Provided by: powercap-utils_0.1.1-1_amd64 
NAME
rapl-set - set RAPL configurations
SYNPOSIS
rapl-set [OPTION]...
DESCRIPTION
Sets 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-set(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
-p, --package=PACKAGE
The package number (0 by default)
-z, --subzone=SUBZONE
The package subzone number (none by default)
-c, --constraint=CONSTRAINT
The constraint number (none by default)
The following is a zone-level argument (-z/--subzone is optional):
-e, --z-enabled=1|0
Enable/disable a zone
The following constraint-level arguments may be used together and require -c/--constraint (-z/--subzone
is optional):
-l, --c-power-limit=UW
Set constraint power limit
-s, --c-time-window=US
Set constraint time window
EXAMPLES
Note that -p/--package=0 is used by default, allowing for simpler commands on single-socket systems.
rapl-set -e 1
Enable package 0 (implicitly), which is usually named package-0.
rapl-set -p 0 -e 1
Enable package 0 (explicitly).
rapl-set -p 0 -z 1 -e 1
Enable package 0, subzone 1, which is usually the uncore or dram subzone of package-0, depending
on the system.
rapl-set -p 0 -c 1 -l 25000000
Set a power cap of 25 Watts (25000000 uW) on package 0, constraint 1, which is usually the
short_term constraint for package-0.
rapl-set -p 1 -z 0 -c 0 -l 15000000 -s 976
Set a power cap of 15 Watts (15000000 uW) and time window of 976 microseconds on package 1,
subzone 0, constraint 0, which is usually the long_term (and only) constraint for the core subzone
of package-1 (a multi-socket system).
REMARKS
Administrative (root) privileges are usually needed to use rapl-set.
Setting constraint power cap and/or time limit values does not enable or disable a package/subzone - the
-e/--z-enabled flag must be set explicitly.
A package is a zone with constraints. Subzones are a package's child domains, including power planes.
Power units: microwatts (uW)
Time units: microseconds (us)
BUGS
The following are behavioral quirks due to the kernel interface or abnormalities in some hardware. They
are not bugs in rapl-set and should not be reported as such.
The kernel is not guaranteed to accept power limit and time window values exactly as specified. Values
may be rounded due to how they are encoded in Model-Specific Registers. This rounding error is usually
small within normal operating ranges, but can be significant at the extremes.
Some systems may not accept time window values correctly, requiring a system reboot to reset the time
window to the default value.
Values returned by the kernel, e.g., by rapl-info(1), sometimes lose accuracy from the actual stored
value 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 an integer value returned by the kernel may
cause unexpected changes to its stored value due to these rounding problems.
Some systems may not allow disabling package-level zones/constraints.
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. If this matters to the user, it is their responsibility to check before setting
values, e.g., using rapl-info(1).
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
rapl-info(1), powercap-info(1), powercap-set(1)