Home > CICS, CICS TS, CICSPlex SM, programming > CICSPlex SM API Performance Improvement

CICSPlex SM API Performance Improvement

Towards the end of last year we did some work on making some performance improvements to the CICSPlex SM API.

Most CICSPlex SM API commands (EXEC CPSM) will schedule an XDNR task to run in the CMAS that the MAS, or the batch job/TSO user is connected to. A number of these requests are very quick, so the overhead of CICS attaching and detaching the task compared to the processing actually performed by XDNR can be quite large.

APARs PK44521(CICSPlex SM 3.1) and PK51200(CICSPlex 3.2) have changed the XDNR processing so that these tasks can hang around for a short period of time and wait for more work. (Similar to the way CICS long running mirrors used to work.) If no work is received, the XDNR task will end, otherwise if the XDNRs keep getting work, they will stay running.

For heavy EXEC CPSM users, these changes can make worthwhile reductions in CMAS CPU usage and may improve the elapsed time of CICSPlex SM API programs.

Though of course as with all things performance related “results may vary”…..


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