1

Performance Essential (PSP, Rocket Software offering) reduces the CPU time, I/O for a COBOL program program. How can we do it manually without using their product to calculate optimal balance between memory and speed for Cobol program?

One of the Cobol program is running longer (35 min). When, I increased the CI size from 4096 to 8192 for one of the VSAM file, then noticed significant improvement in CPU time from 35 minutes to 36 seconds.

Also, after enabling PSP, the CPU time gets reduced to 41 seconds. I found on their documentation that PSP reduced the I/O and enhances buffering to achieve that. Does that means, is PSP modifying the CI size for all VSAM files and block size for Non VSAM? Also, how the buffer space requirement is being calculated for a Cobol program? What are the different ways to calculate the buffer space (total space taken by a program) taken by a Cobol program?

Earlier:

CISZ ( 4096)

After:

CISZ ( 8192 )
Hogstrom
  • 3,581
  • 2
  • 9
  • 25
deepaklearner
  • 151
  • 1
  • 6
  • 22

1 Answers1

1

According to their website the product Rocket Performance Essentials

Rocket Performance Essential Systems automatically adjusts the buffers to allow more I/O to flow at a given time without rewriting applications or JCL. This reduces the number of I/O dramatically while increasing and freeing system resource to provide maximum utilization

The net is that larger buffer sizes require less system overhead as you are reading and writing larger blocks of data with reduced I/O overhead. Also, you are waiting less for I/O wait time so your elapsed time is reduced as well.

For details on all the methods Performance Essentials administers I’d look further into their technical documentation on their website.

You can achieve the same performance but you will need to continuously keep up. The advantage of a tool like this is it optimizes automagically for you.

Hogstrom
  • 3,581
  • 2
  • 9
  • 25