Michael,
Have you tried taking an in-flight dump (z/OS command : DUMP COMM=('foo') ) of
the address space and then running IPCS against it to see where the storage is
being used (VERBX VSMDATA and RSMDATA would be good place to start).
Rob Scott
Developer
Rocket Software
275 Grove Street * Newton, MA 02466-2272 * USA
Tel: +1.617.614.2305
Email: [email protected]
Web: www.rocketsoftware.com
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of
Michael Knigge
Sent: 09 October 2009 09:34
To: [email protected]
Subject: Does a DD-Statement "waste memory" after dealloc?
All,
I currently try to find a obscure memory leak in one of our applications. After
some days our appl occupies ~17.000 pages of real memory (needs just ~1.500
after startup).
As we track all malloc(), calloc(), realloc() and free() function calls, I can
say that there is no obvious memory leak....
Now... after I've looked at the JESYSMSG I've noticed that we've done approx
17.000 DYNALLOCs, everyone with a different DD-Name (we let the z/OS generate a
unique one, like "SYS00001", "SYS00002", "SYS00003" and so on)..... to be
clear: *NOT* ~17.000 at the same time. mostly only one at the same time...
Of couse, we deallocate them after we've finished using the DD-Name, but I
wonder that even after a DEALLOC (with SVC99) there is some space still
occupied....
Why? Because of performance? Because of some kind of control block that can
only grow but not shrink?
Thanks,
Michael
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