What hardware are you on?
I ask because a z196 has some high CPU costs for certain PSW Key-related
instructions.
For example, SPKA (Set PSW Key from Address) on a z196 shows up in CICS CPU
figures because it stalls the pipeline when changing PSW keys between key 8 and
key 9 -- or even when it doesn't change keys e.g. it is just 'going' from key 8
to key 8!
SPKA may be executed in CICS more than you think (consider User Exits -- GLUEs
and TRUEs -- some of which may have been inserted by your monitoring software).
Older (z10) and newer (zEC12) hardware does not have this SPKA problem.
But back to your question. You were allocating storage in key 9 to avoid any
extra SPKA instructions. So the above effect should not be directly relevant.
But it would still be interesting to know which hardware you are on. And even
more interesting if you can repeat your test on other hardware.
Your CICS region obviously has Storage Protection on. For the record, could
you tell us if it also has Transaction Isolation on?
Thanks for raising the issue Binyamin (an interesting find),
-- David Price
CPT Global
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