1TASKSET(1) Linux User's Manual TASKSET(1)
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6 taskset - retrieve or set a process's CPU affinity
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9 taskset [options] mask command [arg]...
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.
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23 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 are typically given in hexadecimal. For example,
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32 0x00000001
33 is processor #0
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35 0x00000003
36 is processors #0 and #1
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38 0xFFFFFFFF
39 is all processors (#0 through #31)
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41 When taskset returns, it is guaranteed that the given program has been
42 scheduled to a legal CPU.
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45 -p, --pid
46 operate on an existing PID and not launch a new task
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48 -c, --cpu-list
49 specify a numerical list of processors instead of a bitmask.
50 The list may contain multiple items, separated by comma, and
51 ranges. For example, 0,5,7,9-11.
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53 -h, --help
54 display usage information and exit
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56 -V, --version
57 output version information and exit
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60 The default behavior is to run a new command with a given affinity
61 mask:
62 taskset mask command [arguments]
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64 You can also retrieve the CPU affinity of an existing task:
65 taskset -p pid
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67 Or set it:
68 taskset -p mask pid
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71 A user must possess CAP_SYS_NICE to change the CPU affinity of a
72 process. Any user can retrieve the affinity mask.
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75 Written by Robert M. Love.
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78 Copyright © 2004 Robert M. Love
79 This is free software; see the source for copying conditions. There is
80 NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
81 PURPOSE.
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84 chrt(1), nice(1), renice(1), sched_setaffinity(2), sched_getaffinity(2)
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86 See sched_setscheduler(2) for a description of the Linux scheduling
87 scheme.
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90 The taskset command is part of the util-linux-ng package and is avail‐
91 able from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
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95schedutils Apr 2003 TASKSET(1)