CPUTIME is increasing since Compress/IMS has been upgraded to 20.0

Products

• Compress Data Compression (IMS Tools)

Issue/Introduction

The system has been upgraded as follows ;

Old :
z/OS 1.10
IMS 11
CPU zEC12

New :
z/OS 2.5
IMS 15.2
CPU z15

Running the EXPAND/SHRINK utility to process same data in the old and new environment, found that CPUTIME is increasing in the new environment.

	CPUTIME		SMF Value
Process	New	Old	New	Old
EXPAND	53.41sec	42.44sec	61.41sec	46.21sec
SHRINK	31.93sec	29.44sec	35.95sec	31.88sec

Environment

Compress/IMS 20.0

Resolution

EXPAND/SHRINK utility has no significantly different since 5.2.5, however, EXPAND/SHRINK utility code is so "old" and not suited for the new CPU pipelining execution. The code can cause flushing/refreshing CPU cache more often on the newer CPUs.