1TASKSET(1) User Commands TASKSET(1)
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6 taskset - set or retrieve a process's CPU affinity
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9 taskset [options] mask command [argument...]
10 taskset [options] -p [mask] pid
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13 taskset is used to set or retrieve the CPU affinity of a running
14 process given its pid, or to launch a new command with a given CPU
15 affinity. CPU affinity is a scheduler property that "bonds" a process
16 to a given set of CPUs on the system. The Linux scheduler will honor
17 the given CPU affinity and the process will not run on any other CPUs.
18 Note that the Linux scheduler also supports natural CPU affinity: the
19 scheduler attempts to keep processes on the same CPU as long as practi‐
20 cal for performance reasons. Therefore, forcing a specific CPU affin‐
21 ity is useful only in certain applications.
22 The CPU affinity is represented as a bitmask, with the lowest order bit
24 corresponding to the first logical CPU and the highest order bit corre‐
25 sponding to the last logical CPU. Not all CPUs may exist on a given
26 system but a mask may specify more CPUs than are present. A retrieved
27 mask will reflect only the bits that correspond to CPUs physically on
28 the system. If an invalid mask is given (i.e., one that corresponds to
29 no valid CPUs on the current system) an error is returned. The masks
30 may be specified in hexadecimal (with or without a leading "0x"), or as
31 a CPU list with the --cpu-list option. For example,
32 0x00000001 is processor #0,
34 0x00000003 is processors #0 and #1,
36 0xFFFFFFFF is processors #0 through #31,
38 32 is processors #1, #4, and #5,
40 --cpu-list 0-2,6
42 is processors #0, #1, #2, and #6.
43 --cpu-list 0-10:2
45 is processors #0, #2, #4, #6, #8 and #10. The suffix
46 ":N" specifies stride in the range, for example 0-10:3
47 is interpreted as 0,3,6,9 list.
48 When taskset returns, it is guaranteed that the given program has been
50 scheduled to a legal CPU.
51
53 -a, --all-tasks
54 Set or retrieve the CPU affinity of all the tasks (threads) for
55 a given PID.
56 -c, --cpu-list
58 Interpret mask as numerical list of processors instead of a bit‐
59 mask. Numbers are separated by commas and may include ranges.
60 For example: 0,5,8-11.
61 -p, --pid
63 Operate on an existing PID and do not launch a new task.
64 -V, --version
66 Display version information and exit.
67 -h, --help
69 Display help text and exit.
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72 The default behavior is to run a new command with a given affinity
73 mask:
74 taskset mask command [arguments]
75 You can also retrieve the CPU affinity of an existing task:
77 taskset -p pid
78 Or set it:
80 taskset -p mask pid
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83 A user can change the CPU affinity of a process belonging to the same
84 user. A user must possess CAP_SYS_NICE to change the CPU affinity of a
85 process belonging to another user. A user can retrieve the affinity
86 mask of any process.
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89 chrt(1), nice(1), renice(1), sched_getaffinity(2), sched_setaffinity(2)
90 See sched(7) for a description of the Linux scheduling scheme.
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94 Written by Robert M. Love.
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97 Copyright © 2004 Robert M. Love. This is free software; see the source
98 for copying conditions. There is NO warranty; not even for MER‐
99 CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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102 The taskset command is part of the util-linux package and is available
103 from https://www.kernel.org/pub/linux/utils/util-linux/.
104util-linux August 2014 TASKSET(1)