The PERF commands enable you to dynamically change the performance data gathering interval or update the RMF cycle time. The PERF command is only relevant when the PERF subtask is initialized (for reporting interval updates and RMF cycle updates) and/or the OSINFO subtask is initialized (for RMF cycle updates). Using the PERF command will only affect the currently running VP390 job; you must edit the initialization SYSIN cards MFCYCLE or PERF to retain the new values when the VP390 job is recycled. (See the Installation guide for syntax of the RMFCYCLE and PERF cards.) When updating INTERVAL, the new interval will take effect after the current interval time has elapsed.