The kstat utility examines the available kernel statistics, or kstats, on the system and reports those statistics which match the criteria specified on the command line. Each matching statistic is printed with its module, instance, and name fields, as well as its actual value.

Kernel statistics may be published by various kernel subsystems, such as drivers or loadable modules; each kstat has a module field that denotes its publisher. Since each module may have countable entities (such as multiple disks associated with the sd(7D) driver) for which it wishes to report statistics, the kstat also has an instance field to index the statistics for each entity; kstat instances are numbered starting from zero. Finally, the kstat is given a name unique within its module.

Each kstat may be a special kstat type, an array of name-value pairs, or raw data. In the name-value case, each reported value is given a label, which we refer to as the statistic. Known raw and special kstats are given statistic labels for each of their values by kstat; thus, all published values can be referenced as module:instance:name:statistic.

When invoked without any module operands or options, kstat will match all defined statistics on the system. Example invocations are provided below. All times are displayed as fractional seconds since system boot.

The tests specified by the following options are logically ANDed, and all matching kstats will be selected. A regular expression containing shell meta-characters must be protected from the shell by enclosing it with the appropriate quotes.

The argument for the -c, -i, -m, -n, and -s options may be specified as a shell glob pattern, or a Perl regular expression enclosed in '/' characters.

-c class

Displays only kstats that match the specified class.

-i instance

Displays only kstats that match the specified instance.

-l

Lists matching kstat names without displaying values.

-m module

Displays only kstats that match the specified module.

-n name

Displays only kstats that match the specified name.

-p

Displays output in parseable format. All example output in this document is given in this format. If this option is not specified, kstat produces output in a human-readable, table format.

-q

Displays no output, but return appropriate exit status for matches against given criteria.

-s statistic

Displays only kstats that match the specified statistic.

-T d | u

Displays a time stamp before each statistics block, either in ctime(3C) format ('d') or as an alphanumeric representation of the value returned by time(2) ('u').

The following operands are supported:

module:instance:name:statistic

Alternate method of specifying module, instance, name, and statistic as described above. Each of the module, instance, name, or statistic specifiers may be a shell glob pattern or a Perl regular expression enclosed by '/' characters. It is possible to use both specifier types within a single operand. Leaving a specifier empty is equivalent to using the '*' glob pattern for that specifier.

interval

The number of seconds between reports.

count

The number of reports to be printed.

In the following examples, all the command lines in a block produce the same output, as shown immediately below. The exact statistics and values will of course vary from machine to machine.

The following exit values are returned:

0

One or more statistics were matched.

1

No statistics were matched.

2

Invalid command line options were specified.

3

A fatal error occurred.

/dev/kstat

kernel statistics driver

See attributes(5) for descriptions of the following attributes:

sh(1), time(2), ctime(3C)gmatch(3GEN), kstat(3KSTAT), attributes(5), kstat(7D), sd(7D), kstat(9S)

If the pattern argument contains glob or Perl RE meta-characters which are also shell meta-characters, it will be necessary to enclose the pattern with appropriate shell quotes.