RMF

RMF, the Resource Measurement Facility, measures performance on z/OS. It collects data about processors, memory, disks, address spaces and workloads, and presents it as reports and screens.

It works at two time scales. For the long term, it writes SMF records at regular intervals, and a reporting program called the postprocessor turns them into reports used for capacity planning and to check whether WLM goals were met. For the short term, Monitor III shows what is happening now, or in the last few minutes, on interactive screens.

Monitor III is especially useful for problems. It shows, for each piece of work, what it has been waiting for: the processor, a disk, an ENQ, or storage. That turns "the job is slow" into a precise reason.

Performance analysts and system programmers use RMF most. As a developer, you may be shown RMF data when your job uses more processor time than expected, or when an online service is missing its response time goal.