core_addshmem_read(5)                                 core_addshmem_read(5)
                          Tunable Kernel Parameters



 NAME    [Toc]    [Back]
      core_addshmem_read - determines the inclusion of readable shared
      memory in a process core dump

 VALUES    [Toc]    [Back]
    Failsafe
      0 (off)

    Default    [Toc]    [Back]
      0 (off)

    Allowed values    [Toc]    [Back]
      1 (on) or 0 (off)

 DESCRIPTION    [Toc]    [Back]
      The core_addshmem_read tunable was added in response to a problem
      where a customer was limited in debugging a user-level process crash
      because shared memory segments were not written as part of the core
      file.

      Upon core dump, the sections of user memory labeled as shared readonly
 are written (along with the normal data sections) if this tunable
      is set to 1 (on), and left out if it is set to 0 (off).

    Who is Expected to Change This Tunable?
      Anyone.

    Restrictions on Changing    [Toc]    [Back]
      Changes to this tunable take effect immediately.

    When Should the Value of This Tunable Be Raised?
      When you wish to include read-only shared memory segments in user core
      files due to debugging needs by developers or maintainers on the
      system.

    What Are the Side Effects of Raising the Value?
      User process core files would increase in most cases (most
      applications use at least some shared memory).  This could be a
      problem on systems where disk space is at a premium.

    When Should the Value of This Tunable Be Lowered?
      When there is no need for debugging core files where shared memory
      corruption or data values are in question.

    What Are the Side Effects of Lowering the Value?
      Core files will tend to be smaller.

    What Other Tunable Values Should Be Changed at the Same Time?
      Certainly think about core_addshmem_write, which does the same thing
      for read/write shared memory segments.




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






 core_addshmem_read(5)                                 core_addshmem_read(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]
      core_addshmem_read was developed by HP.


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