200 lines
7.5 KiB
Groff
200 lines
7.5 KiB
Groff
.TH LSCPU 1 "March 2019" "util-linux" "User Commands"
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.SH NAME
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lscpu \- display information about the CPU architecture
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.SH SYNOPSIS
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.B lscpu
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[options]
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.SH DESCRIPTION
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.B lscpu
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gathers CPU architecture information from sysfs, /proc/cpuinfo and any
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applicable architecture-specific libraries (e.g.\& librtas on Powerpc). The
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command output can be optimized for parsing or for easy readability by humans.
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The information includes, for example, the number of CPUs, threads, cores,
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sockets, and Non-Uniform Memory Access (NUMA) nodes. There is also information
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about the CPU caches and cache sharing, family, model, bogoMIPS, byte order,
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and stepping.
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.sp
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In virtualized environments, the CPU architecture information displayed
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reflects the configuration of the guest operating system which is
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typically different from the physical (host) system. On architectures that
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support retrieving physical topology information,
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.B lscpu
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also displays the number of physical sockets, chips, cores in the host system.
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.sp
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Options that result in an output table have a \fIlist\fP argument. Use this
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argument to customize the command output. Specify a comma-separated list of
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column labels to limit the output table to only the specified columns, arranged
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in the specified order. See \fBCOLUMNS\fP for a list of valid column labels. The
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column labels are not case sensitive.
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.sp
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Not all columns are supported on all architectures. If an unsupported column is
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specified, \fBlscpu\fP prints the column but does not provide any data for it.
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.sp
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The default output formatting on terminal maybe optimized for better
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readability. The output for non-terminals (e.g. pipes) is never affected by
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this optimization and it is always in "Field: data\\n" format.
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.SS COLUMNS
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Note that topology elements (core, socket, etc.) use a sequential unique ID
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starting from zero, but CPU logical numbers follow the kernel where there is
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no guarantee of sequential numbering.
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.TP
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.B CPU
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The logical CPU number of a CPU as used by the Linux kernel.
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.TP
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.B CORE
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The logical core number. A core can contain several CPUs.
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.TP
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.B SOCKET
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The logical socket number. A socket can contain several cores.
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.TP
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.B BOOK
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The logical book number. A book can contain several sockets.
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.TP
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.B DRAWER
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The logical drawer number. A drawer can contain several books.
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.TP
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.B NODE
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The logical NUMA node number. A node can contain several drawers.
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.TP
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.B CACHE
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Information about how caches are shared between CPUs.
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.TP
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.B ADDRESS
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The physical address of a CPU.
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.TP
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.B ONLINE
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Indicator that shows whether the Linux instance currently makes use of the CPU.
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.TP
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.B CONFIGURED
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Indicator that shows if the hypervisor has allocated the CPU to the virtual
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hardware on which the Linux instance runs. CPUs that are configured can be set
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online by the Linux instance.
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This column contains data only if your hardware system and hypervisor support
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dynamic CPU resource allocation.
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.TP
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.B POLARIZATION
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This column contains data for Linux instances that run on virtual hardware with
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a hypervisor that can switch the CPU dispatching mode (polarization). The
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polarization can be:
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.RS
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.TP 12
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.B horizontal\fP
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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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.P
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For vertical polarization, the column also shows the degree of concentration,
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high, medium, or low. This column contains data only if your hardware system
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and hypervisor support CPU polarization.
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.RE
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.TP
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.B MAXMHZ
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Maximum megahertz value for the CPU. Useful when \fBlscpu\fP is used as hardware
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inventory information gathering tool. Notice that the megahertz value is
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dynamic, and driven by CPU governor depending on current resource need.
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.TP
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.B MINMHZ
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Minimum megahertz value for the CPU.
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.SH OPTIONS
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.TP
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.BR \-a , " \-\-all"
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Include lines for online and offline CPUs in the output (default for \fB-e\fR).
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This option may only be specified together with option \fB-e\fR or \fB-p\fR.
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.TP
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.BR \-B , " \-\-bytes"
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Print the sizes in bytes rather than in a human-readable format.
