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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | BUGS | AUTHORS | SEE ALSO | REPORTING BUGS | AVAILABILITY |
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LSCPU(1) User Commands LSCPU(1)
lscpu - display information about the CPU architecture
lscpu [options]
lscpu gathers CPU architecture information from sysfs,
/proc/cpuinfo and any applicable architecture-specific libraries
(e.g. librtas on Powerpc). The command output can be optimized for
parsing or for easy readability by humans. The information
includes, for example, the number of CPUs, threads, cores,
sockets, and Non-Uniform Memory Access (NUMA) nodes. There is also
information about the CPU caches and cache sharing, family, model,
bogoMIPS, byte order, and stepping.
The default output formatting on a terminal is subject to change
and may be optimized for better readability. The output for
non-terminals (e.g., pipes) is never affected by this optimization
and it is always in "Field: data\n" format. Use for example "lscpu
| less" to see the default output without optimizations.
In virtualized environments, the CPU architecture information
displayed reflects the configuration of the guest operating system
which is typically different from the physical (host) system. On
architectures that support retrieving physical topology
information, lscpu also displays the number of physical sockets,
chips, cores in the host system.
Options that produce an output table accept an optional list
argument. This list is a comma-separated series of column labels
to limit the table to only the specified columns, arranged in the
specified order. Use --help to see a list of valid column labels.
The labels are case insensitive. Not all columns are supported on
all architectures. If an unsupported column is specified, lscpu
prints the column but does not provide any data for it.
The cache sizes are reported as summary from all CPUs. The
versions before v2.34 reported per-core sizes, but this output was
confusing due to complicated CPUs topology and the way how caches
are shared between CPUs. For more details about caches see
--cache. Since version v2.37 lscpu follows cache IDs as provided
by Linux kernel and it does not always start from zero.
-a, --all
Include lines for online and offline CPUs in the output
(default for -e). This option may only be specified together
with option -e or -p.
-B, --bytes
Print sizes in bytes rather than in human-readable form.
By default, sizes are shown in units that are powers of 1024
bytes. The formal abbreviations for these units (KiB, MiB,
GiB, ...) are further shortened to just their first letter: K,
M, G, ....
-b, --online
Limit the output to online CPUs (default for -p). This option
may only be specified together with option -e or -p.
-C, --caches[=list]
Display details about CPU caches. For details about available
information see --help output.
If the list argument is omitted, all columns for which data is
available are included in the command output.
When specifying the list argument, the option string plus the
equal sign (=) plus the list may not contain any whitespace.
Examples: -C=NAME,ONE-SIZE or --caches=NAME,ONE-SIZE.
The default list of columns may be extended if list is
specified in the format +list (e.g., lscpu -C=+ALLOC-POLICY).
-c, --offline
Limit the output to offline CPUs. This option may only be
specified together with option -e or -p.
-e, --extended[=list]
Display the CPU information in human-readable format.
If the list argument is omitted, the default columns are
included in the command output. The default output is subject
to change.
When specifying the list argument, the option string plus the
equal sign (=) plus the list may not contain any whitespace.
Examples: -e=cpu,node or --extended=cpu,node.
The default list of columns may be extended if list is
specified in the format +list (e.g., lscpu -e=+MHZ).
--hierarchic[=when]
Use subsections in summary output. For backward compatibility,
the default is to use subsections only when output on a
terminal, and to use flattened output on a non-terminal. The
optional argument when can be never, always, or auto. If the
when argument is omitted, it defaults to always.
-J, --json
Use JSON output format for the default summary or extended
output (see --extended). For backward compatibility, JSON
output follows the default summary behavior for non-terminals
(e.g., pipes) where subsections are missing. See also
--hierarchic.
--output-all
Output all available columns. This option must be combined
with either --extended, --parse, or --caches.
-p, --parse[=list]
Optimize the command output for easy parsing.
If the list argument is omitted, the command output is
compatible with earlier versions of lscpu. In this compatible
format, two commas are used to separate CPU cache columns. If
no CPU caches are identified the cache column is omitted. If
the list argument is used, cache columns are separated with a
colon (:).
When specifying the list argument, the option string plus the
equal sign (=) plus the list may not contain any whitespace.
Examples: -p=cpu,online,mhz or --parse=cpu,online,mhz.
The default list of columns may be extended if list is
specified in the format +list (e.g., lscpu -p=+MHZ).
-r, --raw
Produce output in its raw format. This option is only
applicable for the --extended, --parse, and --caches outputs.
-s, --sysroot directory
Gather CPU data for a Linux instance other than the instance
from which the lscpu command is issued. The specified
directory is the system root of the Linux instance to be
inspected.
-x, --hex
Use hexadecimal masks for CPU sets (for example "ff"). The
default is to print the sets in list format (for example 0,1).
Note that before version 2.30 the mask has been printed with
0x prefix.
-y, --physical
Display physical IDs for all columns with topology elements
(core, socket, etc.). Other than logical IDs, which are
assigned by lscpu, physical IDs are platform-specific values
that are provided by the kernel. Physical IDs are not
necessarily unique and they might not be arranged
sequentially. If the kernel could not retrieve a physical ID
for an element lscpu prints the dash (-) character.
The CPU logical numbers are not affected by this option.
-h, --help
Display help text and exit.
-V, --version
Display version and exit.
The basic overview of CPU models is based on heuristics, taking
into account differences such as CPU model names and implementer
IDs. In some (unusual) cases, CPUs may differentiate in flags or
BogoMIPS, but these differences are ignored in the lscpu overview.
Sometimes in Xen Dom0 the kernel reports wrong data.
On virtual hardware the number of cores per socket, etc. can be
wrong.
Cai Qian <qcai@redhat.com>, Karel Zak <kzak@redhat.com>, Heiko
Carstens <heiko.carstens@de.ibm.com>
chcpu(8)
For bug reports, use the issue tracker
<https://github.com/util-linux/util-linux/issues>.
The lscpu command is part of the util-linux package which can be
downloaded from Linux Kernel Archive
<https://www.kernel.org/pub/linux/utils/util-linux/>. This page is
part of the util-linux (a random collection of Linux utilities)
project. Information about the project can be found at
⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
bug report for this manual page, send it to
util-linux@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
2025-08-11. (At that time, the date of the most recent commit that
was found in the repository was 2025-08-05.) If you discover any
rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a
mail to man-pages@man7.org
util-linux 2.42-start-521-ec46 2025-08-09 LSCPU(1)
Pages that refer to this page: sched_setaffinity(2), proc_cpuinfo(5), sched(7), chcpu(8)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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