chcpu

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 ad-
       dresses or ranges of addresses.  For example, 0,5,7,9-11 makes the com-
       mand 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 ker-
              nel 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 rec-
              ognizes  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.

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)