Re: Is the Program Status Data Structure Externally Defined?

On 2010/12/6 9:06 PM, Rory Hewitt wrote:

...
I typically code new RPG programs from a template which includes the above
copybook, and I've never noticed any performance hit. I assume the hit would
simply be at startup, where it has to call e.g. MATPGMNM or its equivalent
to get the program library etc. ...

Rory, you're right that the PSDS hit is only at startup. When that section of the manual was written back in V3R1, there was a noticeable difference in performance for repeated calls to a program with a maximum sized PSDS vs one with an 80-byte PSDS, where both programs set on LR so the initialization cost was incurred on every call.

The various APIs that the RPG runtime uses to get the information may have got faster over time, possibly even during the CISC -> RISC change in V3R2.

Our tests in V3R1 used programs that did nothing except set on LR. Even then, if the programs actually did a reasonable amount of work, the difference due to PSDS initialization was not noticeable. (So arguably, we could have just left that information out of the manual ...)