Generate Java flame graphs using async-profiler

Overview

Async-profiler is a low-overhead sampling profiler for JVM applications. It can capture CPU usage, memory allocations, and lock events to generate flame graphs and detailed stack traces.

This tool is well-suited for production environments due to its minimal runtime impact. In this section, you’ll install and run async-profiler to analyze performance on your Tomcat instance under benchmark load.

Install async-profiler

Download and extract the latest release:

    

        
        
wget -c https://github.com/async-profiler/async-profiler/releases/download/v4.0/async-profiler-4.0-linux-arm64.tar.gz
tar xzf async-profiler-4.0-linux-arm64.tar.gz

    

Run the profiler

Navigate to the profiler binary directory:

    

        
        
cd async-profiler-4.0-linux-arm64/bin

    

Run async-profiler against the Tomcat process:

    

        
        
./asprof -d 10 -f profile.html $(jps | awk /Bootstrap/'{print $1}')

    

Alternatively, if you already know the process ID (PID):

    

        
        
./asprof -d 10 -f profile.html ${tomcat_process_id}

    

• -d 10 sets the profiling duration to 10 seconds

• -f profile.html specifies the output file

View the flame graph

Open the generated profile.html file in a browser to view your Java flame graph:

Java flame graph built using async-profiler