lscpu Man page

LSCPU(1) User Commands LSCPU(1)

NAME

lscpu – display information about the CPU architecture

SYNOPSIS

lscpu [-a|-b|-c] [-x] [-s directory] [-e[=list]|-p[=list]] lscpu -h|-V

DESCRIPTION

lscpu gathers CPU architecture information from sysfs and
/proc/cpuinfo. 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.

Options that result in an output table have a list argument. Use this
argument to customize the command output. Specify a comma-separated
list of column labels to limit the output table to only the specified
columns, arranged in the specified order. See COLUMNS for a list of
valid column labels. The column labels are not case sensitive.

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.

COLUMNS
Note that topology elements (core, socket, etc.) use sequential unique
ID starting from zero, but CPU logical numbers follow kernel where is
no guarantee of the sequential numbering.

CPU The logical CPU number of a CPU as used by the Linux kernel.

CORE The logical core number. A core can contain several CPUs.

SOCKET The logical socket number. A socket can contain several cores.

BOOK The logical book number. A book can contain several sockets.

NODE The logical NUMA node number. A node may contain several books.

CACHE Information about how caches are shared between CPUs.

ADDRESS
The physical address of a CPU.

ONLINE Indicator that shows whether the Linux instance currently makes
use of the CPU.

CONFIGURED
Indicator that shows if the hypervisor has allocated the CPU to
the virtual hardware on which the Linux instance runs. CPUs
that are configured can be set online by the Linux instance.
This column contains data only if your hardware system and
hypervisor support dynamic CPU resource allocation.

POLARIZATION
This column contains data for Linux instances that run on vir‐
tual hardware with a hypervisor that can switch the CPU dis‐
patching mode (polarization). The polarization can be:

horizontal The workload is spread across all available CPUs.

vertical The workload is concentrated on few CPUs.

For vertical polarization, the column also shows the degree of
concentration, high, medium, or low. This column contains data
only if your hardware system and hypervisor support CPU polar‐
ization.

MMHZ Maximum megaherz value for the cpu. Useful when lscpu is
used as hardware inventory information gathering tool.
Notice that the megahertz value is dynamic, and driven by
CPU governor depending on current resource need.

OPTIONS

-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, –online
Limit the output to online CPUs (default for -p). This option
may only be specified together with option -e or -p.

-c, –offline
Limit the output to offline CPUs. This option may only be spec‐
ified together with option -e or -p.

-e, –extended[=list] Display the CPU information in human readable format.

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 string of option, equal
sign (=), and list must not contain any blanks or other white‐
space. Examples: ‘-e=cpu,node’ or ‘–extended=cpu,node’.

-h, –help
Display help text and exit.

-p, –parse[=list] Optimize the command output for easy parsing.

If the list argument is omitted, the command output is compati‐
ble 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 string of option, equal
sign (=), and list must not contain any blanks or other white‐
space. Examples: ‘-p=cpu,node’ or ‘–parse=cpu,node’.

-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 0x3). The
default is to print the sets in list format (for example 0,1).

-V, –version
Display version information and exit.

BUGS

The basic overview of CPU family, model, etc. is always based on the
first CPU only.

Sometimes in Xen Dom0 the kernel reports wrong data.

On virtual hardware the number of cores per socket, etc. can be wrong.

AUTHOR

Cai Qian
Karel Zak
Heiko Carstens

SEE ALSO

chcpu(8)

AVAILABILITY
The lscpu command is part of the util-linux package and is available
from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.

util-linux January 2013 LSCPU(1)