DOKK / manpages / debian 10 / powercap-utils / rapl-info.1.en
rapl-info(1) rapl-info rapl-info(1)

rapl-info - get RAPL configurations

rapl-info [OPTION]...

Prints out Intel Running Average Power Limit (RAPL) configurations.

Since RAPL does not implement all capabilities defined in the powercap interface, only a subset of the options from powercap-info(1) are available. Additionally, the -p and -z options are different.

This software requires an Intel processor (Sandy Bridge or newer), Linux kernel 3.13 or newer compiled with CONFIG_POWERCAP and CONFIG_INTEL_RAPL enabled, and the intel_rapl kernel module to be loaded.

Prints out the help screen
Print errors when files are not available
The package number (none by default; 0 by default if using -z/--subzone and/or -c/--constraint). Ending with a colon prevents output for subzones. E.g., for package 0, but not subzones:
-p 0:
The package subzone number (none by default)
The constraint number (none by default)
Print the number of packages found, or the number of subzones found if -p/--package is set

The following are zone-level arguments (-z/--subzone is optional):

Print zone energy counter
Print zone maximum energy counter range
Print zone enable/disabled status
Print zone name

The following are constraint-level arguments and require -c/--constraint (-z/--subzone is optional):

Print constraint power limit
Print constraint time window
Print constraint maximum allowed power
Print constraint name

Note that -p/--package=0 is used by default when also specifying -z/--subzone and/or -c/--constraint, allowing for simpler commands on single-socket systems.

Print all RAPL zones.
Print only package 0, which is usually named package-0.
Print package 0, subzone 1, which is usually the uncore or dram subzone of package-0, depending on the system.
Print package 0, constraint 1, which is usually the short_term constraint for package-0.
Print the energy counter for package 0, which is usually named package-0.
Print the power limit for package 1, subzone 0, constraint 0, which is usually the long_term constraint for the core subzone of package-1 (a multi-socket system).

A package is a zone with constraints. Subzones are a package's child domains, including power planes.

If no subzone/constraint-specific outputs are requested, all available zones and constraints will be shown.

Energy units: microjoules (uJ)
Power units: microwatts (uW)
Time units: microseconds (us)

The following are behavioral quirks due to the kernel interface or abnormalities in some hardware. They are not bugs in rapl-info and should not be reported as such.

Values returned by the kernel sometimes lose accuracy from the actual values stored in Model-Specific Registers due to integer rounding. For example, the kernel may return a time window value of 7812 us, when in fact the actual stored value is 7812.5 us. Writing back a value returned by the kernel, e.g., using rapl-set(1), may cause unexpected changes to its value due to these rounding problems.

On some systems, the constraint max_power_uw file, e.g., constraint_0_max_power_uw, is known to receive an ENODATA (No data available) error from the kernel for subzones. So even though the file exists, a value may not be printed for it.

It is possible for packages on multi-socket systems to be indexed out of order by the kernel. For example, the package at index 0 (-p 0) could actually be named package-1 while the package at index 1 (-p 1) is named package-0.

Report bugs upstream at <https://github.com/powercap/powercap>

/sys/devices/virtual/powercap/intel-rapl/*


/sys/class/powercap/intel-rapl/*

Connor Imes <connor.k.imes@gmail.com>

rapl-set(1), powercap-info(1), powercap-set(1)

2017-09-20 powercap