1CHCPU(8)                     System Administration                    CHCPU(8)
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NAME

6       chcpu - configure CPUs
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SYNOPSIS

9       chcpu -c|-d|-e|-g cpu-list
10       chcpu -p mode
11       chcpu -r|-h|-V
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DESCRIPTION

14       chcpu  can  modify  the  state of CPUs.  It can enable or disable CPUs,
15       scan for new CPUs, change the CPU dispatching mode  of  the  underlying
16       hypervisor,  and request CPUs from the hypervisor (configure) or return
17       CPUs to the hypervisor (deconfigure).
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19       Some options have a cpu-list argument.  Use this argument to specify  a
20       comma-separated  list  of  CPUs.   The  list can contain individual CPU
21       addresses or ranges of addresses.  For example,  0,5,7,9-11  makes  the
22       command  applicable  to the CPUs with the addresses 0, 5, 7, 9, 10, and
23       11.
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OPTIONS

26       -c, --configure cpu-list
27              Configure the specified CPUs.  Configuring a CPU means that  the
28              hypervisor  takes  a CPU from the CPU pool and assigns it to the
29              virtual hardware on which your kernel runs.
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31       -d, --disable cpu-list
32              Disable the specified CPUs.  Disabling a CPU means that the ker‐
33              nel sets it offline.
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35       -e, --enable cpu-list
36              Enable the specified CPUs.  Enabling a CPU means that the kernel
37              sets it online.  A CPU must be configured, see -c, before it can
38              be enabled.
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40       -g, --deconfigure cpu-list
41              Deconfigure  the specified CPUs.  Deconfiguring a CPU means that
42              the hypervisor removes the CPU  from  the  virtual  hardware  on
43              which the Linux instance runs and returns it to the CPU pool.  A
44              CPU must be offline, see -d, before it can be deconfigured.
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46       -p, --dispatch mode
47              Set the CPU dispatching mode (polarization).  This option has an
48              effect only if your hardware architecture and hypervisor support
49              CPU polarization.  Available modes are:
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51                     horizontal  The workload is spread across  all  available
52                                 CPUs.
53                     vertical    The workload is concentrated on few CPUs.
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55       -r, --rescan
56              Trigger a rescan of CPUs.  After a rescan, the Linux kernel rec‐
57              ognizes the new CPUs.  Use this option on systems  that  do  not
58              automatically detect newly attached CPUs.
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60       -V, --version
61              Display version information and exit.
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63       -h, --help
64              Display help text and exit.
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RETURN CODES

68       chcpu has the following return codes:
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70       0      success
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72       1      failure
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74       64     partial success
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AUTHOR

77       Heiko Carstens ⟨heiko.carstens@de.ibm.com⟩
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80       Copyright IBM Corp. 2011
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SEE ALSO

83       lscpu(1)
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AVAILABILITY

86       The  chcpu  command  is part of the util-linux package and is available
87       from Linux Kernel Archive ⟨https://www.kernel.org/pub/linux/utils/util-
88       linux/⟩.
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92util-linux                         July 2014                          CHCPU(8)
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