semmsl(5)semmsl(5)NAMEsemmsl - maximum number of System V IPC semaphores per identifier
VALUES
Failsafe
Default
Allowed values
DESCRIPTION
The tunable specifies the maximum number of individual System V IPC
semaphores per semaphore identifier (ID).
If an application attempts to exceed this limit, it will receive an
error from
For more information about System V semaphores, refer to the section of
the sema(5) manpage.
Who Is Expected to Change This Tunable?
Anyone.
When Should the Value of This Tunable Be Raised?
If applications require a larger number of semaphores per ID.
When Should the Value of This Tunable Be Lowered?
If application requirements for semaphores per ID has decreased or
there is a need to protect against ill-behaved applications.
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 sema‐
phore tunables include and Specifically, a change in the tunable may
require a change in the tunable.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parame‐
ter may be removed or have its meaning changed in future releases of
HP-UX.
Prior to HP-UX 11i Version 1 the maximum number of semaphores per ID
was an undocumented constant 2048 in the header file Typically applica‐
tions do not depend upon this limitation. For those that were compiled
with the old constant, tunable values higher than 2048 will generally
not be a problem. However, tunable values lower than 2048 may cause
other such applications to fail. These should be recoded to obtain the
current value from pstat_getipc(2).
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 val‐
ues. For information about the effects of installation on tunable val‐
ues, consult the documentation for the kernel software being installed.
For information about optional kernel software that was factory
installed on your system, see at
AUTHOR
was developed by AT&T.
SEE ALSOsemget(2), sema(5), semaem(5), semmns(5), semmni(5), semmnu(5),
semume(5), semvmx(5), sysv_hash_locks(5).
Tunable Kernel Parameters semmsl(5)