Section: Linux User's Manual (1)
Updated: Apr 2003
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taskset - retrieve or set a process's CPU affinity
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,
is processor #0
is processors #0 and #1
is all processors (#0 through #31)
returns, it is guaranteed that the given program has been scheduled to a legal
- -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,
- -h, --help
display usage information and exit
- -V, --version
output version information and exit
- The default behavior is to run a new command with a given affinity mask:
- You can also retrieve the CPU affinity of an existing task:
- Or set it:
A user must possess
to change the CPU affinity of a process. Any user can retrieve the affinity
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.
for a description of the Linux scheduling scheme.
The taskset command is part of the util-linux-ng package and is available from
- SEE ALSO
This document was created by
using the manual pages.