Tuning Your Applications › Other Delays

Other Delays

This section describes the various other types of delays, and the possible reasons for them.

Demand paging

One or more of the following situations might be present in the program or in one of the subroutines it calls:

• a program is link-edited inefficiently
• data arrays are used incorrectly
• too many data buffers are specified

VIO paging

Indicates one of the following reasons:

VIO data sets are simulated files that can significantly reduce I/O delays.

They are essentially paging files that are managed by z/OS. The only drawback is that, if the application requests a record that is not in the VIO panel, a page fault will occur that will not be processed concurrently with the application program and the application will experience delay.

Swapping

This delay is caused when

• the program or one of its subroutines is requesting system resources that are unavailable.
• the site’s tuning parameters are improperly set.