Summary

Add the option 'report-on-exit' to -XX:StartFlightRecording so that summary reports, aka 'jfr views', are written when the JVM exits.

Problem

To get a summary view from the 'jfr' tool, users must first specify a filename with -XX:StartFlightRecording to dump a recording file to disk when the JVM exits. Next, they must run the 'jfr' tool against that recording file to display a summary, such as the hot-methods view. Finally, they must delete the file unless they want to keep it for other things.

Example workflow:

$ java -XX:StartFlightRecording:filename=dump.jfr ...
$ jfr view hot-methods
$ rm dump.jfr

This process is unnecessarily cumbersome.

Solution

Allow users to specify the name of the 'jfr view' directly with -XX:StartFlightRecording to have it printed automatically when the JVM exits. It eliminates the need to specify a filename, run a separate tool, and delete the file afterward.

Example workflow:

$ java -XX:StartFlightRecording:report-on-exit=hot-methods ...

If JFR records data to memory (which occurs when disk=false is specified), generating the report is impossible unless the data is first copied to disk. Although it is technically possible to implement a mechanism to copy the data from memory to disk before generating the report, this would override the user's explicit choice, so -XX:StartFlightRecording will not accept report-on-exit in combination with disk=false. Instead, the JVM will fail to start and print an error message.

Specification

diff --git a/src/java.base/share/man/java.md b/src/java.base/share/man/java.md
index 32280f2c516..987dbf64159 100644
--- a/src/java.base/share/man/java.md
+++ b/src/java.base/share/man/java.md
@@ -1447,6 +1447,12 @@ ## Advanced Runtime Options for Java
         the potential leaking object was allocated is included in the
         information collected.

+    `report-on-exit=`*identifier*
+    :   Specifies the name of the view to display when the Java Virtual Machine
+        (JVM) shuts down. This option is not available if the disk option is set
+        to false. For a list of available views, see `jfr help view`. By default,
+        no report is generated.
+
     `settings=`*path*
     :   Specifies the path and name of the event settings file (of type JFC).
         By default, the `default.jfc` file is used, which is located in

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