On Thu, 5 Nov 2020 14:36:44 GMT, Erik Österlund <eosterl...@openjdk.org> wrote:
>> Ok, so there were many test failures with other approaches. Having GC >> trigger the posting was the most reliable way to post the events when the >> tests (and presumably the jvmti customers) expected the events to be posted. >> We could revisit during event disabling if a customer complains about GC >> pause times. > > The point of this change was not necessarily to be lazy about updating the > tagmap, until someone uses it. The point was to get rid of the last annoying > serial GC phase. Doing it all lazily would certainly also achieve that. But > it would also lead to situations where no event is ever posted from GC to GC. > So you would get the event 20 GCs later, which might come as a surprise. It > did come as a surprise to some tests, so it is reasonable to assume it would > come as a surprise to users too. And I don't think we want such surprises > unless we couldn't deal with them. And we can. Kim's change to post the events from the service thread or before other JVMTI operations removes posting events from the gc_notification, which was the objection. ------------- PR: https://git.openjdk.java.net/jdk/pull/967
