overview of the perfmon project

The goal of this project is to design a standard kernel interface, called perfmon2, to access the hardware performance counters available on all modern processors.

We are initially using Linux on the Itanium Processor Family (IPF) as the testbed because the Itanium Performance Monitoring Unit (PMU) is very interesting and also because monitoring is very important for this processor architecture. However there is nothing specific to IPF in the design and the interface could be implemented on other architectures as well.

As part of the project we have also developed user level software to demonstrate how the interface can be used. This software consists of a library, called libpfm, and a monitoring tool called pfmon.

Here is a summary of what each component provides:

perfmon2:

This is the performance interface which gives full access to the PMU.

libpfm:

This is a helper library which can be used by tools to setup the parameters to the kernel perfmon interface. The library encapsulates all the PMU model specific information, such as event encodings and constraints. The library is not required to use the kernel interface. The library currently supports all existing Itanium PMU models.

pfmon:

This is a simple monitoring tool which can monitor unmodified programs or the entire system (UP and SMP). With pfmon, you can collect event counts or create sampling sessions. The tool currently supports all existing Itanium PMU models.