pmapi

pmapi is a command-line utility and library for interacting with the Performance Monitoring Unit (PMU) on Linux systems. It provides a way to access and interpret hardware performance counter data, allowing developers and system administrators to profile the performance of applications and the operating system.

The primary function of pmapi is to abstract away the complexities of direct PMU hardware access. It exposes a consistent interface that can be used to read various performance events, such as CPU cycles, cache misses, instruction retired, and branch mispredictions. These events can be used to identify performance bottlenecks, optimize code, and understand system behavior at a granular level.

pmapi supports a wide range of hardware architectures and PMU implementations, making it a versatile tool for performance analysis across different systems. It can be used to sample events at regular intervals or to count specific events over a defined period. The collected data can then be exported in various formats for further analysis with other tools.

In addition to its command-line interface, pmapi also offers a library that can be integrated into custom applications. This allows developers to embed performance monitoring capabilities directly into their software, enabling real-time performance feedback and diagnostics. The library provides functions for initializing the PMU, configuring event sets, starting and stopping measurements, and retrieving event counts.

pmapi is often used in conjunction with other performance analysis tools like perf, as well as in high-performance computing environments. Its ability to provide detailed hardware performance metrics makes it an invaluable resource for anyone seeking to deeply understand and improve the efficiency of their software and systems.