I will change the logic that establishes the SVC to add the module to LPA.
Your point of making it easier to identify things when looking at a dump is
a valid one. I was using the trace entry in the trace table as a trigger
mechanism for my code. By matching entries, I can give count and elapsed
time in my reporting logic. As to causing the trace table to wrap...dunno
what to say. There is so much activity getting traced already by default
that adding some extra entries for a user SVC just isn't going to be that
much. I've got it working, but really don't like the fact that it is
limited to PASN=HASN, and TCB mode code only. I'm going to try to
accomplish the same thing using PTRACE. If I get that working, I'll can the
SVC.
--Dave Day
----- Original Message -----
From: "Peter Relson" <[email protected]>
Newsgroups: bit.listserv.ibm-main
To: <[email protected]>
Sent: Sunday, January 01, 2012 10:23 AM
Subject: Re: Question on adding an SVC routine dynamically to a running
system
>I don't understand your comment. Unless by malicious use you mean that
the SVC would be executed over and over, just driving up overhead?
By "malicious" use I do mean that the SVC would be executed over and over,
but the overhead is irrelevant, as that is limited by the user's priority
and job class..
It could conceivably cause the trace table to fill more than it should and
potentially wrap with the lost of serviceability data that goes with such
occurrence. That is my concern.
I also have no idea what data you are tracing. Is it storage area(s)
identified by the caller?
Why is that short-sighted? Why would I ever set a slip on a BR R14? If
I need to know where the code is located in a dump, I can get the number
from my own data area, compute the offset into the SVC table, and then go
get it from that table.
Your SVC is not a BR R14. And even if it was, you are not the only one who
looks at dumps and no one else has any idea what your control structures
are. For example, a significant percentage of IBM's service time is spent
diagnosing situations that are not related to IBM code and any clue that
can help them is always appreciated. And the same is true of customers.
Suppose someone (not you) has a dump and the system trace shows the SVC
and for some reason they feel this should be investigated, but the SVC
routine storage is not in the dump because the dump has (E)SQA but not
(E)CSA. It can surely be helpful to be able to answer the question of
"what module is this?" which might let them answer the question of "who
owns this module?".
Peter Relson
z/OS Core Technology Design
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