HP-UX HB v13.00 Ch-07 - Kernel Configuration

HP-UX Handbook – Rev 13.00 Page 32 (of 33)
Chapter 07 Kernel Configuration
October 29, 2013
canauto n
default y
auto_default n
next_default y
signed n
flags 0x6c3
constraint nproc >= 100
constraint nproc <= 131072
174 Configuring the Kernel
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
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