97 lines
2.5 KiB
Groff
97 lines
2.5 KiB
Groff
.TH CHCPU "8" "June 2012" Linux "User Manuals"
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.SH NAME
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chcpu \- configure CPUs
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.SH SYNOPSIS
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chcpu
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[\-e] [\-d] [\-c] [\-g]
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cpu-list
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.br
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chcpu [\-p] mode
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.br
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chcpu
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\-r
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.br
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chcpu [\-h] [\-V]
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.br
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.SH DESCRIPTION
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.B chcpu
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can modify the state of CPUs. It can enable or disable CPUs, scan for new
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CPUs, change the CPU dispatching
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.I mode
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of the underlying hypervisor, and request CPUs from the hypervisor
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(configure) or return CPUs to the hypervisor (deconfigure).
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.PP
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Some options have a
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.I cpu-list
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argument. Use this argument to specify a comma-separated list of CPUs. The
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list can contain individual CPU addresses or ranges of addresses. For
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example,
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.B 0,5,7,9-11
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makes the command applicable to the CPUs with the addresses 0, 5, 7, 9, 10,
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and 11.
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.SH OPTIONS
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.TP
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.BR \-r , " \-\-rescan"
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Trigger a rescan of CPUs. Use this option on systems that do not
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automatically detect newly attached CPUs. The Linux kernel then recognizes
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the new CPUs.
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.TP
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.BR \-c , " \-\-configure " \fIcpu-list\fP
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Configure all specified CPUs. Configuring a CPU means that the hypervisor
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takes a CPU from the CPU pool and assigns it to the virtual hardware on which
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your kernel runs.
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.TP
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.BR \-e , " \-\-enable " \fIcpu-list\fP
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Enable all specified CPUs. Enabling a CPU means that the kernel sets it
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online. A CPU must be configured, see
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.BR -c ,
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before it can be enabled.
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.TP
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.BR \-p , " \-\-dispatch " \fImode\fP
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Set the CPU dispatching
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.I mode
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(polarization). This option has an effect only if your hardware architecture
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and hypervisor support CPU polarization. Available
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.I modes
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are:
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.RS 14
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.TP 12
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.PD 0
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.B horizontal
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The workload is spread across all available CPUs.
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.TP 12
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.B vertical
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The workload is concentrated on few CPUs.
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.RE
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.PD 1
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.TP
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.BR \-d , " \-\-disable " \fIcpu-list\fP
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Disable all specified CPUs. Disabling a CPU means that the kernel sets it
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offline.
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.TP
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.BR \-g , " \-\-deconfigure " \fIcpu-list\fP
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Deconfigure all specified CPUs. Deconfiguring a CPU means that the
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hypervisor removes the CPU from the virtual hardware on which the Linux
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instance runs and returns it to the CPU pool. A CPU must be offline, see
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\-d, before it can be deconfigured.
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.TP
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.BR \-h , " \-\-help"
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Display help text and exit.
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.TP
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.BR \-V , " \-\-version"
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Display version information and exit.
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.SH AUTHOR
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.MT heiko.carstens@de.ibm.com
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Heiko Carstens
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.ME
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.SH COPYRIGHT
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Copyright IBM Corp. 2011
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.br
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.SH "SEE ALSO"
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.BR lscpu (1)
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.SH AVAILABILITY
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The chcpu command is part of the util-linux package and is available from
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.UR ftp://\:ftp.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
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Linux Kernel Archive
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.UE .
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