HP-UX System Administrator's Guide: Configuration Management

constraint nproc >= semmnu + 4
constraint nproc >= maxuprc + 5
constraint nproc <= nkthread - 100
Use a comma-separated list with the -P option to display the categories you want.
# kctune -P name,current maxuprc nproc
name maxuprc
current 256
name nproc
current 4200
Interpreting Tunable Information
Looking at the sample output above, you can see that each tunable has a name and a
textual description. Each tunable is associated with a kernel module whose name is
listed in the verbose output (or in the table output if -g is specified). Tunables can be
seen and changed only if they are associated with a module that is installed on the
system (or are user-defined). The module does not have to be in use.
When displaying tunable information for the currently running system, kctune includes
the current tunable value and the expression used to compute it. If changes to the
tunable’s value are being held for next boot, the next boot value and expression are
also shown. Verbose listings also show the value the tunable had when the system was
last booted. When displaying tunable information for a saved configuration, kctune
displays only a current value.
Tunable values are computed integer expressions, which can refer to other tunable
values. (Circular references are not permitted.) The value of a tunable could be 4200,
or 0x400, or 12*1024, or 4*nproc+20. Values and expressions use the syntax of the
C programming language. Therefore, numbers can be written in decimal (256), octal
(01000), or hexadecimal (0x100). Expressions can use the following operators and
symbols:
( ) ~ ! - + * / % << >> < <= > >= & ^ | == != && || ?:
A few tunables also support values specified as percentages, for example, 10%.
White space is not permitted in any tunable expression. For backward compatibility,
tunable names used in expressions can appear in all capitals, but this usage is
discouraged and support for it will be removed in a future release.
All kernel tunables have a default value, which is chosen by the developer, and is
shown in the verbose output. For some tunables, the default value is fixed and never
changes. For other tunables, a new default value is chosen by the system at boot time.
Still others can be automatically tuned, which means that the default value can change
periodically while the system is running, in response to changing system resources
and needs. When a tunable is set to default, its expression is reported as Default, as
seen in the examples above. In these cases, the system is free to choose the value it
Managing Kernel Tunable Parameters with kctune 173