Re:Re: question about numbered user exits

Discussion created by ca.portal.admin on Oct 18, 2010
Hi Chris,

You are correct. IDMSCOMP and IDMSCOM are allowed to run in SRB mode.
All others require TCB mode. (It has nothing to do with the
name. In other words, you couldn't name a DB proc IDMSCOMP and
have it run in SRB mode). The majority of ""overhead"" when using
the zIIP option comes from swapping back and forth so the less
swapping the better.

In my opinion, with respect to the question related to
performance. I would suggest you hard link RHDCUXIT exits with
RHDCUXIT as opposed to defining them as programs and having
them called using Standard DC services. A simple BALR is a lot
faster than having the RHDCCXIT module issue a #CALL to a
program. The call and the code path is a lot longer than the
BALR. In a sense this is a lot like linking ""BIFS"" with ADS.
I've heard of and seen some fairly impressive numbers on this subject.
As far as SRB/TCB/SRB swapping, we will always swap to TCB mode
when calling an RHDCUXIT exit.

If you want to see where swaps are occurring you could specify
*****JuliusBaer Disclaimer***** This e-mail is for the intended recipient only and may contain confidential or privileged information. If you have received this e-mail by mistake, please contact us immediately and completely delete it (and any attachments) and do not forward it or inform any other person of its contents. If you send us messages by e-mail, we take this as your authorization to correspond with you by e-mail, however, we will not accept the electronic transmission of orders/instructions without a specific agreement being in place to govern the same. If you do not wish to receive any further e-mail correspondence please let us know. E-mail transmission cannot be guaranteed to be secure or error-free as information could be intercepted, amended, corrupted, lost, destroyed, arrive late or incomplete, or conta""CSATST49"" in your SYSIDMS file. I would only do this on a non
production system simply because in addition to counting the
swaps there are some WTORs produced which might not amuse the
operators. Don't get me wrong, we can use this in production
systems if the situation warrants but as a simple matter of
gathering information over a period of time it might be a bit
much. It is fine for TEST, QA, Pre-Production, development
systems or whatever your site refers to them as.

""DCMT D SUBT"" will report on the swaps. Here's a sample:


*** Display all subtasks ***

Work Task dispatch

Name Nr type Status count Wakeup count Total
CPU time
---- -- ---- ------ ------------- ------------
MAINTASK 01 IDMS BUSY 1,327 1,228

CHGEMODE table display

Address Program Offset Call cnt TCB->SRB SRB->TCB

-------- -------- -------- ---------- ---------- ----------

3D4B28EA RHDCWAIT 000032EA 1 1 0

3D554058 RHDCTSKI 00000458 22 0 22

3D54C514 RHDCMSTR 00000114 1 1 0

3D52B8F2 RHDCWTL 00001AF2 84 0 84