CHCPU(8)                     System Administration                    CHCPU(8)

       chcpu - configure CPUs

       chcpu -c|-d|-e|-g cpu-list
       chcpu -p mode
       chcpu -r|-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

       -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
                     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.

       chcpu has the following return codes:

       0      success

       1      failure

       64     partial success

       Heiko Carstens <>

       Copyright IBM Corp. 2011


       The  chcpu  command  is part of the util-linux package and is available
       from Linux Kernel Archive <

util-linux                         July 2014                          CHCPU(8)
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