retrieve or set a process’s CPU affinity
see also :
chrt - nice - renice
taskset [options] -p
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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
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
taskset returns, it is guaranteed that the given
program has been scheduled to a legal CPU.
Set or retrieve the CPU
affinity of all the tasks (threads) for a given PID.
Operate on an existing PID and
do not launch a new task.
Specify a numerical list of
processors instead of a bitmask. The numbers are separated
by commas and may include ranges. For example:
Display usage information and
Display version information and
The taskset command is part of the util-linux package and is
available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
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.
A user must possess CAP_SYS_NICE to change the CPU
affinity of a process. Any user can retrieve the affinity mask.
The default behavior is to run a new command with a given
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
nice , renice ,
sched_setscheduler for a description of the Linux
Robert M. Love.