &amd_pstate_global_attr_group);
> > +	if (ret) {
> > +		pr_err("sysfs attribute export failed with error %d.\n", ret);
> > +		goto global_attr_free;
> > +	}
> > +
> > +	return ret;
> >
> > +global_attr_free:
> > +	kobject_put(amd_pstate_kobj);
> > +kobject_free:
> > +	kfree(cpudata);
> > +	cpufreq_unregister_driver(default_pstate_driver);
> >   	return ret;
> >   }
> >   device_initcall(amd_pstate_init);

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