TASKSET(1) User Commands TASKSET(1)
NAME
taskset - set or retrieve a process's CPU affinity
SYNOPSIS
taskset [options] mask command [argument...]
taskset [options] -p [mask] pid
DESCRIPTION
The taskset command 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 may be specified in hexadecimal (with or without a
leading "0x"), or as a CPU list with the --cpu-list option. For
example,
0x00000001
is processor #0,
0x00000003
is processors #0 and #1,
0xFFFFFFFF
is processors #0 through #31,
32
is processors #1, #4, and #5,
--cpu-list 0-2,6
is processors #0, #1, #2, and #6.
--cpu-list 0-10:2
is processors #0, #2, #4, #6, #8 and #10. The suffix ":N" specifies
stride in the range, for example 0-10:3 is interpreted as 0,3,6,9
list.
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.
-c, --cpu-list
Interpret mask as numerical list of processors instead of a
bitmask. Numbers are separated by commas and may include ranges.
For example: 0,5,8-11.
-p, --pid
Operate on an existing PID and do not launch a new task.
-h, --help
Display help text and exit.
-V, --version
Print version 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 can change the CPU affinity of a process belonging to the same
user. A user must possess CAP_SYS_NICE to change the CPU affinity of a
process belonging to another user. A user can retrieve the affinity
mask of any process.
AUTHORS
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_getaffinity(2), sched_setaffinity(2)
See sched(7) for a description of the Linux scheduling scheme.
REPORTING BUGS
For bug reports, use the issue tracker at
https://github.com/util-linux/util-linux/issues.
AVAILABILITY
The taskset command is part of the util-linux package which can be
downloaded from Linux Kernel Archive
<https://www.kernel.org/pub/linux/utils/util-linux/>.
util-linux 2.38.1 2022-05-11 TASKSET(1)
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