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.TP
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.BR \-b , " \-\-online"
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Limit the output to online CPUs (default for \fB-p\fR).
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This option may only be specified together with option \fB-e\fR or \fB-p\fR.
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.TP
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.BR \-C , " \-\-caches" [=\fIlist\fP]
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Display details about CPU caches. For details about available information see \fB\-\-help\fR
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output.
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If the \fIlist\fP argument is omitted, all columns for which data is available
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are included in the command output.
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When specifying the \fIlist\fP argument, the string of option, equal sign (=), and
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\fIlist\fP must not contain any blanks or other whitespace.
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Examples: '\fB-C=NAME,ONE-SIZE\fP' or '\fB--caches=NAME,ONE-SIZE\fP'.
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.TP
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.BR \-c , " \-\-offline"
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Limit the output to offline CPUs.
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This option may only be specified together with option \fB-e\fR or \fB-p\fR.
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.TP
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.BR \-e , " \-\-extended" [=\fIlist\fP]
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Display the CPU information in human-readable format.
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If the \fIlist\fP argument is omitted, all columns for which data is available
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are included in the command output.
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When specifying the \fIlist\fP argument, the string of option, equal sign (=), and
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\fIlist\fP must not contain any blanks or other whitespace.
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Examples: '\fB-e=cpu,node\fP' or '\fB--extended=cpu,node\fP'.
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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 \-J , " \-\-json"
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Use JSON output format for the default summary or extended output (see \fB\-\-extended\fP).
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.TP
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.BR \-p , " \-\-parse" [=\fIlist\fP]
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Optimize the command output for easy parsing.
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If the \fIlist\fP argument is omitted, the command output is compatible with earlier
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versions of \fBlscpu\fP. In this compatible format, two commas are used to separate
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CPU cache columns. If no CPU caches are identified the cache column is omitted.
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.br
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If the \fIlist\fP argument is used, cache columns are separated with a colon (:).
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When specifying the \fIlist\fP argument, the string of option, equal sign (=), and
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\fIlist\fP must not contain any blanks or other whitespace.
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Examples: '\fB-p=cpu,node\fP' or '\fB--parse=cpu,node\fP'.
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.TP
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.BR \-s , " \-\-sysroot " \fIdirectory\fP
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Gather CPU data for a Linux instance other than the instance from which the
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\fBlscpu\fP command is issued. The specified \fIdirectory\fP is the system root
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of the Linux instance to be inspected.
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.TP
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.BR \-x , " \-\-hex"
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Use hexadecimal masks for CPU sets (for example "ff"). The default is to print
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the sets in list format (for example 0,1). Note that before version 2.30 the mask
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has been printed with 0x prefix.
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.TP
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.BR \-y , " \-\-physical"
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Display physical IDs for all columns with topology elements (core, socket, etc.).
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Other than logical IDs, which are assigned by \fBlscpu\fP, physical IDs are
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platform-specific values that are provided by the kernel. Physical IDs are not
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necessarily unique and they might not be arranged sequentially.
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If the kernel could not retrieve a physical ID for an element \fBlscpu\fP prints
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the dash (-) character.
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The CPU logical numbers are not affected by this option.
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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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.TP
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.B \-\-output\-all
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Output all available columns. This option must be combined with either
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.BR \-\-extended ", " \-\-parse " or " \-\-caches .
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.SH BUGS
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The basic overview of CPU family, model, etc. is always based on the first
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CPU only.
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Sometimes in Xen Dom0 the kernel reports wrong data.
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On virtual hardware the number of cores per socket, etc. can be wrong.
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.SH AUTHOR
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.nf
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Cai Qian <qcai@redhat.com>
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Karel Zak <kzak@redhat.com>
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Heiko Carstens <heiko.carstens@de.ibm.com>
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.fi
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.SH "SEE ALSO"
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.BR chcpu (8)
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.SH AVAILABILITY
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The lscpu command is part of the util-linux package and is available from
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https://www.kernel.org/pub/linux/utils/util-linux/.
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