Avoid 0 duration GC event times #1170
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We noticed
:dist-avgunder 1ms for ZGC andgetDurationis in milliseconds, so we must be regularly seeing events that start and end in the same millisecond:https://github.com/openjdk/jdk/blob/3b283543c33df8c225e10b9186b7bc3cefd1a347/src/jdk.management/share/classes/com/sun/management/GcInfo.java#L140-L147
There are few other problems with these metrics and the concurrent garbage collectors, but I'm intentionally avoiding looking at those because we expect to have better ways of measuring GC overhead/pressure in upcoming releases.