idtune(1M) idtune(1M)
NAME
idtune - set or get the value of a tunable parameter
SYNOPSIS
/etc/conf/bin/idtune [-f | -m] [-c] parm value
/etc/conf/bin/idtune -g [-c] parm
/etc/conf/bin/idtune -d [-c] parm
DESCRIPTION
One of the ID/TP kernel configuration tools, idtune sets or
gets the value of an existing tunable parameter. idtune is
called by a Driver Software Package (DSP) installation or
removal script; it can also be invoked directly as a user-
level command. New tunable parameters must be installed using
idinstall(1M) and a DSP Mtune file before they can be accessed
using idtune.
Note that existing tunable parameter values must be modified
using the idtune command.
There are three different ways to use the idtune command,
which are explained in the USAGE section.
Options
-f Force the change of the tunable parameter parm to value
and suppress all confirmation messages. If the -c
option is used with the -f option, the values in both
stune.current and stune are changed; otherwise, only the
tunable parameter value in stune is changed. This
option does not apply to string tunables.
-m Change the value of parm, but only if the existing value
is smaller than the value specified by this idtune
command. If the -c option is used with the -m option,
the values in both stune.current and stune are changed;
otherwise, only the tunable parameter value in stune is
changed.
-c Apply the change to the tunable parameter in both stune
and stune.current. Note that all changes made to
stune.current will affect any loadable kernel modules
configured thereafter, and can potentially create
inconsistencies between the running kernel and the new
loadable kernel modules. For this reason, the -c option
should be used with caution.
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idtune(1M) idtune(1M)
-g Print the following sequence of values (separated by
white space) to stdout:
The current value of the tunable parameter
The default value, from the Mtune entry
The minimum valid value, from the Mtune entry
The maximum valid value, from the Mtune entry
Only the first two values apply to string tunables. For
tunables that are autotuned by default and have not had
this autotuning overridden with a specific value via
idtune, the values shown are for the present amount of
memory. If they have been overridden, the default,
minimum, and maximum are for the present amount of
memory, and the current is the specified value.
If the -c option is used with the -g option, the current
value in the kernel currently running is displayed;
otherwise, the value that will be used in the next
system build is displayed.
-d parm
Reset the tunable parameter to its default value. If
the tunable is autotuned by default, resets it to
autotuning. If the -c option is used with the -d
option, the values in both stune.current and stune are
reset; otherwise, only the tunable parameter value in
stune is reset. All confirmation messages are
suppressed.
Errors
The exit status will be non-zero if errors are encountered.
USAGE
The first form of the idtune command, with no options or with
-f or -m, is used to change the value of a parameter. The
tunable parameter to be changed is indicated by parm, and the
desired value for the tunable parameter is value.
By default, if the parameter in the stune file has a value,
you are asked to confirm the change with the following
message:
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idtune(1M) idtune(1M)
Tunable Parameter parm is currently set to old_value in
/etc/conf/cf.d/stune
Is it OK to change it to value? (y/n)
If the parameter is autotuned by default, you are asked to
confirm the change (which will override autotuning) with the
message:
Tunable Parameter parm is currently autotuned.
Is it OK to change it to value? (y/n)
For either of these questions, if you answer y, the change is
made. Otherwise, the tunable parameter will not be changed,
and the following message is displayed:
parm left at old_value
However, if you use the -f (force) option, the change is
always made and no messages are reported.
If you use the -m (minimum) option, and there is an existing
value which is greater than the desired value, no change is
made and no messages are reported. This option only applies
to integer tunables.
If you use the -c (current) option with the first form of the
idtune command, the change applies to both stune and
stune.current; otherwise, only the tunable parameter in stune
is affected. Since any change made to the stune.current file
will affect all the loadable kernel modules configured
thereafter, it is very easy to introduce inconsistencies
between the currently running kernel and the new loadable
kernel modules. Therefore, you should be extremely careful
when using the -c option.
If you are modifying system tunable parameters as part of a
device driver or application add-on package, you may want to
change parameter values without prompting the user for
confirmation. Your add-on package Install script could
override the existing value using the -f or -m options.
However, you must be careful not to
invalidate a tunable parameter modified earlier by the user or
another add-on package.
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idtune(1M) idtune(1M)
Any attempt to set a parameter to a value outside the valid
minimum/maximum (as given in the Mtune file) range will be
reported as an error, even when using the -f or -m options.
No validation is performed for string tunables.
The UNIX system kernel must be rebuilt [using idbuild(1M)] and
the system rebooted for any changes to tunable parameter
values in stune to take effect.
REFERENCES
idbuild(1M), idinstall(1M), Mtune(4), stune(4)
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