async-profiler

Async-profiler

This project is a low overhead sampling profiler for Java that does not suffer from the Safepoint bias problem. It features HotSpot-specific API to collect stack traces and to track memory allocations. The profiler works with OpenJDK and other Java runtimes based on the HotSpot JVM.

Unlike traditional Java profilers, async-profiler monitors non-Java threads (e.g., GC and JIT compiler threads) and shows native and kernel frames in stack traces.

What can be profiled:

• CPU time
• Allocations in Java Heap
• Native memory allocations and leaks
• Contended locks
• Hardware and software performance counters like cache misses, page faults, context switches
• and more.

See our 3 hours playlist to learn about more features.

Download

Stable release: 4.5

• Linux x64: async-profiler-4.5-linux-x64.tar.gz
• Linux arm64: async-profiler-4.5-linux-arm64.tar.gz
• macOS arm64/x64: async-profiler-4.5-macos.zip
• Profile converters: jfr-converter.jar

Nightly builds

The most recent binaries corresponding to the latest successful commit in master.

For a build corresponding to one of the previous commits, go to Nightly Builds, click the desired build and scroll down to the artifacts section. These binaries are kept for 30 days.

Quick start

In a typical use case, profiling a Java application is just a matter of a running asprof with a PID of a running Java process.

$ asprof -d 30 -f flamegraph.html <PID>

The above command translates to: run profiler for 30 seconds and save results to flamegraph.html as an interactive Flame Graph that can be viewed in a browser. Find more details in the Getting started guide.

Building

Build status

Minimum requirements

• make
• GCC 7.5.0+ or Clang 7.0.0+
• Static version of libstdc++ (e.g. on Amazon Linux 2023: yum install libstdc++-static)
• JDK 11+

How to build

Make sure gcc, g++ and java are available on the PATH. Navigate to the root directory with async-profiler sources and run make. async-profiler launcher will be available at build/bin/asprof.

Other Makefile targets:

• make test - run unit and integration tests;
• make release - package async-profiler binaries as .tar.gz (Linux) or .zip (macOS).

Supported platforms

	Officially maintained builds	Other available ports
Linux	x64, arm64	x86, arm32, ppc64le, riscv64, loongarch64
macOS	x64, arm64

Documentation

Basic usage

• Getting Started
• Profiler Options
• Profiling Modes
• Integrating async-profiler
• Profiling In Container

Profiler output

• Output Formats
• FlameGraph Interpretation
• JFR Visualization
• Converter Usage
• Heatmap

Advanced usage

• CPU Sampling Engines
• Stack Walking Modes
• Advanced Stacktrace Features
• Profiling Non-Java Applications

Troubleshooting

For known issues faced while running async-profiler and their detailed troubleshooting, please refer here.