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)