System Tunable Mapping: Tru64 UNIX to HP-UX 11i v2
msg_mni (Tru64 UNIX) versus msgmni (HP-UX)
This parameter specifies the maximum number of message queues that can exist simultaneously on the
system.
T
he default value of this parameter is different for Tru64 UNIX and HP-UX. The default setting is 50 for
Tru64 UNIX, and 512 for HP-UX. The maximum value allowed on this parameter is higher for Tru64
UNIX than HP-UX. The maximum value for Tru64 UNIX is INT_MAX; the maximum value for HP-UX is
32767.
System V IPC Semaphores Attributes
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 relfect the application
requirements.
The following table shows the system tuning options for System V IPC semaphores attributes:
Tru64 UNIX HP-UX Dynamic on HP-UX Description
sem_aem
semaem
No Maximum amount a semaphore value can be
changed by a semaphore “undo” operation.
sem_mni
semmni
No Maximum number of semaphores identifiers
that can be used on the system at one time.
sem_msl
semmsl
Yes On Tru64, maximum number of semaphores
per process at one time.
On HP-UX, maximum number of semaphores
per semaphore identifier.
sem_ume
semume
No Maximum number of System V IPC undo
entries per process.
sem_vmx
semvmx
No Maximum value of any single System V IPC
semaphore.
sem_opm
N/A N/A Maximum number of operations that can be
outstanding on a single System V semaphore
at one time.
On HP-UX, semopm is not a tunable, but it is
limited to 500.
sem_aem (Tru64 UNIX) versus semaem (HP-UX)
This parameter specifies the maximum cumulative "undo" value for any one semaphore as changed
by any one single process.
The default value of this parameter is the same for Tru64 UNIX and HP-UX. However, the maximum
value allowed on this parameter is higher for Tru64 UNIX than HP-UX. The maximum value for Tru64
UNIX is 65536; the maximum value for HP-UX is
semvmx or 32767, whichever is smaller, on HP-UX.
sem_mni (Tru64 UNIX) versus semmni (HP-UX)
This parameter specifies the maximum number of IPC semaphore identifiers that can exist
simultaneously on the system.
The default value of this parameter is different for Tru64 UNIX and HP-UX. The default setting is 10
(the system rounds the number to the value associated with the next higher power of two, which is 16)
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