NAME¶

SYNPOSIS¶

DESCRIPTION¶

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.

OPTIONS¶

-h, --help

Prints out the help screen

-v, --verbose

Print errors when files are not available

-p, --package=PACKAGE

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:

-z, --subzone=SUBZONE

The package subzone number (none by default)

-c, --constraint=CONSTRAINT

The constraint number (none by default)

All remaining options below are mutually exclusive:

-n, --nzones

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):

-j, --z-energy

Print zone energy counter

-J, --z-max-energy-range

Print zone maximum energy counter range

-e, --z-enabled

Print zone enable/disabled status

-x, --z-name

Print zone name

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

-l, --c-power-limit

Print constraint power limit

-s, --c-time-window

Print constraint time window

-U, --c-max-power

Print constraint maximum allowed power

-y, --c-name

Print constraint name

EXAMPLES¶

rapl-info

Print all RAPL zones.

rapl-info -p 0

Print only package 0, which is usually named package-0.

rapl-info -p 0 -z 1

Print package 0, subzone 1, which is usually the uncore or dram subzone of package-0, depending on the system.

rapl-info -p 0 -c 1

Print package 0, constraint 1, which is usually the short_term constraint for package-0.

rapl-info -p 0 -j

Print the energy counter for package 0, which is usually named package-0.

rapl-info -p 1 -z 0 -c 0 -l

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).

REMARKS¶

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)

BUGS¶

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>

FILES¶

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


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

AUTHORS¶

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

SEE ALSO¶