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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXIT STATUS | AUTHORS | COPYRIGHT | SEE ALSO | REPORTING BUGS | AVAILABILITY |
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CHCPU(8) System Administration CHCPU(8)
chcpu - configure CPUs
chcpu -c|-d|-e|-g cpu-list
chcpu -p mode
chcpu -r|-h|-V
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.
-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 deconfigured.
chcpu -g is not supported on IBM z/VM, CPUs are always in a
configured state.
if chcpu -g is supported, any disabled CPUs should be
deconfigured to inform the hypervisor that these CPUs won’t be
used, avoiding potential performance penalties.
-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:
horizontal
The workload is spread across all available CPUs.
vertical
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
Display version and exit.
chcpu has the following exit status values:
0
success
1
failure
64
partial success
Heiko Carstens <heiko.carstens@de.ibm.com>
Copyright IBM Corp. 2011
lscpu(1)
For bug reports, use the issue tracker
<https://github.com/util-linux/util-linux/issues>.
The chcpu command is part of the util-linux package which can be
downloaded from Linux Kernel Archive
<https://www.kernel.org/pub/linux/utils/util-linux/>. This page is
part of the util-linux (a random collection of Linux utilities)
project. Information about the project can be found at
⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
bug report for this manual page, send it to
util-linux@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
2025-08-11. (At that time, the date of the most recent commit that
was found in the repository was 2025-08-05.) 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 man-pages@man7.org
util-linux 2.42-start-521-ec46 2025-01-16 CHCPU(8)
Pages that refer to this page: lscpu(1)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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