Autotune(4dsp)


Autotune -- autotuning tunable parameter definitions

Synopsis

   Autotune 

Description

One of the Installable Driver/Tunable Parameters kernel configuration files, an Autotune file, contains definitions for the default, minimum, and maximum values for tunables that should change with the amount of memory present. Lines in the /etc/conf/cf.d/mtune file are created for these variables based on this information. The information is also passed to the kernel as a structure in the /etc/conf/pack.d/module-name/tune.c file. This is used to retune the tunable at boot, if the memory size has changed. The autotuning can be overridden by using idtune(1M). Autotune files exist on a per-module basis, for those modules that have autotuned parameters. idinstall(1M) stores the module's Autotune file information in /etc/conf/autotune.d/module-name, where the file module-name is the name of the module being installed. Package scripts should never access /etc/conf/autotune.d files directly; only the idinstall and idtune commands should be used.

Each tunable is specified on multiple lines of the form:

   parameter-name min-max-or-default linear-or-step memsize value 

All fields are positional and must be separated by white space. Blank lines and lines beginning with ``#'' or ``*'' are considered comments and ignored.

The Autotune file fields are:

parameter-name
A string (maximum of 20 characters) used as the parameter-name in the mtune file line constructed.

min-max-or-default
A string used to specify whether this line pertains to the default value (DEF), minimum value (MIN), or maximum value (MAX) in the mtune file line constructed.

linear-or-step
The string LINEAR or STEP, used to determine how to calculate the value for memory sizes in between those specified. Linear will use linear interpolation between the two closest points, or linear extrapolation from the last two points if the largest memory size specified is smaller than the amount of memory in the system and has LINEAR specified. STEP will use the value from the next smaller memory size.

memsize
The memory size, in megabytes, for which this line specifies the tunable's minimum, maximum, or default value.

value
The value to be assigned to the tunable's minimum, maximum, or default value at the given memory size.

For detailed information on Autotune parameters, refer to the tunable parameters chapter in your system administration documentation.

References

idbuild(1M), idinstall(1M), idtune(1M), Mtune(4dsp), Space.c(4dsp), stune(4dsp)
30 January 1998
© 1998 The Santa Cruz Operation, Inc. All rights reserved.