RFR: 8003216: Add JFR event indicating explicit System.gc() cal
stefan.johansson at oracle.com
Wed Feb 26 13:21:16 UTC 2020
> 26 feb. 2020 kl. 13:56 skrev Per Liden <per.liden at oracle.com>:
> Hi Erik,
> On 2020-02-26 13:50, Erik Gahlin wrote:
>> Could I have a review of a JFR event that is emitted when System.gc() is called.
>> Purpose is to collect the stack trace. It is not sufficient with the cause field that the GarbageCollection event has today.
> 489 EventSystemGC event;
> 490 event.commit();
> 491 Universe::heap()->collect(GCCause::_java_lang_system_gc);
> Don't you want the commit() call after the call to collect(), to get the timing right?
I was thinking the same thing, could also be nice to have the GC-id associated with the event to make it easy to match it to GC-logs and other GC-events. Not sure how to easily get the GC-id though, since it’s not set at the time we commit the event.
I guess if the event has the correct span with timestamps it will be easy to figure out which other events are associated with it, even without the GC-id.
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