taskset

Set process CPU affinity

TLDR

Get a running process' CPU affinity by PID

$ taskset -p -c [pid]

Set a running process' CPU affinity by PID

$ taskset -p -c [cpu_id] [pid]

Start a new process with affinity for a single CPU

$ taskset -c [cpu_id] [command]

Start a new process with affinity for multiple non-sequential CPUs

$ taskset -c [cpu_id_1,cpu_id_2,cpu_id_3] [command]

Start a new process with affinity for CPUs 1 through 4

$ taskset -c [1-4] [command]

SYNOPSIS

taskset [options] [mask|list] [pid|command]

taskset retrieves or sets a process's CPU affinity, which controls which CPUs the process can run on. CPU affinity can be specified as a bitmask or a comma-separated list of CPU IDs.
This is useful for performance tuning, isolating processes to specific cores, or testing how software behaves on limited CPU resources.

PARAMETERS

-p, --pid

Operate on an existing PID

-c, --cpu-list

Specify CPUs as a list instead of a bitmask

-a, --all-tasks

Set/get affinity of all tasks (threads)

-h, --help

Display help information

-V, --version

Display version information

CAVEATS

CPU IDs start at 0. Setting affinity may not improve performance and can hurt it if done incorrectly. The kernel may still migrate processes for load balancing unless CPU isolation is configured. Part of the util-linux package.