NAME
core_addshmem_read — determines the inclusion of readable shared memory in a process core dump
VALUES
Allowed values
1 (on)
or
0 (off)
DESCRIPTION
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 read-only
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
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.
WARNINGS
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
core_addshmem_read
was developed by HP.
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