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.

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/⟩.