LOOP EX Intro

in deutsch bitte

Prolog

During a conversation the subject of loop detection came up. This is indeed possible with the code that does the surveilance. The handling has to be a little different. Also the action when limit are exceeded does differ (I guess).
Here is some REXX-code I wrote around PICC01 (the HLASM-module that extracts the CPU-load).

Flow of the Program

The whole story is a constant monitoring of the CPU. Whenever the threshhold is exceeded the REXX goes into "intensive" mode. It does in fact deactivate and reactivate all of the partitions it has been told about to see if the delta between the active and non-active is greater than a predefined value.
Since the QUERY TD can not picking up changes in CPU-load, if there is no GETJA (step end) occuring, the module PICC02 was written. All it does is issue a single GETJA to achieve update of the external tables.
Once deactivation has reached that delta, the REXX issues the defined command and goes back into normal mode.

Consequences

In situations where a CPU-busy light is not constantly monitored and there is a chance of a (low level) program to grab all of the remaining CPU AND someone has to pay for this,....
.... PICAPCPU can help as well.

for e-mail to the author.
The source of the REXX, that does the loop-check.