pepc-cstates - 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 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.

Get information about C-states on specified CPUs. By default, prints all information for all CPUs.

--cpus CPUS

List of CPUs to get information about. 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

List of cores to get information about. 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 12. Use the special keyword 'all' to specify all cores. This option has to be accompanied by '--package' option, because core numbers are per-package

--packages PACKAGES

List of packages to get information about. 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

List of core sibling indices to get information about. The list can include individual core sibling indices or index ranges. For example, core x includes CPUs 3 and 4, '0' would mean CPU 3 and '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 previous example if CPU 3 was offline, then '0' would mean CPU 4.

--yaml

Print information in YAML format.

--override-cpu-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.

--cstates [CSTATES]

Comma-separated list of C-states to get information about. C-states should be specified by name (e.g., 'C1'). Use 'all' to specify all the available Linux C-states (this is the default). Note, there is a difference between Linux C-states (e.g., 'C6') and hardware C-states (e.g., Core C6 or Package C6 on many Intel platforms). The former is what Linux can request, and on Intel hardware this is usually about various 'mwait' instruction hints. The latter are platform-specific hardware state, entered upon a Linux request.

--pkg-cstate-limit

Get package C-state limit (details in 'pkg_cstate_limit'), available package C-state limits (details in 'pkg_cstate_limits'), package C-state limit lock (details in 'pkg_cstate_limit_lock'), and package C-state limit aliases (details in 'pkg_cstate_limit_aliases').

--c1-demotion

Get current setting for C1 demotion (details in 'c1_demotion').

--c1-undemotion

Get current setting for C1 undemotion (details in 'c1_undemotion').

--c1e-autopromote

Get current setting for C1E autopromote (details in 'c1e_autopromote').

--cstate-prewake

Get current setting for C-state prewake (details in 'cstate_prewake').

--idle-driver

Get idle driver (details in 'idle_driver').

--governor

Get idle governor (details in 'governor').

--governors

Get list of available idle governors (details in 'governors').

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

--cpus CPUS

List of CPUs to configure C-States on. 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

List of cores to configure C-States on. 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 '--package' option, because core numbers are per-package

--packages PACKAGES

List of packages to configure C-States on. 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

List of core sibling indices to configure C-States on. The list can include individual core sibling indices or index ranges. For example, core x includes CPUs 3 and 4, '0' would mean CPU 3 and '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 previous example if CPU 3 was offline, then '0' would mean CPU 4.

--override-cpu-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.

--enable [CSTATES]

Comma-separated list of C-states to enable. C-states should be specified by name (e.g., 'C1'). Use 'all' to specify all the available Linux C-states (this is the default). Note, there is a difference between Linux C-states (e.g., 'C6') and hardware C-states (e.g., Core C6 or Package C6 on many Intel platforms). The former is what Linux can request, and on Intel hardware this is usually about various 'mwait' instruction hints. The latter are platform-specific hardware state, entered upon a Linux request.

--disable [CSTATES]

Similar to '--enable', but specifies the list of C-states to disable.

--pkg-cstate-limit [PKG_CSTATE_LIMIT]

Set package C-state limit (details in 'pkg_cstate_limit').

--c1-demotion [C1_DEMOTION]

Enable or disable C1 demotion (details in 'c1_demotion').

--c1-undemotion [C1_UNDEMOTION]

Enable or disable C1 undemotion (details in 'c1_undemotion').

--c1e-autopromote [C1E_AUTOPROMOTE]

Enable or disable C1E autopromote (details in 'c1e_autopromote').

--cstate-prewake [CSTATE_PREWAKE]

Enable or disable C-state prewake (details in 'cstate_prewake').

--governor [GOVERNOR]

Set idle governor (details in 'governor').

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

--cpus CPUS

List of CPUs to save C-state information about. 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

List of cores to save C-state information about. 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 12. Use the special keyword 'all' to specify all cores. This option has to be accompanied by '--package' option, because core numbers are per-package

--packages PACKAGES

List of packages to save C-state information about. 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

List of core sibling indices to save C-state information about. The list can include individual core sibling indices or index ranges. For example, core x includes CPUs 3 and 4, '0' would mean CPU 3 and '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 previous example if CPU 3 was offline, then '0' would mean CPU 4.

