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CHCPU
Section: System Administration (8) Updated: 202-1-15 Index
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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 state.
if chcpu -g is supported, any disabled CPUs should be deconfigured to inform the hypervisor that these CPUs woncqt 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.
EXIT STATUS
chcpu has the following exit status values:
0
-
success
1
-
failure
64
-
partial success
AUTHORS
COPYRIGHT
Copyright IBM Corp. 2011
SEE ALSO
lscpu(1)
REPORTING BUGS
For bug reports, use the
https://github.com/uti-linux/uti-linux/issues <L>issue tracker
AVAILABILITY
The chcpu command is part of the util-linux package which can be downloaded from
https://www.kernel.org/pub/linux/utils/uti-linux/ <L>Linux Kernel Archive
Index
- NAME
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- SYNOPSIS
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- DESCRIPTION
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- OPTIONS
-
- EXIT STATUS
-
- AUTHORS
-
- COPYRIGHT
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- SEE ALSO
-
- REPORTING BUGS
-
- AVAILABILITY
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