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SubjectRe: [PATCH v10 6/7] cpufreq: amd-pstate: introduce per CPU frequency boost control
Date
Hello.

On středa 8. května 2024 9:21:11, SELČ Perry Yuan wrote:
> Add a new sysfs attribute file to support per CPU frequency boost
> control, allowing individual CPUs to enable or disable CPB separately.
>
> The new sysfs attribute file is located at below path,
> `/sys/devices/system/cpu/cpuX/cpufreq/boost`,
> where `X` represents the CPU number.
>
> To disable CPB for a specific CPU, you can use the following command:
> $ sudo bash -c "echo 0 > /sys/devices/system/cpu/cpuX/cpufreq/boost"
>
> After disabling CPB, the CPU frequency will no longer boost beyond
> the base frequency for that particular CPU.
>
> for example:
> ----------------------------------------------------------------------
> CPU NODE SOCKET CORE L1d:L1i:L2:L3 ONLINE MAXMHZ MINMHZ MHZ
> 0 0 0 0 0:0:0:0 yes 4208.0000 400.0000 1666.7740
> 1 0 0 0 0:0:0:0 yes 4208.0000 400.0000 400.0000
>
> ----------------------------------------------------------------------
> $ sudo bash -c "echo 0 > /sys/devices/system/cpu/cpu0/cpufreq/boost"
>
> CPU NODE SOCKET CORE L1d:L1i:L2:L3 ONLINE MAXMHZ MINMHZ MHZ
> 0 0 0 0 0:0:0:0 yes 3501.0000 400.0000 4154.3140
> 1 0 0 0 0:0:0:0 yes 4208.0000 400.0000 400.0000
>
> Please be aware that modifying the global variable
> `amd_pstate_global_params.cpb_boost` will overwrite the individual CPU settings.
>
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
> ---
> drivers/cpufreq/amd-pstate.c | 27 +++++++++++++++++++++++++++
> 1 file changed, 27 insertions(+)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 11bce2c1db32..cb0055e7c842 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -1371,6 +1371,30 @@ static int amd_pstate_cpu_boost(int cpu, bool state)
> return ret < 0 ? ret : 0;
> }
>
> +static ssize_t show_boost(struct cpufreq_policy *policy, char *buf)
> +{
> + struct amd_cpudata *cpudata = policy->driver_data;
> + bool boost_val;
> +
> + boost_val = READ_ONCE(cpudata->boost_state);
> +
> + return sysfs_emit(buf, "%u\n", boost_val);
> +}
> +
> +static ssize_t store_boost(
> + struct cpufreq_policy *policy, const char *buf, size_t count)
> +{
> + bool boost_val;
> + int ret;
> +
> + if (sscanf(buf, "%d", &boost_val) != 1)

This will generate warning. IIUC, sscanf() doesn't work with booleans directly, so you'd probably want to read the value into an (unsigned) integer, and then cast it to bool.

> + return -EINVAL;
> +
> + ret = amd_pstate_cpu_boost(policy->cpu, boost_val);
> +
> + return ret < 0 ? ret : count;
> +}
> +
> static ssize_t cpb_boost_show(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> @@ -1416,6 +1440,7 @@ cpufreq_freq_attr_ro(amd_pstate_prefcore_ranking);
> cpufreq_freq_attr_ro(amd_pstate_hw_prefcore);
> cpufreq_freq_attr_rw(energy_performance_preference);
> cpufreq_freq_attr_ro(energy_performance_available_preferences);
> +cpufreq_freq_attr_rw(boost);
> static DEVICE_ATTR_RW(status);
> static DEVICE_ATTR_RO(prefcore);
> static DEVICE_ATTR_RW(cpb_boost);
> @@ -1426,6 +1451,7 @@ static struct freq_attr *amd_pstate_attr[] = {
> &amd_pstate_highest_perf,
> &amd_pstate_prefcore_ranking,
> &amd_pstate_hw_prefcore,
> + &boost,
> NULL,
> };
>
> @@ -1437,6 +1463,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
> &amd_pstate_hw_prefcore,
> &energy_performance_preference,
> &energy_performance_available_preferences,
> + &boost,
> NULL,
> };
>
>


--
Oleksandr Natalenko (post-factum)[unhandled content-type:application/pgp-signature]
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