RFR (S): 8248221: G1: millis_since_last_gc updated at wrong time
thomas.schatzl at oracle.com
Thu Jun 25 08:04:09 UTC 2020
can I have reviews for this change that fixes the location at which
the millis_since_last_gc timestamp is updated.
The spec of the only user in sun.rmi.transport.GC.maxObjectInspectionAge
* Returns the maximum <em>object-inspection age</em>, which is the number
* of real-time milliseconds that have elapsed since the
* least-recently-inspected heap object was last inspected by the garbage
Currently we do that update only at young gc, which is wrong. We should
do that if/when a complete liveness analysis cycle has finished instead,
i.e. end of marking/end of full gc.
I did some testing using the TestMillisSinceLastGC.java jtreg test in
http://cr.openjdk.java.net/~tschatzl/8248221/webrev.test/. As expected,
it failed for G1 but all other GCs tested there pass (Epsilon will
probably also fail, because it never does any gc so I did not even try).
However the test intrinsically depends on timing i.e. the duration
between some GC and checking the CollectedHeap::millis_since_last_gc()
result, so I did not add it to this webrev. While in my ci testing it
did not fail, I deemed it too risky to add.
I also eyeballed that the output is still reasonable (i.e. no unit
problem introduced by 8165501) using its log output for all affected
Depends on 8243974.
tier1-5 with 8243974 and 8165501, manual testing as described above.
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