RFR: 8284686: Interval of < 1 ms disables ExecutionSample events [v6]

[Jaroslav Bachorik]

On Thu, 5 May 2022 11:02:09 GMT, Johannes Bechberger <duke at openjdk.java.net> wrote:

>> Fixes the issue by rounding the period interval to the next full millisecond larger than zero.
>> 
>> The following from the bug report works now:
>> 
>> java -XX:StartFlightRecording=filename=flight.jfr,jdk.ExecutionSample#period=999us CLASS_FILE; jfr print --events jdk.ExecutionSample flight.jfr
>> 
>> It considers the period to be `1ms`, producing the recording as expected.
>
> Johannes Bechberger has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Add TestShortPeriod
>  - Remove TestPeriodSetting

test/jdk/jdk/jfr/api/recording/event/TestShortPeriod.java line 63:

> 61:         try (var r = new RecordingStream()) {
> 62:             r.enable(EventNames.JVMInformation).withPeriod(Duration.ofNanos(1));
> 63:             r.onEvent(e -> r.close());

What happens when the event is, in fact, disabled?
The test will run forever, right?

Could you rather use something like `CountDownLatch` which will get decremented in `onEvent()` handler and the test method would wait for that latch for at most N milliseconds - failing when the wait times out?

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PR: https://git.openjdk.java.net/jdk/pull/8183