The Roots and Evolution of the RMF and SMF for Mainframe Performance Data (Part 2)

George DodsonBy George Dodson

This is part 2 of this blog. If you haven’t read the first section, you can read that here.

After being announced as a product in 1974, RMF was further expanded to provide more capabilities such as RMF Monitor 2 and RMF Monitor 3. These provided real time insight into the internal workings of z/OS to help understand and manage the performance of the z/OS infrastructure. The value of the RMF performance measurement data has been proven over the decades as it, or a compatible product from BMC named CMF, is used in every mainframe shop today. Many new record types have been added in recent years as the z/OS infrastructure capabilities continue to evolve.

A related product – Systems Management Facility or SMF – was originally created to provide resource usage information for chargeback purposes. SMF captured application usage statistics, but was not always able to capture the entire associated system overhead. Eventually, SMF and RMF were expanded to capture detailed statistics about all parts of the mainframe workloads and infrastructure operation, including details about third party vendor devices such as storage arrays. RMF and SMF now generate what is likely the most robust and detailed performance and configuration data of any commercial computing environment in the data center.

As the data sources to report on the performance of the workloads and the computer infrastructure grew, different performance tools were created to display and analyze the data. The information in the data was very complex and the total amount of data captured is overwhelming, creating challenges to identify performance problems. Typically, this requires analysts who have extensive insight into the specific infrastructure areas being analyzed, and an understanding of how they respond to different applications workloads. As applications have grown more complex, more real-time, with more platforms and components involved, the performance analysis task also has become more difficult.

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The Roots and Evolution of the RMF and SMF for Mainframe Performance Data (Part 1)

George Dodson

By George Dodson

This blog originally appeared as an article in Enterprise Executive.

Computer professionals have been interested in determining how to make computer applications run faster and determine the causes of slow running applications for more than 50 years. In the early days, computer performance was in some ways easy because electronic components were soldered in place. To understand what was happening at any point in the circuitry, we simply attached a probe and examined the electronic wave information on an oscilloscope.

Eventually, we were able to measure activity at key points in the computer circuitry to determine things like CPU Utilization, Channel Utilization and Input/Output response times. However, this method still had many shortcomings. First, the number of probes was very small, usually less than 40. Secondly, this method gives no insight into operating system functions or application operations that may be causing tremendous overhead. And of course, when integrated circuits were developed, the probe points went away.

In 1966 I joined an IBM team that was focusing on a better way to conduct benchmarks in what was then named an IBM Systems Center. Customers considering computer upgrades would come to our data center to determine how their programs would operate on newly released hardware. But it was simply not possible to host every customer in this way.

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