Program Fetch Performance
Posted: Sat Jun 29, 2013 10:46 pm
I got the idea to experiment with program fetch performance. To do this I defined 3 environments.
To me, the real surprise was the PDSE performance relative to PDS performance. Long time readers of this forum probably know I am not an enthusiastic supporter of PDSE. In my experience PDSE requires more CPU and elapsed time than PDS; this was the first time I actually tried to measure PDSE fetch performance. At another level, this is not a big surprise. The structure of load modules dictates poor I/O performance, particularly for large load modules. The order of magnitude performance improvement, though was a surprise to me.
- Link List
- A PDS that is a copy of SYS1.LINKLIB
- A PDSE that is a copy of SYS1.LINKLIB
- LINKLST - 0.34
- PDS - 0.29
- PDSE - 0.03
To me, the real surprise was the PDSE performance relative to PDS performance. Long time readers of this forum probably know I am not an enthusiastic supporter of PDSE. In my experience PDSE requires more CPU and elapsed time than PDS; this was the first time I actually tried to measure PDSE fetch performance. At another level, this is not a big surprise. The structure of load modules dictates poor I/O performance, particularly for large load modules. The order of magnitude performance improvement, though was a surprise to me.