Summary

Backport of JFR infrastructure, tooling and APIs to OpenJDK8u

Problem

We would like to request a compatibility review for the backport work we are doing regarding the JFR project from later version of OpenJDK to OpenJDK8u.

We believe that most of the work is hidden from users. The API being added are not part of the specification for Java8 (reside under the jdk.jfr namespace introduced in Java 11) and the command line options are in the "-XX" flag that signal extra/unsupported options.

Currently, the work for the backport is done in an incubator repository, we believe the repository contains now most of the changes necessary and is suitable for a review:

http://hg.openjdk.java.net/jdk8u/jdk8u-jfr-incubator/

Specification

• Addition of libraries in the jdk.jfr namespace

  • This is being worked currently as a separate jfr.jar that users will have to link specifically. An empty implementation is also being worked on for compatibility mode.

• The jfr tool will be introduced in bin/

• The MBean interface to control JFR will be introduced

• Extra command line options will be introduced in the java lancher. like:

-XX:+FlightRecorder -XX:StartFlightRecording -XX:FlightRecorderOptions

If Flight recorder is present, the behavior is the same as the current Oracle 8 JDK, otherwise the behavior does not change.

The jdk.jfr API is optional.