WAS v8.5 > Monitoring > Monitoring application flow > Why use request metrics?
Differences between Performance Monitoring Infrastructure and request metrics
PMI provides information about average system resource usage statistics, with no correlation between the data across different WebSphere Application Server components. For example, PMI provides information about average thread pool usage. Request metrics provides data about each individual transaction, correlating this information across the various WAS components to provide an end-to-end picture of the transaction, as shown in the following diagram:
Related concepts:
Data we can collect with request metrics
PMI