Thanks. I've been told that CICS on z/OS (we just migrated from VSE) inherantly utilizes multiple CPs (we have a 3-way), but other than the little DB2 access we have this appears to not be true without utilization of threadsafe and/or OPENAPI. I just wanted to confirm my assumptions.
>From what I know about our applications we could probably define them >THREADSAFE/OPENAPI safely. We use CWA, but as read-only other than one >program that runs only at start-up and at midnight each day to update some CWA >data fields. We make almost no use of GETMAIN SHARED, and again only a single >program run at startup loads the area. All other programs only read it. I need to further investigate our use of non-threadsafe CICS commands. Annoyingly, we're just now looking in to using Shared Data Tables and I now see that they are not threadsafe! Annoying! Oh well. Thanks! Frank -- Frank Swarbrick Applications Architect - Mainframe Applications Development FirstBank Data Corporation - Lakewood, CO USA P: 303-235-1403 On 7/24/2010 at 10:05 AM, in message <[email protected]>, "Joel C. Ewing" <[email protected]> wrote: > On 07/22/2010 05:42 AM, Jan MOEYERSONS wrote: >> On Tue, 20 Jul 2010 09:15:00 -0600, Frank Swarbrick >> <[email protected]> wrote: >> >>> Naive question, perhaps... Is OPENAPI and THREADSAFE required for a CICS >> region to use more than one CPU? >> >> I think CICS is using all CPUs it can get his hands on. The CICS region is >> competing for resources, just like any other work in MVS. >> >> Whether a single application program within your CICS will use more than one > >> CPU at any given moment in time, is entirely up to the design and >> implementation of your application code... >> >> Why not ask the question over on CICS-L? You will get better quality answers >> than mine. >> Cheers, >> Jantje. > ... > Frank, > Prior to relatively recent CICS support for multi-threaded transaction > code and prior to DB2 applications all transactions under one CICS > region were single threaded under one TCB effectively limiting the > region to a maximum of one CPU, and the only way to get more CP resource > on a multi-CP system was to run multiple CICS regions. With > transactions using DB2, the DB2 queries could be processed under other > TCBs while additional transaction code was running under the application > transaction TCB, but in our experience even in a heavy DB2 environment > this still only allowed CICS to effectively average somewhere between 1 > and 2 CPs concurrently. > > CICS now supports multiple TCBs for running transaction code, but you > are correct that this adds additional requirements on transaction code > in order to be able to run in that mode, and I'm pretty sure one of > those is "threadsafe". I would think this should now allow CICS to > utilize multiple CPs more effectively, but we aren't in a position to > see just how well because we still have our production CICS load divided > over at least 12 CICS regions for isolation and tuning reasons. >>> The information contained in this electronic communication and any document attached hereto or transmitted herewith is confidential and intended for the exclusive use of the individual or entity named above. If the reader of this message is not the intended recipient or the employee or agent responsible for delivering it to the intended recipient, you are hereby notified that any examination, use, dissemination, distribution or copying of this communication or any part thereof is strictly prohibited. If you have received this communication in error, please immediately notify the sender by reply e-mail and destroy this communication. Thank you. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
