Pyroscope Java agent

The Java profiling agent for Pyroscope.io. Based on async-profiler.

Distribution

The agent is distributed as a single JAR file pyroscope.jar. It contains native async-profiler libraries for:

• Linux on x64;
• Linux on x86;
• Linux on AArch64;
• Linux on ARM;
• MacOS on x64.

Downloads

Visit releases page to download the latest version of pyroscope.jar

Usage

To run a Java application with the agent:

java -javaagent:pyroscope.jar -jar app.jar

On the startup, the agent deploys the native corresponding library into /tmp/${username}-pyroscope/.

Configuration

The agent is configured using environment variables.

• PYROSCOPE_APPLICATION_NAME: The application name used when uploading profiling data. Generated if not provided.
• PYROSCOPE_PROFILING_INTERVAL: Sets the profiling interval in nanoseconds or in other units, if N is followed by ms (for milliseconds), us (for microseconds), or s (for seconds). See async-profiler documentation for details. The default is 10ms.
• PYROSCOPE_UPLOAD_INTERVAL: Sets the profiling interval for uploading snapshots. The default is 10s.
• PYROSCOPE_PROFILER_EVENT: Sets the profiling event. See async-profiler documentation for details. The supported values are cpu, alloc, lock, wall, and itimer. The defaults is itimer.
• PYROSCOPE_LOG_LEVEL: The log level: debug, info, warn, error. The default is info.
• PYROSCOPE_SERVER_ADDRESS: The address of the Pyroscope server. The default is http://localhost:4040.
• PYROSCOPE_AUTH_TOKEN: The authorization token used to upload profiling data.

JFR format and multiple event support

Starting with version v0.5.0 JFR format is (partially) supported to be able to support multiple events (JFR is the only output format that supports multiple events in async-profiler). It currently supports the following events:

• jdk.ExecutionSample (supported in pyroscope-java >= 0.5.0 and pyroscope >= 0.13.0), used for CPU sampling events (itimer, cpu, wall).
• jdk.ObjectAllocationInNewTLAB (supported in pyroscope-java >= 0.5.0 and pyroscope >= 0.14.0), used for alloc sampling.
• jdk.ObjectAllocationOutsideTLAB (supported in pyroscope-java >= 0.5.0 and pyroscope >= 0.14.0), used for alloc sampling.

There are several environment variables that define how multiple event configuration works:

• PYROSCOPE_FORMAT sets the profiler output format. The default is collapsed, but in order to support multiple formats it must be set to jfr.
• PYROSCOPE_PROFILER_EVENT sets the profiler event. With JFR format enabled, this event refers to one of the possible CPU profiling events: itimer, cpu, wall. The default is itimer.
• PYROSCOPE_PROFILER_ALLOC sets the allocation threshold to register the events, in bytes (equivalent to --alloc= in async-profiler. The default value is 0, which means that allocation profiling is disabled. Setting it to 1 will register all the events.

Building

If you want to build the agent JAR yourself, from this repo run:

./gradlew shadowJar

The file will be in agent/build/libs/pyroscope.jar.