chcpu(8) — Linux manual page


CHCPU(8)                  System Administration                 CHCPU(8)

NAME         top

       chcpu - configure CPUs

SYNOPSIS         top

       chcpu -c|-d|-e|-g cpu-list

       chcpu -p mode

       chcpu -r|-h|-V

DESCRIPTION         top

       chcpu can modify the state of CPUs. It can enable or disable
       CPUs, scan for new CPUs, change the CPU dispatching mode of the
       underlying hypervisor, and request CPUs from the hypervisor
       (configure) or return CPUs to the hypervisor (deconfigure).

       Some options have a cpu-list argument. Use this argument to
       specify a comma-separated list of CPUs. The list can contain
       individual CPU addresses or ranges of addresses. For example,
       0,5,7,9-11 makes the command applicable to the CPUs with the
       addresses 0, 5, 7, 9, 10, and 11.

OPTIONS         top

       -c, --configure cpu-list
           Configure the specified CPUs. Configuring a CPU means that
           the hypervisor takes a CPU from the CPU pool and assigns it
           to the virtual hardware on which your kernel runs.

       -d, --disable cpu-list
           Disable the specified CPUs. Disabling a CPU means that the
           kernel sets it offline.

       -e, --enable cpu-list
           Enable the specified CPUs. Enabling a CPU means that the
           kernel sets it online. A CPU must be configured, see -c,
           before it can be enabled.

       -g, --deconfigure cpu-list
           Deconfigure the specified CPUs. Deconfiguring a CPU means
           that the hypervisor removes the CPU from the virtual hardware
           on which the Linux instance runs and returns it to the CPU
           pool. A CPU must be offline, see -d, before it can be

           chcpu -g is not supported on IBM z/VM, CPUs are always in a

       -p, --dispatch mode
           Set the CPU dispatching mode (polarization). This option has
           an effect only if your hardware architecture and hypervisor
           support CPU polarization. Available modes are:

               The workload is spread across all available CPUs.

               The workload is concentrated on few CPUs.

       -r, --rescan
           Trigger a rescan of CPUs. After a rescan, the Linux kernel
           recognizes the new CPUs. Use this option on systems that do
           not automatically detect newly attached CPUs.

       -h, --help
           Display help text and exit.

       -V, --version
           Print version and exit.

EXIT STATUS         top

       chcpu has the following exit status values:



           partial success

AUTHORS         top

       Heiko Carstens <>

COPYRIGHT         top

       Copyright IBM Corp. 2011

SEE ALSO         top


REPORTING BUGS         top

       For bug reports, use the issue tracker at

AVAILABILITY         top

       The chcpu command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <>. This page
       is part of the util-linux (a random collection of Linux
       utilities) project. Information about the project can be found at
       ⟨⟩. If you have
       a bug report for this manual page, send it to This page was obtained from the
       project's upstream Git repository
       ⟨git://⟩ on
       2024-06-14. (At that time, the date of the most recent commit
       that was found in the repository was 2024-06-10.) If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page,
       or you have corrections or improvements to the information in
       this COLOPHON (which is not part of the original manual page),
       send a mail to

util-linux 2.41.devel-537-e... 2024-04-04                       CHCPU(8)

Pages that refer to this page: lscpu(1)