semaem(5)                                                         semaem(5)
                          Tunable Kernel Parameters



 NAME    [Toc]    [Back]
      semaem - adjust-on-exit maximum value

 VALUES    [Toc]    [Back]
    Failsafe
      16384

    Default    [Toc]    [Back]
      16384

    Allowed values    [Toc]    [Back]
      Minimum: 0

      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?
      Anyone.

    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






 semaem(5)                                                         semaem(5)
                          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
      http://docs.hp.com.

 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