CHCPU(8)							   User Manuals 							  CHCPU(8)

NAME

       chcpu - configure CPUs

SYNOPSIS

       chcpu [-e] [-d] [-c] [-g] cpu-list
       chcpu [-p] mode
       chcpu -r
       chcpu [-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

       -r, --rescan
	      Trigger a rescan of CPUs.  Use this option on systems that do not automatically detect newly attached CPUs.  The Linux  kernel  then
	      recognizes the new CPUs.

       -c, --configure cpu-list
	      Configure  all 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.

       -e, --enable cpu-list
	      Enable all specified CPUs.  Enabling a CPU means that the kernel sets it online.	A CPU must be configured, see -c, before it can be
	      enabled.

       -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.

       -d, --disable cpu-list
	      Disable all specified CPUs.  Disabling a CPU means that the kernel sets it offline.

       -g, --deconfigure cpu-list
	      Deconfigure all 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.

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

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

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 <ftp://ftp.kernel.org/pub/linux/utils/util-
       linux/>.

Linux								     June 2012								  CHCPU(8)