JDK Mission Control and Flight Recorder provide a low overhead tool for recording information about the Java Virtual Machine and applications running on it. It records various types of data like CPU and memory profiling and can be controlled through command line, APIs, and the JDK Mission Control application. The data recorded is typically around 2 megabytes per minute and can help troubleshoot performance and debugging issues.

1. JDK Mission Control &
Flight Recorder
Jean-Philippe Bempel
@jpbempel

2. ● Built into the JVM
● Records information about the JVM and the application
● Low overhead / High performance
● APIs available to record custom information
● Can be used to solve a range of different problems
● Open sourced by Oracle in OpenJDK 11
● Backport to OpenJDK 8 well underway!
Data Flight Recorder for the JVM

3. Comprehensive Tool Chain
● Control the Flight Recorder
○ Command line parameters
○ POJO API
○ JMX API
○ jcmd (tool in the JDK)
○ JDK Mission Control
● Add custom data
○ Java API (in the JDK)
○ JDK Mission Control (agent)
○ Third party integrations (Open Tracing, Brave etc)
● Use the data
○ JDK Mission Control (application)
○ JDK Mission Control (core libraries)
○ jfr (tool in the JDK)

4. ● CPU Profiling
● Allocation Profiling
● Thread Latency Profiling
● GC
● Compiler
● Memory Leak Profiler
● ...and much more
Size is typically about 2 megs per minute (app. 100k events)
Different Kinds of Data

5. ● High performance recording engine
● Events recorded into thread buffers
● When full, copied into global buffer
● Can be configured to emit to disk…
● …or to keep on overwriting/reusing
the buffer
Flight Recorder Innards

6. Demo

7. ● Flight Recorder API programmer’s guide
● Running Flight Recorder (Oracle)
● JFR events built-in the JVM
● JMC GitHub repo
● JMC tutotrial
● JMC binaries (AdoptOpenJDK)
● Marcus Hirt’s blog
References

8. Thank You!
Jean-Philippe Bempel
@jpbempel