Tunable Kernel Parameters
NAME [Toc] [Back]
semaem - adjust-on-exit maximum value
VALUES [Toc] [Back]
Default [Toc] [Back]
Allowed values [Toc] [Back]
Maximum: semvmx or less than or equal to 32767.
DESCRIPTION [Toc] [Back]
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?
Restrictions on Changing [Toc] [Back]
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.
Hewlett-Packard Company - 1 - HP-UX 11i Version 2: Sep 2004
Tunable Kernel Parameters
WARNINGS [Toc] [Back]
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
AUTHOR [Toc] [Back]
semaem was developed by AT&T.
SEE ALSO [Toc] [Back]
semop(2), sema(5), semmni(5), semmns(5), semmnu(5), semmsl(5),
semume(5), semvmx(5), sysv_hash_locks(5).
Hewlett-Packard Company - 2 - HP-UX 11i Version 2: Sep 2004 [ Back ]