NSTREVENT(5)                                                   NSTREVENT(5)
                          Tunable Kernel Parameters



 NAME    [Toc]    [Back]
      NSTREVENT - maximum number of outstanding STREAMS bufcalls

 VALUES    [Toc]    [Back]
    Failsafe
      50

    Default    [Toc]    [Back]
      50

    Allowed values    [Toc]    [Back]
      0 - 2147483647

    Recommended values    [Toc]    [Back]
      50

 DESCRIPTION    [Toc]    [Back]
      This tunable limits the maximum number of outstanding bufcalls that
      are allowed to exist in the system at any given time.

      This tunable is intended to protect the system against resource
      overload caused by the combination of modules running in all streams
      issuing an excessive number of bufcalls.  The value selected should be
      equal to or greater than the combined maximum number of bufcalls that
      can be reasonably expected during normal operation from all streams on
      the system.  bufcalls are used by STREAMS modules in low memory
      situations.

    Who Is Expected to Change This Tunable?
      Any customer.

    Restrictions on Changing    [Toc]    [Back]
      Changes to this tunable take effect at next reboot.

    When Should the Value of This Tunable Be Raised?
      When the system has a lot of low memory situations.

    What Are the Side Effects of Raising the Value of This Tunable?
      If too big a number is chosen, the STREAMS subsystem preallocates more
      memory for internal data structures than may be needed.  This reduces
      the amount of  memory available to applications and the system.

    When Should the Value of This Tunable Be Lowered?
      If the tunable is increased for a particular STREAMS module/driver,
      this tunable can be lowered when that STREAMS module/driver is
      removed.  It should be returned to its previous value.  However, HP
      does not recommend a value lower than the default value.

    What Are the Side Effects of Lowering the Value of This Tunable?
      During low memory situations, it will bring down system performance.




 Hewlett-Packard Company            - 1 -      HP-UX 11i Version 2: Sep 2004






 NSTREVENT(5)                                                   NSTREVENT(5)
                          Tunable Kernel Parameters



    What Other Tunable Should Be Changed at the Same Time as This One?
      None.

 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]
      NSTREVENT was developed by HP.


 Hewlett-Packard Company            - 2 -      HP-UX 11i Version 2: Sep 2004