NAME

       taskset - retrieve or set a process's CPU affinity

SYNOPSIS

       taskset [options] mask command [arg]...
       taskset [options] -p [mask] pid

DESCRIPTION

       taskset  is used to set or retrieve the CPU affinity of a running process given its PID or
       to launch a new COMMAND with a given CPU affinity.  CPU affinity is a  scheduler  property
       that  "bonds"  a  process  to a given set of CPUs on the system.  The Linux scheduler will
       honor the given CPU affinity and the process will not run on any other  CPUs.   Note  that
       the  Linux  scheduler  also  supports natural CPU affinity: the scheduler attempts to keep
       processes on the same CPU as  long  as  practical  for  performance  reasons.   Therefore,
       forcing a specific CPU affinity is useful only in certain applications.

       The  CPU  affinity is represented as a bitmask, with the lowest order bit corresponding to
       the first logical CPU and the highest order bit corresponding to  the  last  logical  CPU.
       Not  all  CPUs  may  exist  on  a  given  system but a mask may specify more CPUs than are
       present.  A retrieved mask will reflect only the bits that correspond to  CPUs  physically
       on  the  system.  If an invalid mask is given (i.e., one that corresponds to no valid CPUs
       on the  current  system)  an  error  is  returned.   The  masks  are  typically  given  in
       hexadecimal.  For example,

       0x00000001
              is processor #0

       0x00000003
              is processors #0 and #1

       0xFFFFFFFF
              is all processors (#0 through #31).

       When  taskset  returns,  it  is  guaranteed that the given program has been scheduled to a
       legal CPU.

OPTIONS

       -a, --all-tasks
              Set or retrieve the CPU affinity of all the tasks (threads) for a given PID.

       -p, --pid
              Operate on an existing PID and do not launch a new task.

       -c, --cpu-list
              Specify a numerical list of processors instead  of  a  bitmask.   The  numbers  are
              separated by commas and may include ranges.  For example: 0,5,7,9-11.

       -h, --help
              Display usage information and exit.

       -V, --version
              Display version information and exit.

USAGE

       The default behavior is to run a new command with a given affinity mask:
              taskset mask command [arguments]

       You can also retrieve the CPU affinity of an existing task:
              taskset -p pid

       Or set it:
              taskset -p mask pid

PERMISSIONS

       A  user  must  possess CAP_SYS_NICE to change the CPU affinity of a process.  Any user can
       retrieve the affinity mask.

AUTHOR

       Written by Robert M. Love.

COPYRIGHT

       Copyright © 2004 Robert M. Love
       This is free software; see the source for copying conditions.  There is NO  warranty;  not
       even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       chrt(1), nice(1), renice(1), sched_setaffinity(2), sched_getaffinity(2)

       See sched_setscheduler(2) for a description of the Linux scheduling scheme.

AVAILABILITY

       The   taskset   command   is  part  of  the  util-linux  package  and  is  available  from
       ftp://ftp.kernel.org/pub/linux/utils/util-linux/.