RFR: 8213966: The ZGC JFR events should be marked as experimental
erik.gahlin at oracle.com
Wed Nov 28 20:15:17 UTC 2018
Could I have a review of a fix that will mark the ZGC events for JFR as
The experimental attribute was created so that JVM developers could add
events more freely to HotSpot without the burden to write unit tests or
commit to a particular event design. Experimental events are not shown
in JMC by default, but can be made visible in the Preference dialog. See
the following picture.
As part of this change, I also moved the Z Page Allocation event into
JVM / GC / Detailed category with the other ZGC events. It seemed more
appropriate, as the Java category is meant for events that are more
close to the Java application when doing troubleshooting.
The experimental=true attribute can be removed/changed in a future
release. At that time, it may make sense to revisit the event layout.
Perhaps break up the Z Statistics event into more fine-grained events
with proper labels and descriptions. Marking the ZGC events as
experimental also means the events won't require special treatment in
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