Infinite Loop Reported in the PATROL Agent Log or System Output Window

Why an infinite loop is reported in the PATROL Agent log or System Output Window.

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The PATROL Agent may report a possible infinite loop in its log file (*.errs) or in the System Output Window of the PATROL Console. In this case, the discovery is probably never completed and PATROL objects are probably missing in the PATROL Console.


While this message may be worrying, it is only due to an outdated loop mechanism of the PATROL Agent, as default settings often do not suit the computing power of recent servers.

By default, when a PSL script executes 500,000 instructions within 2 hours (7200 seconds), the PATROL Agent issues a warning, assuming that the PSL script has entered into an infinite loop. However, nowadays, it is very common for computers to execute as many instructions, and the more powerful the computer is, the more likely this is to occur.

The loop detection settings of the PATROL Agent can be changed and Sentry Software recommends that users set these PSL instruction thresholds. This can be achieved by modifying the following configuration variables with WPCONFIG/xpconfig or PCM:

  • /AgentSetup/AgentTuning/pslInstructionMax = 1000000
  • /AgentSetup/AgentTuning/pslInstructionPeriod = 1

This basically disables the loop detection mechanism of the PATROL Agent.
You may also need to disable or modify the alert thresholds of the PAWorkRateExecsMin parameter to prevent it from setting /AgentSetup/AgentTuning/runqSchedPolicy to 9, which significantly slows down the Agent Scheduling.


  • pslInstructionMax: sets the maximum number of instructions within pslInstructionPeriod seconds that a PSL process can execute without incurring an internal scheduling delay.
  • pslInstructionPeriod: sets period of time in seconds that a PSL process can execute the maximum number of instructions without incurring an internal scheduling delay.
  • PAWorkRateExecsMin: displays the number of operating system process executions performed by minute by the PATROL Agent.
  • Upgrading to PATROL Agent 3.8 and above will also solve this issue 

For more information concerning the PATROL Agent parameters, please contact the BMC Support team.

Disabling the loop detection mechanism of the PATROL Agent does have a drawback: you will not be able to detect infinite loops in other KMs anymore. Sentry Software recommends that you use this tip only when necessary and that you set the thresholds back to the default if your PATROL Agent does not behave properly.