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Message-ID: <caeaf2a6-1156-0649-d8bd-b66ab99b589a@amd.com>
Date: Mon, 7 Nov 2022 13:09:41 -0600
From: "Limonciello, Mario" <mario.limonciello@....com>
To: Perry Yuan <Perry.Yuan@....com>, rafael.j.wysocki@...el.com,
ray.huang@....com, viresh.kumar@...aro.org
Cc: Deepak.Sharma@....com, Nathan.Fontenot@....com,
Alexander.Deucher@....com, Shimmer.Huang@....com,
Xiaojian.Du@....com, Li.Meng@....com, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org, wyes.karny@....com
Subject: Re: [PATCH v3 7/8] cpufreq: amd-pstate: add frequency dynamic boost
sysfs control
On 11/7/2022 12:16, Limonciello, Mario wrote:
> +wyes.karny@....com
>
> On 11/7/2022 11:57, 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@....com>
>> ---
>> drivers/cpufreq/amd-pstate.c | 53 ++++++++++++++++++++++++++++++++++++
>> 1 file changed, 53 insertions(+)
>
> Make sure that you update the documentation for this new sysfs file as
> well.
>
>>
>> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
>> index 841b1e2383b8..6958c5fd9e1c 100644
>> --- a/drivers/cpufreq/amd-pstate.c
>> +++ b/drivers/cpufreq/amd-pstate.c
>> @@ -786,12 +786,46 @@ 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_pstate_dynamic_boost(struct kobject *kobj,
>> + struct kobj_attribute *attr, char *buf)
>> +{
>> + return sprintf(buf, "%u\n", cppc_boost);
>> +}
>> +
>> +static ssize_t store_pstate_dynamic_boost(struct kobject *a,
>> + struct kobj_attribute *b,
>> + const char *buf, size_t count)
>> +{
>> + unsigned int input;
>> + int ret;
>> +
>> + ret = kstrtouint(buf, 10, &input);
>> + if (ret)
>> + return ret;
>
> To be more flexible maybe kstrtobool would be better here instead?
>
>> +
>> + mutex_lock(&amd_pstate_driver_lock);
>> + cppc_boost = !!input;
>> + 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(pstate_dynamic_boost);
>> static struct freq_attr *amd_pstate_attr[] = {
>> &amd_pstate_max_freq,
>> @@ -809,6 +843,15 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
>> NULL,
>> };
>> +static struct attribute *pstate_global_attributes[] = {
>> + &pstate_dynamic_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;
>> @@ -1416,6 +1459,16 @@ static int __init amd_pstate_init(void)
>> pr_err("failed to register amd pstate driver with return %d\n",
>> ret);
>> + amd_pstate_kobj = kobject_create_and_add("amd-pstate",
>> &cpu_subsys.dev_root->kobj);
>> + if (!amd_pstate_kobj)
>> + pr_err("amd-pstate: Global sysfs registration failed.\n");
>> +
>> + ret = sysfs_create_group(amd_pstate_kobj,
>> &amd_pstate_global_attr_group);
>> + if (ret) {
>> + pr_err("amd-pstate: Sysfs attribute export failed with error
>> %d.\n",
>> + ret);
>
> amd-pstate can currently be a module too. So don't you need the
> matching cleanup path for this code too?
I noticed your patch 3/8 makes this change, so this specific comment
might not be as important anymore.
>
> Also, regarding the error messages you don't need to prefix with
> "amd-pstate: ", amd-pstate.c already sets `pr_fmt`.
Also, shouldn't failing to make these attributes fail the rest of
amd-pstate init rather than just showing error messages?
>
>> + }
>> +
>> return ret;
>> }
>> device_initcall(amd_pstate_init);
>
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