taskset - set or retrieve a process's CPU affinity
[options] mask 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
- is processor #0,
- is processors #0 and #1,
- is processors #0 through #31,
- is processors #1, #4, and #5,
- --cpu-list 0-2,6
- is processors #0, #1, #2, and #6.
returns, it is guaranteed that the given program has been
scheduled to a legal CPU.
- -a, --all-tasks
- Set or retrieve the CPU affinity of all the tasks (threads) for a given
- -c, --cpu-list
- Interpret mask as numerical list of processors instead of a
bitmask. Numbers are separated by commas and may include ranges. For
- -p, --pid
- Operate on an existing PID and do not launch a new task.
- -V, --version
- Display version information and exit.
- -h, --help
- Display help text and exit.
- The default behavior is to run a new command with a given affinity
- 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
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
for a description of the Linux scheduling scheme.
Written by Robert M. Love.
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.
The taskset command is part of the util-linux package and is available from