CHCPU(8)                     System Administration                    CHCPU(8)

NAME
       chcpu - configure CPUs

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

       chcpu -p mode

       chcpu -r|-h|-V

DESCRIPTION
       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
       -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.

       -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
           Print version and exit.

EXIT STATUS
       chcpu has the following exit status values:

       0
           success

       1
           failure

       64
           partial success

AUTHORS
       Heiko Carstens <heiko.carstens@de.ibm.com>

COPYRIGHT
       Copyright IBM Corp. 2011

SEE ALSO
       lscpu(1)

REPORTING BUGS
       For bug reports, use the issue tracker at
       <https://github.com/util-linux/util-linux/issues>.

AVAILABILITY
       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/>.

util-linux 2.40                   2024-04-06                          CHCPU(8)