Java Reference
In-Depth Information
There are other displays like this—for threads, I/O, and system events—but for the most
part, these displays simply provide nice views into the actual events in the JFR recording.
Overview of JFR events
JFR produces a stream of events that are saved as a recording. The displays seen so far
provide views of those events, but the most powerful way to look at the events is on the
Event panel itself, as seen in Figure 3-12 .
Figure 3-12. Java Flight Recorder Event panel
The events to display can be filtered in the lefthand panel of this window; here, only the
application-level events are selected. Be aware that when the recording is made, only certain
kinds of events are included in the first place: at this point, we are doing postprocessing fil-
tering (the next section will show how to filter the events included in the recording).
Within the 66-second interval in this example, the application produced 10,612 events from
the JVM and 1,536 events from the JDK libraries, and the six event types generated in that
period are shown near the bottom of the window. I've already discussed why the thread-park
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