pepc-pstates - Man Page

-h

Show a short help message and exit.

-q

Be quiet.

-d

Print debugging information.

--version

Print version and exit.

-H HOSTNAME, --host HOSTNAME

Name of the host to run the command on.

-U USERNAME, --username USERNAME

Name of the user to use for logging into the remote host over SSH. The default user name is 'root'.

-K PRIVKEY, --priv-key PRIVKEY

Path to the private SSH key that should be used for logging into the remote host. By default the key is automatically found from standard paths like '$HOME/.ssh'.

-T TIMEOUT, --timeout TIMEOUT

SSH connection timeout in seconds, default is 8.

-D DATASET, --dataset DATASET

This option is for debugging and testing purposes only, it defines the dataset that will be used to emulate a host for running the command on. This option is typically used when running 'pepc' from the source code directory, which includes datasets for many different systems.

The argument can be the dataset path, 'all' to specify all available dataset or name in which case the following locations will be searched for.

1. './tests/data', in the directory of the running program
2. '$PEPC_DATA_PATH/tests/data'
3. '$HOME/.local/share/pepc/tests/data'
4. '/usr/local/share/pepc/tests/data'
5. '/usr/share/pepc/tests/data'

--force-color

Force coloring of the text output.

All sub-commans ('info', 'config', 'save') support the following target CPU specification options.

--cpus CPUS

The list can include individual CPU numbers and CPU number ranges. For example,'1-4,7,8,10-12' would mean CPUs 1 to 4, CPUs 7, 8, and 10 to 12. Use the special keyword 'all' to specify all CPUs.

--cores CORES

The list can include individual core numbers and core number ranges. For example, '1-4,7,8,10-12' would mean cores 1 to 4, cores 7, 8, and 10 to 1. Use the special keyword 'all' to specify all cores. This option has to be accompanied by the '--package' option, because core numbers are per-package.

--modules MODULES

The list can include individual module numbers and module number ranges. For example, '0,2-5' would mean module 0 and modules 2, 3, 4, and 5. Use the special keyword 'all' to specify all modules. Note, unlike core and die numbers, module numbers are absolute.

--dies DIES

The list can include individual die numbers and die number ranges. For example, '0-3,5' would mean dies 0 to 3, and die 5. Use the special keyword 'all' to specify all dies. On some systems, die numbers are globally unique, while on other systems they are relative to the package. In the latter case, this option has to be accompanied by the '--package' option.

--packages PACKAGES

The list can include individual package numbers and package number ranges. For example, '0,2-4' would mean package 0 and packages 2 to 4. Use the special keyword 'all' to specify all packages.

--core-siblings CORE_SIBLINGS

Core siblings are CPUs sharing the same core. The list can include individual core sibling indices or index ranges. For example, if a core includes CPUs 3 and 4, index '0' would mean CPU 3 and index '1' would mean CPU 4. This option can only be used to reference online CPUs, because Linux does not provide topology information for offline CPUs. In the example with CPUs 3 and 4, if CPU 3 was offline, then index '0' would mean CPU 4.

--module-siblings MODULE_SIBLINGS

Module siblings are CPUs sharing the same module. The list can include individual module sibling indices or index ranges. For example, if a module includes CPUs 3, 4, 5, and 6, index '0' would mean CPU 3, index '1' would mean CPU 4, and idex '3' would mean CPU 5. This option can only be used to reference online CPUs, because Linux does not provide topology information for offline CPUs. In the example with CPUs 3, 4, 5 and 6, if CPU 4 was offline, then index '1' would mean CPU 5.

Get P-states information for specified CPUs. By default, print all information about all CPUs.

Use target CPU specification options to specify the subset of CPUs, cores, dies, or packages.

--yaml

Print information in YAML format.

--override-cpu-model MODEL

This option is for debugging and testing purposes only. Provide the CPU model number which the tool treats the target system CPU as. For example, use 0x8F to treat the target system as Sapphire Rapids Xeon.

--list-mechanisms

List mechanisms available for reading P-states information.

--min-freq

Get minimum CPU frequency (details in 'min_freq').

