The JDK Flight Recorder is being made available for OpenJDK 8 thanks to work to backport it by open source contributors. The recorder can be used to monitor JVM performance without incurring high overheads, and was already available for OpenJDK 11.
The backport is a collaboration between Red Hat, Alibaba, Azul and Datadog, and means developers using OpenJDK 8 will be able to benefit from the data JDK Flight Recorder can provide.
The JDK Flight Recorder grew out of Oracle's Java Flight Recorder. This was a commercial add-on for the Oracle JDK that was open sourced at the same time as Java Mission Control. Java Flight Recorder started life as the JRockit Flight Recorder, and was only aimed at improving the JVM. When Oracle acquired Java as part of the Sun Microsystems deal, it was renamed Java Flight Recorder, then renamed JDK Flight Recorder when it was open sourced.
JDK Flight Recorder is incorporated as part of the JDK so is accurate in its performance monitoring, and has a low overhead of around 2 percent. It can either be used as the automated recorder inside the JVM, or there's a Mission Control console that you run on a different system to work with the automated internal recorder to evaluate the results or to create performance snapshots.
JDK Flight Recorder collects data about the running threads, GC cycles, locks, sockets, and memory usage along with a variety of other data. It also offers advanced garbage collection analysis, including what garbage was collected and which threads discarded it in the first place. This provides useful information for improving performance.
The backport is keeping the same interfaces and implementation as that in OpenJDK 11, and is fully compatible. Some events such as Module related events won't be available, but other than that the API and tools work exactly the same. To use OpenJDK 8 with JFR you'll need to build the JDK available in the repository mentioned in the More Information box below.
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