RFR: 8284686: Interval of < 1 ms disables ExecutionSample events

[Johannes Bechberger]

On Wed, 13 Apr 2022 12:45:15 GMT, Erik Gahlin <egahlin at openjdk.org> 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.
>
> You mentioned elsewhere that it fails in debug mode, I think it should work there as well. 
> 
> Did you try your change with tests in test/jdk/jdk/jfr? Might make sense to write a test, or add your use case to an existing test.
> 
> The documentation should say "1 ms" instead of "1ms". The latter is only used at command-line. 
> 
> You are changing the specification, so a CSR might be needed as well.

@egahlin is my PR fine?

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