-o OUTFILE, --outfile OUTFILE

Name of the file to save the settings to.

Restore C-state settings from a file previously created with the 'pepc cstates 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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pkg_cstate_limit - Package C-state limit

pepc cstates info [--pkg-cstate-limit]

pepc cstates config [--pkg-cstate-limit=<value>]

The deepest package C-state the platform is allowed to enter. MSR_PKG_CST_CONFIG_CONTROL (0xE2) register can be locked, in which case the package C-state limit can only be read, but cannot be modified, please refer to property pkg_cstate_limit_lock.

MSR_PKG_CST_CONFIG_CONTROL (0xE2)

Package C-state limits are documented in Intel SDM, but it describes all the possible package C-states for a CPU model. In practice, however, specific platforms often do not support many of package C-states. For example, Xeons typically do not support anything deeper than PC6.

Refer to 'PCStateConfigCtl.py' for all platforms and bits.

This option has core scope. With the following exceptions: Silvermonts and Airmonts have module scope, Xeon Phis have package scope.

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pkg_cstate_limits - Available package C-state limits

pepc cstates info [--pkg-cstate-limits]

All available package C-state limits.

Hardcoded in 'PCStateConfigCtl.py' for platforms that we have verified.

This option has global scope.

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pkg_cstate_limit_lock - Package C-state limit lock

pepc cstates info [--pkg-cstate-limit-lock]

Whether the package C-state limit can be modified. When 'True', property 'pkg_cstate_limit' is read-only.

MSR_PKG_CST_CONFIG_CONTROL (0xE2) Refer to 'PCStateConfigCtl.py' for all platforms and bits.

This option has package scope.

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pkg_cstate_limit_aliases - Package C-state limit aliases

pepc cstates info [--pkg-cstate-limit-aliases]

Package C-state limit aliases, for example on Ice Lakes 'PC6' is an alias for 'PC6R'.

Hardcoded in 'PCStateConfigCtl.py' for platforms that we have verified.

This option has global scope.

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c1_demotion - C1 demotion

pepc cstates info [--c1-demotion]

pepc cstates config [--c1-demotion=<value>]

Allow or disallow the CPU to demote C6 or C7 requests to C1.

MSR_PKG_CST_CONFIG_CONTROL (0xE2), bit 26.

This option has core scope. With the following exceptions, Silvermonts and Airmonts have module scope, Xeon Phis have package scope.

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c1_demotion - C1 undemotion

pepc cstates info [--c1-undemotion]

pepc cstates config [--c1-undemotion=<value>]

Allow or disallow the CPU to un-demote previously demoted requests back from C1 to C6 or C7.

MSR_PKG_CST_CONFIG_CONTROL (0xE2), bit 28.

This option has core scope. With the following exceptions, Silvermonts and Airmonts have module scope, Xeon Phis have package scope.

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c1e_autopromote - C1E autopromote

pepc cstates info [--c1e-autopromote]

pepc cstates config [--c1e-autopromote=<value>]

When enabled, the CPU automatically converts all C1 requests to C1E requests.

MSR_POWER_CTL (0x1FC), bit 1.

This option has package scope.

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cstate_prewake - C-state prewake

pepc cstates info [--cstate-prewake]

pepc cstates config [--cstate-prewake=<value>]

When enabled, the CPU will start exiting the C6 idle state in advance, prior to the next local APIC timer event.

MSR_POWER_CTL (0x1FC), bit 30.

This option has package scope.

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idle_driver - Idle driver

pepc cstates info [--idle-driver]

Idle driver is responsible for enumerating and requesting the C-states available on the platform.

"/sys/devices/system/cpu/cpuidle/current_governor"

This option has global scope.

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governor - Idle governor

pepc cstates info [--governor]

pepc cstates config [--governor=<value>]

Idle governor decides which C-state to request on an idle CPU.

"/sys/devices/system/cpu/cpuidle/scaling_governor"

This option has global scope.

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governors - Available idle governors

pepc cstates info [--governors]

Idle governors decide which C-state to request on an idle CPU. Different governors implement different selection policy.

"/sys/devices/system/cpu/cpuidle/available_governors"

This property has global scope.