set or retrieve a process’s CPU affinity
[options] mask command [argument...]
taskset [options] −p
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.
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
is processor #0,
is processors #0 and #1,
is all processors (#0 through #31).
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.
−c, −−cpu−list numbers
Specify a numerical list of
processors instead of a bitmask. The numbers are
separated by commas and may include ranges. For example:
Operate on an existing PID and
do not launch a new task.
Display version information and
Display help text and exit.
behavior is to run a new command with a given affinity
You can also retrieve the CPU
affinity of an existing task:
Or set it:
taskset −p mask
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.
sched_setscheduler(2) for a description of the Linux
Robert M. Love.
© 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
command is part of the util-linux package and is available