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TASKSET(1)			       Linux User's Manual			       TASKSET(1)

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,  forc-
       ing 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	hexadeci-
       mal.  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
       -p, --pid
	      operate on an existing PID and not launch a new task

       -c, --cpu-list
	      specify a numerical list of processors instead of a bitmask.  The list may  contain
	      multiple items, separated by comma, and ranges.  For example, 0,5,7,9-11.

       -h, --help
	      display usage information and exit

       -V, --version
	      output 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 (C) 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.ker-
       nel.org/pub/linux/utils/util-linux/.

schedutils				     Apr 2003				       TASKSET(1)
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