sysfs-cpufreq.md | Cheatsheet¶
cpufreq-stats is a driver that provides CPU frequency statistics for each CPU. These statistics are provided in /sysfs as a bunch of read_only interfaces.
This interface (when configured) will appear in a separate directory under cpufreq in /sysfs (
This driver is designed to be independent of any particular cpufreq_driver that may be running on your CPU. So, it will work with any cpufreq_driver.
The scaling governor currently attached to this policy or (if the intel_pstate scaling driver is in use) the scaling algorithm provided by the driver that is currently applied to this policy.
This attribute is read-write and writing to it will cause a new scaling governor to be attached to this policy or a new scaling algorithm provided by the scaling driver to be applied to it (in the intel_pstate case), as indicated by the string written to this attribute (which must be one of the names listed by the scaling_available_governors attribute described above).
When attached to a policy object, this governor causes the highest frequency, within the scaling_max_freq policy limit, to be requested for that policy.
The request is made once at that time the governor for the policy is set to performance and whenever the scaling_max_freq or scaling_min_freq policy limits change after that.
When attached to a policy object, this governor causes the lowest frequency, within the scaling_min_freq policy limit, to be requested for that policy.
The request is made once at that time the governor for the policy is set to powersave and whenever the scaling_max_freq or scaling_min_freq policy limits change after that.
This governor does not do anything by itself. Instead, it allows user space to set the CPU frequency for the policy it is attached to by writing to the scaling_setspeed attribute of that policy.
This governor uses CPU utilization data available from the CPU scheduler. It generally is regarded as a part of the CPU scheduler, so it can access the scheduler’s internal data structures directly.
This governor uses CPU load as a CPU frequency selection metric.
It generally selects CPU frequencies proportional to the estimated load, so that the value of the cpuinfo_max_freq policy attribute corresponds to the load of 1 (or 100%), and the value of the cpuinfo_min_freq policy attribute corresponds to the load of 0, unless when the load exceeds a (configurable) speedup threshold, in which case it will go straight for the highest frequency it is allowed to use (the scaling_max_freq policy limit).