In the old days, a CICS subsystem's capacity was limited by
the amount of CPU TCB time needed for that single QR TCB.

Based on my analysis when OTE was brand new, of the CPU time
consumed by each of these new CICS TCBs, I planned this post
to argue that going to OTE didn't help much, because most of
the CICS CPU time was still being spent under the QR TCB.

I could NOT have been more wrong!

Analyzing new CICS/TS 4.1 Open Beta data from a VERY 
aggressive OTE exploiter site shows (from their
SMF 110, subtype 2 Dispatcher Statistics segments, 
MXG CICDS and CICINTRV datasets):

Total TCB CPU in Dispatcher Records  = 13,080 seconds
Total TCB CPU in QR TCB              =  2,776 seconds
Total TCB CPU in L8 TCB              = 10,298 seconds
Total TCB CPU in all other TCBs      =      6 seconds

Aha, you say, OTE still doesn't help; the CPU time just moved 
from the QR TCB to the L8 TCB, so the capacity limit just moved
from one TCB to the other, right?

Wrong again.
  
While the QR TCB can attach only a single TCB, these new TCBs
can attach multiple TCBs; in fact, the SMF data shows that 
the L8 TCB attached a maximum of 22 TCBs, each of which 
is a separate dispatchable unit.

So, it REALLY does look like that these multiple OTE TCBs 
do eliminate the old "one-TCB" CICS capacity limitations,
and does indeed spread your CICS time across MANY TCBs.

(Total SRB time in the Dispatcher Records was only 65 seconds.)

Barry Merrill

Herbert W. Barry Merrill, PhD
President-Programmer
Merrill Consultants
MXG Software
10717 Cromwell Drive
Dallas, TX 75229

 ba...@mxg.com
 http://www.mxg.com 
               admin questions:       ad...@mxg.com
               technical questions:  supp...@mxg.com
 tel: 214 351 1966
 fax: 214 350 3694


 

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