perf-cpp

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直接从 C++ 应用程序中轻量级记录和采样性能计数器,针对特定代码段。

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工具介绍

直接从 C++ 应用程序中轻量级记录和采样性能计数器,针对特定代码段。

perf-cpp: Hardware Performance Monitoring for C++

Quick Start | Building | Documentation | System Requirements

perf-cpp lets you profile specific parts of your code, not the entire program.

Tools like Linux Perf, Intel® VTune™, and AMD uProf profile everything: application startup, configuration parsing, data loading, and all your helper functions. perf-cpp is different: place start() and stop() around exactly the code you want to measure. Profile one sorting algorithm, or count cache misses in a single hash table lookup. Wrap two memory allocators separately, and you get a fair comparison.

Features

Built around Linux's perf subsystem, perf-cpp supports counting and sampling hardware events for specific code blocks:

Record hardware events like perf stat, but only around the code you care about (documentation)
Calculate metrics like cycles per instruction or cache miss ratios from the counters (documentation)
Read counter values without stopping the counter for low-overhead measurements in tight loops (documentation)
Sample instructions and memory accesses like perf record and perf mem record, but targeted at specific functions (documentation)
Export and visualize results: write samples to CSV, generate flame graphs, or correlate memory accesses with specific data structures
Mix built-in events like cycles and cache misses with processor-specific PMU events (documentation)

See the examples and full documentation for details.

Quick Start

Record Hardware Event Statistics

…

cpp #include

// Create the sampler auto sampler = perf::Sampler{};

// Specify when a sample is recorded: every 50,000th cycle sampler.trigger("cycles", perf::Period{50000U});

// Specify what data is included in a sample: time, CPU ID, instruction sampler.values() .timestamp(true) .cpu_id(true) .logical_instruction_pointer(true);

// Run the workload sampler.start(); code_to_profile(); // [!NOTE]

See the sampling guide for what data you can record. Also check out the sampling on multiple CPUs/threads guide for parallel sampling.

Building

perf-cpp can be built as a static or shared library.

bash

git clone https://github.com/jmuehlig/perf-cpp.git
cd perf-cpp
cmake . -B build
cmake --build build

[!NOTE] See the building guide for CMake integration and build options.

Documentation

The full documentation is available at jmuehlig.github.io/perf-cpp.

System Requirements

GCC 11 or newer, or Clang 14 or newer, with C++17 support.
CMake version 3.10 or higher.
Linux Kernel 4.0 or newer (some features require a newer kernel).
perf_event_paranoid setting: Adjust as needed to allow access to performance counters (see the perf paranoid documentation).
Python 3, if you use processor-specific hardware event generation.

Contributing

Contributions are welcome. Open an issue or submit a pull request.

To build and run the tests:

bash

cmake . -B build -DBUILD_TESTS=ON
cmake --build build --target tests
./build/bin/tests

[!NOTE] Most tests require access to hardware performance counters via perf_event_open. If your system restricts access (e.g., in containers or VMs), some tests will fail. See the perf paranoid documentation.

For questions or feedback: [email protected].

Related Projects

Other profiling tools:

PAPI monitors CPU counters, GPUs, I/O, and more.
Likwid is a set of command-line tools for benchmarking with an extensive wiki.
PerfEvent is a lightweight wrapper for performance counters.
Intel's Instrumentation and Tracing Technology lets you control Intel VTune Profiler from your code.
Want to go lower-level? Use perf_event_open directly.