--max-freq

Get maximum CPU frequency (details in 'max_freq').

--min-freq-limit

Get minimum supported CPU frequency (details in 'min_freq_limit').

--max-freq-limit

Get maximum supported CPU frequency (details in 'max_freq_limit').

--frequencies

Get acceptable CPU frequencies (details in 'frequencies').

--base-freq

Get base CPU frequency (details in 'base_freq').

--bus-clock

Get bus clock speed (details in 'bus_clock').

--min-oper-freq

Get minimum CPU operating frequency (details in 'min_oper_freq').

--max-eff-freq

Get maximum CPU efficiency frequency (details in 'max_eff_freq').

--turbo

Check if turbo is enabled or disabled (details in 'turbo').

--max-turbo-freq

Get maximum CPU turbo frequency (details in 'max_turbo_freq').

--min-uncore-freq

Get minimum uncore frequency (details in 'min_uncore_freq').

--max-uncore-freq

Get maximum uncore frequency (details in 'max_uncore_freq').

--min-uncore-freq-limit

Get minimum supported uncore frequency (details in 'min_uncore_freq_limit').

--max-uncore-freq-limit

Get maximum supported uncore frequency (details in 'max_uncore_freq_limit').

--hwp

Check if hardware power management is enabled or disabled (details in 'hwp').

--epp

Get EPP via sysfs (details in 'epp').

--epb

Get EPB via sysfs (details in 'epb').

--driver

Get CPU frequency driver (details in 'driver').

--intel-pstate-mode

Get operation mode of 'intel_pstate' driver (details in 'intel_pstate_mode').

--governor

Get CPU frequency governor (details in 'governor').

--governors

Get list of available CPU frequency governors (details in 'governors').

Configure P-states on specified CPUs. All options can be used without a parameter, in which case the currently configured value(s) will be printed.

Use target CPU specification options to specify the subset of CPUs, cores, dies, or packages.

--override-cpu-model MODEL

This option is for debugging and testing purposes only. Provide the CPU model number which the tool treats the target system CPU as. For example, use 0x8F to treat the target system as Sapphire Rapids Xeon.

-m MECHANISMS, --mechanisms MECHANISMS

Comma-separated list of mechanisms that are allowed to be used for configuring P-states. Use '--list-mechanisms' to get the list of available mechanisms. Note, many options support only one mechanism (e.g., 'sysfs'), some may support multiple (e.g., 'sysfs' and 'msr'). The mechanisms are tried in the specified order. By default, all mechanisms are allowed and the most preferred mechanisms will be tried first.

--list-mechanisms

List mechanisms available for configuring P-states.

--min-freq MIN_FREQ

Set minimum CPU frequency (details in 'min_freq').

--max-freq MAX_FREQ

Set maximum CPU frequency (details in 'max_freq').

--turbo on|off

Enable or disable turbo (details in 'turbo').

--min-uncore-freq MIN_UNCORE_FREQ

Set minimum uncore frequency (details in 'min_uncore_freq').

--max-uncore-freq MAX_UNCORE_FREQ

Set maximum uncore frequency (details in 'max_uncore_freq').

--epp EPP

Set EPP via sysfs (details in 'epp').

--epb EPB

Set EPB via sysfs (details in 'epb').

--intel-pstate-mode [MODE]

Set operation mode of 'intel_pstate' driver (details in 'intel_pstate_mode').

--governor [NAME]

Set CPU frequency governor (details in 'governor').

Save all the modifiable P-state settings into a file. This file can later be used for restoring P-state settings with the 'pepc pstates restore' command.

Use target CPU specification options to specify the subset of CPUs, cores, dies, or packages.

-o OUTFILE, --outfile OUTFILE

Name of the file to save the settings to (printed to standard output by default).

Restore P-state settings from a file previously created with the 'pepc pstates save' command.

-f INFILE, --from INFILE

Name of the file from which to restore the settings from, use "-" to read from the standard output.

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min_freq - Minimum CPU frequency

pepc pstates info --min-freq

pepc pstates config --min-freq=<value>

Minimum CPU frequency is the lowest frequency the CPU was configured the CPU to run at.

