NAME
semaem — adjust-on-exit maximum value
VALUES
Allowed values
Minimum: 0
Maximum: semvmx
or less than or equal to
32767.
DESCRIPTION
The
semaem
tunable specifies maximum cumulative "undo" value for any one
semaphore as changed any one single process.
That is, a process is allowed up to
semaem
outstanding increments or decrements on a semaphore
for which
SEM_UNDO
has been specified.
If an application attempts to exceed the limit, it will receive an
ERANGE
error from
semop().
For more information about System V semaphores, refer to the
Overview
section of the
sema(5)
manpage.
Who Is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to this tunable take effect at the next reboot.
When Should the Value of This Tunable Be Raised?
When an application is expected to
have large increments or decrements of a semaphore, or
a large series of increments without intervening decrements,
or a large series of decrements without intervening increments,
for which "undo" semantics are desired.
When Should the Value of This Tunable Be Lowered?
When applications no longer have the need for a raised value.
What Other Tunable Values Should Be Changed at the Same Time?
All the System V semaphore tunables are interrelated and should
not
be treated as independent variables.
The tunables must be evaluated as a system to ensure they reflect the
application requirements.
The semaphore tunables include
semaem,
semmni,
semmns,
semmnu,
semmsl,
semume,
semvmx,
and
sysv_hash_locks.
Specifically, the
semvmx
and the
semaem
values may need adjustment together.
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.
Installation of optional kernel software, from HP or other vendors,
may cause changes to tunable parameter values. After installation,
some tunable parameters may no longer be at the default or
recommended values. For information about the effects of
installation on tunable values, consult the documentation
for the kernel software being installed.
For information about optional kernel software that was
factory installed on your system, see
HP-UX Release Notes
at
http://docs.hp.com.
AUTHOR
semaem
was developed by AT&T.
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