CHCPU(8) User Manuals CHCPU(8)NAME
chcpu - configure CPUs
chcpu [-e] [-d] [-c] [-g] cpu-list
chcpu [-p] mode
chcpu [-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
Trigger a rescan of CPUs. Use this option on systems that do
not automatically detect newly attached CPUs. The Linux kernel
then recognizes the new CPUs.
-c, --configure cpu-list
Configure all 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.
-e, --enable cpu-list
Enable all specified CPUs. Enabling a CPU means that the kernel
sets it online. A CPU must be configured, see -c, before it can
-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
vertical The workload is concentrated on few CPUs.
-d, --disable cpu-list
Disable all specified CPUs. Disabling a CPU means that the ker‐
nel sets it offline.
-g, --deconfigure cpu-list
Deconfigure all 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.
Display help information and exit.
Display version information and exit.
Heiko Carstens ⟨firstname.lastname@example.org⟩
Copyright IBM Corp. 2011
The chcpu command is part of the util-linux package and is available
from Linux Kernel Archive ⟨ftp://ftp.kernel.org/pub/linux/utils/util-
Linux June 2012 CHCPU(8)