kmtune(1M) kmtune(1M)
NAME [Toc] [Back]
kmtune - query, set, or reset system parameters
SYNOPSIS [Toc] [Back]
/usr/sbin/kmtune [-d] [-l] [[-q name]...] [-S system_file]
/usr/sbin/kmtune [-u] [[-s name{=|+}value]...] [[-r name]...]
[-c comment] [-S system_file]
/usr/sbin/kmtune [[-e value]...]
DESCRIPTION [Toc] [Back]
kmtune is an obsolete command that is replaced by kctune(1M). Users
are encouraged to migrate to kctune(1M). kmtune will be removed in a
future release of HP-UX. The behavior of some of kmtune's options have
changed and they are noted in the appropriate sections below.
kmtune is used to query, set, or reset system parameters. kmtune
displays the planned values of all system parameters when used without
any options or with the -l option. kmtune gathers information on the
running kernel using the tuneinfo2() system call.
By default, kmtune's changes affect the currently running kernel
configuration, marked to take effect at next boot. If the -u option
is specified, kmtune's changes affect the current configuration, and
take effect immediately. See kconfig(5) for more information on
kernel configurations.
Options [Toc] [Back]
The following options are recognized by kmtune:
-c text Specify an optional comment string. All changes to the
kernel parameters are logged with the date, old value,
new value, user id and this comment. This option is
used with -r and -s. The comment text will generally
need to be quoted so that it is interpreted as a single
parameter by the shell. The comment text may contain
newlines. The log is written to the file
/var/adm/kc.log. See kconfig(5) and kclog(1M) for more
information about the kernel configuration log file.
-d Print a brief difference report. Only parameters where
the planned and current values are different are
listed. If the planned value is a formula, it is NOT
considered different from the current value. This
option is useful to insure that only desired changes
will be made on a subsequent invocation of kmtune -u.
The -d option cannot be used with the -r, -s, or -u
options.
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-e value Evaluate the expression given by "value". The
expression is anything allowed in the -s option. The
output will always be in decimal.
-l Print a detailed report. The -l option cannot be used
with the -r, -s or -u options.
-q name Query the value of the specified system parameter.
-r name Reset the value of the specified system parameter to
the default.
-s name{=|+}value
Set the value of the specified system parameter. If the
separator is an equal sign (=), the parameter is set to
the value specified. If the separator is a plus sign
(+), the parameter is incremented by the value
specified. Negative values cannot be used with plus
sign (+). The name{=|+}value format must not include
spaces or tabs.
-S system_file This option is obsolete. It is accepted for
compatibility purposes but has no effect.
-u Update the current kernel configuration. This modifies
the -s and -r options so that their effects take effect
immediately rather than at next boot. The whole
command will fail if any non dynamic parameters are
being set. The -s and -r options are processed in the
order they are listed. At least one -s or -r option
must be specified.
The expressions used with the -s and -e options are built of literal
values, the upper case names of other kernel parameters, and the
following operators: ( and ), the unary operators ~, !, -, and +, the
binary operators *, /, %, +, -, <<, >>, <, <=, >, >=, &, ~, |, ==, !=,
&&, and ||, and the ternary operator ?:.
Using -s to create a circular dependency in the values of the kernel
parameters is not allowed.
Notes [Toc] [Back]
Changing kernel parameters dynamically is a fairly new feature.
Programs using pstat(2), getrlimit(2), or sysconf(2) may have been
written with the previously correct assumption that the returned
values do not vary while the system is running. The use of kmtune to
modify the running kernel may cause such programs to produce erroneous
results or even abort.
Some dynamic kernel parameters can be raised dynamically, but cannot
be lowered without rebuilding the kernel and rebooting. See the
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manual pages for those parameters for details.
When dynamically lowering per-process limits, processes that exceed
the new limit will be "grandfathered". Such processes will retain the
old limit. The old limit will also apply to any child processes they
create after the change. Some parameters have exceptions to this
general policy; see the manual pages for those parameters for details.
It is possible to put multiple -s and -r options on a single kmtune
command. kmtune will try to make all of the changes, in the order
listed. If an error occurs with one of the changes, the state of the
other changes is not defined.
RETURN VALUE [Toc] [Back]
Upon completion, kmtune returns with one of the following exit values:
0 Successful.
1 Changes have been made and will take effect at next boot.
2 An error occurred.
Results of query requests are sent to stdout. Error and warning
messages are sent to stderr.
FILES [Toc] [Back]
/var/adm/kc.log Log of all kernel configuration changes
SEE ALSO [Toc] [Back]
kclog(1M), kconfig(5), kctune(1M), settune(2), tuneinfo2(2), and the
individual tunable parameter manual pages in section 5.
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