The default unit is 'Hz', but 'kHz', 'MHz', and 'GHz' can also be used (for example "900MHz").

The following special values are supported:

min

Minimum frequency supported by the Linux CPU frequency driver (see 'min_freq_limit').

max

Maximum frequency supported by the Linux CPU frequency driver (see 'max_freq_limit').

base, hfm, P1

Base CPU frequency (see 'base_freq').

eff, lfm, Pn

Maximum CPU efficiency frequency (see 'max_eff_freq').

Pm

Minimum CPU operating frequency (see 'min_oper_freq').

Note, on some systems 'Pm' is lower than 'lfm'. For example, 'Pm' may be 500MHz, while 'lfm' may be 800MHz. On those system, Linux may be using 'lfm' as the minimum supported frequency limit. So from Linux perspective, the minimum frequency may be 800MHz, not 500MHz. In this case '--min-freq 500MHz --mechanisms sysfs' will fail, while '--min-freq 500MHz --mechanisms sysfs' will succeed. And '--min-freq 500MHz' will also succeed, because by default, pepc tries all the available mechanisms.

sysfs "/sys/devices/system/cpu/policy0/scaling_min_freq", where '0' is replaced with desired CPU number.

msr MSR_HWP_REQUEST (0x774), bits 7:0.

This property has CPU scope.

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max_freq - Maximum CPU frequency

pepc pstates info --max-freq

pepc pstates config --max-freq=<value>

Maximum CPU frequency is the highest frequency the CPU was configured to run at.

The default unit is 'Hz', but 'kHz', 'MHz', and 'GHz' can also be used (for example '900MHz').

The following special values are supported:

min

Minimum frequency supported by the Linux CPU frequency driver (see 'min_freq_limit').

max

Maximum frequency supported by the Linux CPU frequency driver (see 'max_freq_limit').

base, hfm, P1

Base CPU frequency (see 'base_freq').

eff, lfm, Pn

Maximum CPU efficiency frequency (see 'max_eff_freq').

Pm

Minimum CPU operating frequency (see 'min_oper_freq').

sysfs "/sys/devices/system/cpu/policy0/scaling_max_freq", where '0' is replaced with desired CPU number.

msr MSR_HWP_REQUEST (0x774), bits 15:8.

  *   *   *   *   *

This property has CPU scope.

min_freq_limit - Minimum supported CPU frequency

pepc pstates info --min-freq-limit

Minimum supported CPU frequency is the lowest frequency the CPU can be configured to run at.

sysfs "/sys/devices/system/cpu/policy0/cpuinfo_min_freq", where '0' is replaced with desired CPU number.

This property has CPU scope.

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max_freq_limit - Maximum supported CPU frequency

pepc pstates info --min-freq-limit

Maximum supported CPU frequency is the highest frequency the CPU can be configured to run at.

sysfs "/sys/devices/system/cpu/policy0/cpuinfo_max_freq", where '0' is replaced with desired CPU number.

This property has CPU scope.

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frequencies - acceptable CPU frequencies

pepc pstates info --frequencies

List of CPU frequencies exposed by the Linux CPU frequency driver and available for the users via '--min-freq' and '--max-freq' options.

sysfs "/sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies", '0' is replaced with desired CPU number.

doc In case of Intel CPUs and 'intel_idle' driver, assume all frequencies from 'min_freq_limit' to 'max_freq_limit' with 'bus_clock' step.

This property has CPU scope.

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base_freq - Base CPU frequency

pepc pstates info --base-freq

Base CPU frequency is the highest sustainable CPU frequency. This frequency is also referred to as "guaranteed frequency", HFM (High Frequency Mode), or P1.

The base frequency is acquired from a sysfs file or from an MSR register, depending on platform and the CPU frequency driver.

sysfs "/sys/devices/system/cpu/policy0/base_frequency", where '0' is replaced with desired CPU number. If this file does not exist, the "/sys/devices/system/cpu/cpu0/cpufreq/bios_limit" sysfs file is used (where '0' is replaced with desired CPU number).

msr MSR_PLATFORM_INFO (0xCE), bits 15:8.

This property has CPU scope.

