Chapter 1. Introduction

Table of Contents

1. OProfile legacy profiling mode
2. OProfile perf_events profiling mode
3. OProfile event counting mode
4. Applications of OProfile
4.1. Support for dynamically compiled (JIT) code
4.2. No support for virtual machine guests
5. System requirements
6. Internet resources
7. Installation
8. Uninstalling OProfile

This manual applies to OProfile version 1.2.0. OProfile is a set of performance monitoring tools for Linux 2.6 and higher systems, available on a number of architectures. OProfile provides the following features:

OProfile is capable of monitoring native hardware events occurring in all parts of a running system, from the kernel (including modules and interrupt handlers) to shared libraries to binaries. OProfile can collect event information for the whole system in the background with very little overhead. These features make it ideal for monitoring entire systems to determine bottle necks in real-world systems.

Many CPUs provide "performance counters", hardware registers that can count "events"; for example, cache misses, or CPU cycles. OProfile can collect profiles of code based on the number of these occurring events: repeatedly, every time a certain (configurable) number of events has occurred, the PC value is recorded. This information is aggregated into profiles for each binary image. Alternatively, OProfile's event counting tool can collect simple raw event counts.

1. OProfile legacy profiling mode

Prior to release 1.0, OProfile included a profiling tool consisting of the opcontrol shell script, the oprofiled daemon, and the attendant oprofile kernel driver. This "legacy profiler" was deprecated in release 0.9.8 with the introduction of the operf profiling tool (see Section 2, “OProfile perf_events profiling mode”). Some older architectures/platforms do not support the use of operf. For those cases, oprofile users should install release 0.9.9, which is the last release to include the legacy profiler.