On Thu, 7 May 2026 14:08:12 GMT, Markus Grönlund <[email protected]> wrote:
>> test/jdk/jdk/jfr/jvm/TestJdkEpochThrottle.java line 92: >> >>> 90: validate(secondRecording, 3); >>> 91: secondRecording.close(); >>> 92: validate(firstRecording, 9); >> >> I haven't seen a test that has two recordings in use at the same time. The >> event isn't explicitly enabled for secondRecording, is the nesting relevant >> here? Also does the stop + start guaranteed to bump the epoch? > > We have many JFR tests that start multiple, nested recordings. Since a > recording cannot turn off an event enabled by another recording, and there is > only one recording stream in total, the second recording inherits the enabled > event (the event setting is a union of 1 v 0), which means the event is also > enabled for the subsequent recording. > > Start and stop are both implemented as rotations, and rotations use a > stop-the-world safepoint to bump the epoch. I wasn't sure how it worked with concurrent recordings so your message is useful, thanks. I will note that I did read through the Recording API docs but couldn't find anything obvious that documents this. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/30922#discussion_r3202635148