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bus_clock - Bus clock speed.

pepc pstates info --bus-clock

Bus clock refers to how quickly the system bus can move data from one computer component to the other.

msr MSR_FSB_FREQ (0xCD), bits 2:0. doc 100MHz on modern Intel platforms.

This property has package scope. Exceptions: Silvermonts and Airmonts have module scope.

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min_oper_freq - Minimum CPU operating frequency

pepc pstates info --min-oper-freq

Minimum operating frequency is the lowest possible frequency the CPU can operate at. Depending on the CPU model, this frequency may or may not be directly available to the OS, but the platform may use it in certain situations (e.g., in some C-states). This frequency is also referred to as Pm.

msr MSR_PLATFORM_INFO (0xCE), bits 55:48.

This property has CPU scope.

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max_eff_freq - Maximum CPU efficiency frequency

pepc pstates info --max-eff-freq

Maximum efficiency frequency is the most energy efficient CPU frequency. This frequency is also referred to as LFM (Low Frequency Mode) or Pn.

msr MSR_PLATFORM_INFO (0xCE), bits 47:40.

This property has CPU scope.

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turbo - Turbo

pepc pstates info --turbo

pepc pstates config --turbo=<on|off>

When turbo is enabled, the CPUs can automatically run at a frequency greater than base frequency.

sysfs Location of the turbo knob in sysfs depends on the CPU frequency driver.

intel_pstate - "/sys/devices/system/cpu/intel_pstate/no_turbo"

acpi-cpufreq - "/sys/devices/system/cpu/cpufreq/boost"

This property has global scope.

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max_turbo_freq - Maximum CPU turbo frequency

pepc pstates info --max-turbo-freq

Maximum 1-core turbo frequency is the highest frequency a single CPU can operate at. This frequency is also referred to as max. 1-core turbo and P01.

msr MSR_TURBO_RATIO_LIMIT (0x1AD), bits 7:0.

This property has CPU scope.

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min_uncore_freq - Minimum uncore frequency

pepc pstates info --min-uncore-freq

pepc pstates config --min-uncore-freq=<value>

Minimum uncore frequency is the lowest frequency the OS configured the CPU to run at, via sysfs knobs.

The default unit is 'Hz', but 'kHz', 'MHz', and 'GHz' can also be used (for example '900MHz').

The following special values are supported:

min

Minimum uncore frequency supported (see 'min_freq_limit').

max

Maximum uncore frequency supported (see 'max_freq_limit').

mdl

Middle uncore frequency between minimum and maximum rounded to nearest 100MHz.

sysfs

In case of 'intel_uncore_frequency_tpmi' driver, file "/sys/devices/system/cpu/intel_uncore_frequency/uncore00/min_freq_khz", where '00' is replaced with the uncore number corresponding to the desired package and die numbers.

In case of 'intel_uncore_frequency' driver, file "/sys/devices/system/cpu/intel_uncore_frequency/package_00_die_01/min_freq_khz", where '00' is replaced with desired package number and '01' is replaced with desired die number.

This property has die scope.

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max_uncore_freq - Maximum uncore frequency

pepc pstates info --max-uncore-freq

pepc pstates config --max-uncore-freq=<value>

Maximum uncore frequency is the highest frequency the OS configured the CPU to run at, via sysfs knobs.

The default unit is 'Hz', but 'kHz', 'MHz', and 'GHz' can also be used (for example "900MHz").

The following special values are supported:

min

Minimum uncore frequency supported (see 'min_freq_limit').

max

Maximum uncore frequency supported (see 'max_freq_limit').

mdl

Middle uncore frequency between minimum and maximum rounded to nearest 100MHz.

sysfs

In case of 'intel_uncore_frequency_tpmi' driver, file "/sys/devices/system/cpu/intel_uncore_frequency/uncore00/max_freq_khz", where '00' is replaced with the uncore number corresponding to the desired package and die numbers.

In case of 'intel_uncore_frequency' driver, file "/sys/devices/system/cpu/intel_uncore_frequency/package_00_die_01/max_freq_khz", where '00' is replaced with desired package number and '01' is replaced with desired die number.

