cpulist.py -- display CPU affinity information as ASCII art.

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Summary

With this Python script, you get a visual display of the layout of physical CPUs, CPU cores and processor ID's. It is straightforward to see which processors/cores are siblings.

This could be useful, for example, for confining a process to CPU cores identified by their numeric IDs with the taskset -c command.

Requirements

This script runs on Linux by reading the file /proc/cpuinfo. The format of that file depends on the architecture, and this script seems to work for Intel x86/x86_64 systems. It is probably straightforward to add support for other systems.

Example

Example output from a machine with 4 set of CPUs, each with 10 cores, and each core capable of running 2 threads (Intel HT):

--*-+-physical id: 0-+-core id: 0-+-processor: 0
    |                |            `-processor: 40
    |                |-core id: 1-+-processor: 4
    |                |            `-processor: 44
    |                |-core id: 2-+-processor: 8
    |                |            `-processor: 48
    |                |-core id: 8-+-processor: 12
    |                |            `-processor: 52
    |                |-core id: 9-+-processor: 16
    |                |            `-processor: 56
    |                |-core id: 16-+-processor: 20
    |                |             `-processor: 60
    |                |-core id: 17-+-processor: 24
    |                |             `-processor: 64
    |                |-core id: 18-+-processor: 28
    |                |             `-processor: 68
    |                |-core id: 24-+-processor: 32
    |                |             `-processor: 72
    |                `-core id: 25-+-processor: 36
    |                              `-processor: 76
    |-physical id: 1-+-core id: 0-+-processor: 1
    |                |            `-processor: 41
    |                |-core id: 1-+-processor: 5
    |                |            `-processor: 45
    |                |-core id: 2-+-processor: 9
    |                |            `-processor: 49
    |                |-core id: 8-+-processor: 13
    |                |            `-processor: 53
    |                |-core id: 9-+-processor: 17
    |                |            `-processor: 57
    |                |-core id: 16-+-processor: 21
    |                |             `-processor: 61
    |                |-core id: 17-+-processor: 25
    |                |             `-processor: 65
    |                |-core id: 18-+-processor: 29
    |                |             `-processor: 69
    |                |-core id: 24-+-processor: 33
    |                |             `-processor: 73
    |                `-core id: 25-+-processor: 37
    |                              `-processor: 77
    |-physical id: 2-+-core id: 0-+-processor: 2
    |                |            `-processor: 42
    |                |-core id: 1-+-processor: 6
    |                |            `-processor: 46
    |                |-core id: 2-+-processor: 10
    |                |            `-processor: 50
    |                |-core id: 8-+-processor: 14
    |                |            `-processor: 54
    |                |-core id: 9-+-processor: 18
    |                |            `-processor: 58
    |                |-core id: 16-+-processor: 22
    |                |             `-processor: 62
    |                |-core id: 17-+-processor: 26
    |                |             `-processor: 66
    |                |-core id: 18-+-processor: 30
    |                |             `-processor: 70
    |                |-core id: 24-+-processor: 34
    |                |             `-processor: 74
    |                `-core id: 25-+-processor: 38
    |                              `-processor: 78
    `-physical id: 3-+-core id: 0-+-processor: 3
                     |            `-processor: 43
                     |-core id: 1-+-processor: 7
                     |            `-processor: 47
                     |-core id: 2-+-processor: 11
                     |            `-processor: 51
                     |-core id: 8-+-processor: 15
                     |            `-processor: 55
                     |-core id: 9-+-processor: 19
                     |            `-processor: 59
                     |-core id: 16-+-processor: 23
                     |             `-processor: 63
                     |-core id: 17-+-processor: 27
                     |             `-processor: 67
                     |-core id: 18-+-processor: 31
                     |             `-processor: 71
                     |-core id: 24-+-processor: 35
                     |             `-processor: 75
                     `-core id: 25-+-processor: 39
                                   `-processor: 79