#Bash 的 taskset 命令

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 affinity of some
       processes like kernel per-CPU threads cannot be set.

       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,

       FFFFFFFF
           is processors #0 through #31,

       0x32
           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

       When a cpu-list is specified for an existing process, the -p and -c
       options must be grouped together:
           taskset -pc cpu-list pid

       The --cpu-list form is applicable only for launching new commands:
           taskset --cpu-list cpu-list command

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.

RETURN VALUE
       taskset returns 0 in its affinity-getting mode as long as the provided
       PID exists.

       taskset returns 0 in its affinity-setting mode as long as the
       underlying sched_setaffinity(2) system call does. The success of the
       command does not guarantee that the specified thread has actually
       migrated to the indicated CPU(s), but only that the thread will not
       migrate to a CPU outside the new affinity mask. For example, the
       affinity of the kernel thread kswapd can be set, but the thread may not
       immediately migrate and is not guaranteed to ever do so:

       $ ps ax -o comm,psr,pid | grep kswapd
       kswapd0           4      82
       $ sudo taskset -p 1 82
       pid 82’s current affinity mask: 1
       pid 82’s new affinity mask: 1
       $ echo $?
       0
       $ ps ax -o comm,psr,pid | grep kswapd
       kswapd0           4      82
       $ taskset -p 82
       pid 82’s current affinity mask: 1

       In contrast, when the user specifies an illegal affinity, taskset will
       print an error and return 1:

       $ ps ax -o comm,psr,pid | grep ksoftirqd/0
       ksoftirqd/0       0      14
       $ sudo taskset -p 1 14
       pid 14’s current affinity mask: 1
       taskset: failed to set pid 14’s affinity: Invalid argument
       $ echo $?
       1

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 2.39.3                 2023-11-21                        TASKSET(1)