process_id_min.5 (2010 09)

p
process_id_min(5) process_id_min(5)
(Tunable Kernel Parameters)
NAME
process_id_min - specify a minimum value for process IDs (PIDs)
VALUES
Failsafe
0
Default
0
Minimum
0
Maximum
process_id_max - 512
process_id_min
must be less than or equal to process_id_max - 512
. If the difference between
process_id_max
and process_id_min
inclusive is less than nproc, nproc is effectively limited to
this difference.
DESCRIPTION
The
process_id_min tunable specifies the minimum process ID (PID) value to generate for new
processes. It allows application developers to duplicate an environment where PID values are large for
the purpose of software validation.
This tunable is primarily intended for development environments.
Who is Expected to Change This Tunable?
Anyone interested in software program validation in an environment where PIDs have large values.
Restrictions on Changing
Changes to the tunable are effective immediately. However, any existing processes and their PIDs are
not changed.
It is recommended that the system be rebooted after specifying this tunable so that all PIDs in the system
will have values in the selected range.
When Should the Value of This Tunable Be Raised?
Raise this tunable to validate software for tolerance of large PID values in a development environment.
What Are the Side Effects of Raising the Value?
If the difference between
process_id_max
and process_id_min is less than nproc, the number of
processes allowed to exist simultaneously will be lower than the value of
nproc.
When Should the Value of This Tunable Be Lowered?
Lower this tunable when the system is meant to be moved from a development to a production environ-
ment.
What Are the Side Effects of Lowering the Value?
If the difference between
process_id_max and process_id_min
is less than nproc, the number of
processes allowed to exist simultaneously will be lower than the value of
nproc.
What Other Tunable Values Should Be Changed at the Same Time?
It may be desirable to change
nproc. The process_id_max tunable should, ideally, be set for the
maximum value when validating software which uses PIDs. When changing process_id_min it is
recommended that the system be rebooted to ensure all processes have PIDs within the desired range.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its
meaning changed in future releases of HP-UX.
The HP-UX kernel may silently round the selected values for process_id_max and/or
process_id_min (for example, to the nearest power of 2) in order to accommodate the PID generation
algorithm.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1