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  vir-
              tual 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  auto-
              matically detect newly attached CPUs.

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

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

RETURN CODES

       chcpu has the following return codes:

       0      success

       1      failure

       64     partial success

AUTHOR

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

COPYRIGHT

       Copyright IBM Corp. 2011

SEE ALSO

       lscpu(1)

AVAILABILITY

       The  chcpu  command  is  part  of the util-linux package and is available from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils
       /util-linux/>.

util-linux                                                           July 2014                                                            CHCPU(8)