chcpu(8) - phpMan

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.

-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.

-V, --version
Display version information and exit.

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

EXIT STATUS
chcpu has the following exit status values:

0
success

1
failure

64
partial success

AUTHORS
Heiko Carstens <heiko.carstens AT de.com>