This property has die scope.

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min_uncore_freq_limit - Minimum supported uncore frequency

pepc pstates info --min-uncore-freq-limit

Minimum supported uncore frequency is the lowest uncore frequency supported by the OS.

sysfs

In case of 'intel_uncore_frequency_tpmi' driver, file "/sys/devices/system/cpu/intel_uncore_frequency/uncore00/initial_min_freq_khz", where '00' is replaced with the uncore number corresponding to the desired package and die numbers.

"/sys/devices/system/cpu/intel_uncore_frequency/package_00_die_01/initial_min_freq_khz", where '00' is replaced with desired package number and '01' is replaced with desired die number.

This property has die scope.

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max_uncore_freq_limit - Maximum supported uncore frequency

pepc pstates info --max-uncore-freq-limit

Maximum supported uncore frequency is the highest uncore frequency supported by the OS.

sysfs

In case of 'intel_uncore_frequency_tpmi' driver, file "/sys/devices/system/cpu/intel_uncore_frequency/uncore00/initial_max_freq_khz", where '00' is replaced with the uncore number corresponding to the desired package and die numbers.

"/sys/devices/system/cpu/intel_uncore_frequency/package_00_die_01/initial_max_freq_khz", where '00' is replaced with desired package number and '01' with desired die number.

This property has die scope.

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hwp - Hardware power management

pepc pstates info --hwp

When hardware power management is enabled, CPUs can automatically scale their frequency without active OS involvement.

msr MSR_PM_ENABLE (0x770), bit 0.

This property has global scope.

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epp - Energy Performance Preference

pepc pstates info --epp

pepc pstates config --epp=<value>

Energy Performance Preference is a hint to the CPU on energy efficiency vs performance. EPP value is a number in range of 0-255 (maximum energy efficiency to maximum performance), or a policy name.

Mechanisms ---------

sysfs "/sys/devices/system/cpu/cpufreq/policy0/energy_performance_preference", where '0' is replaced with desired CPU number.

msr MSR_HWP_REQUEST (0x774), bits 31:24.

This property has CPU scope.

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epb - Energy Performance Bias

pepc pstates info --epb

pepc pstates config --epb=<value>

Energy Performance Bias is a hint to the CPU on energy efficiency vs performance. EBP value is a number in range of 0-15 (maximum performance to maximum energy efficiency), or a policy name.

sysfs "/sys/devices/system/cpu/cpu0/power/energy_perf_bias", where '0' is replaced with desired CPU number.

msr MSR_ENERGY_PERF_BIAS (0x1B0), bits 3:0.

This property has CPU scope on most platforms. However, on Silvermont systems it has core scope and on Westmere and Sandybridge systems it has package scope.

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driver - CPU frequency driver

pepc pstates info --driver

CPU frequency driver enumerates and requests the P-states available on the platform.

sysfs "/sys/devices/system/cpu/cpufreq/policy0/scaling_driver", where '0' is replaced with desired CPU number.

This property has global scope.

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intel_pstate_mode - Operation mode of 'intel_pstate' driver

pepc pstates info --intel-pstate-mode

pepc pstates config --intel-pstate-mode=<mode>

The 'intel_pstate' driver has 3 operation modes: 'active', 'passive' and 'off'. The main difference between the active and passive mode is in which frequency governors are used - the generic Linux governors (passive mode) or the custom, built-in 'intel_pstate' driver governors (active mode).

sysfs "/sys/devices/system/cpu/intel_pstate/status".

This property has global scope.

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governor - CPU frequency governor

pepc pstates info --governor

pepc pstates config --governor=<name>

CPU frequency governor decides which P-state to select on a CPU depending on CPU business and other factors.

sysfs "/sys/devices/system/cpu/cpufreq/policy0/scaling_governor", where '0' is replaced with desired CPU number.

This property has CPU scope.

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governors - Available CPU frequency governors

pepc pstates info --governors

CPU frequency governors decide which P-state to select on a CPU depending on CPU business and other factors. Different governors implement different selection policy.

sysfs "/sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors", where '0' is replaced with desired CPU number.

This property has global scope.