Affects Version/s: 1.15.2, 20w06a, 20w07a, 20w09a
Fix Version/s: None
Eclipse OpenJ9 VM AdoptOpenJDK (build openj9-0.18.0, JRE 13 Linux amd64-64-Bit)
Intel Xeon (Skylake, IBRS) @ 2x 2.3GHz
2GB Ram per server
Since 1.14/1.15, CPU usage has increased by a very large amount. In 1.13, usage was around 5% with nobody online, but in 1.15+ an entire core is being used. I tested with a fresh instance on 1.13, 1.15 and 1.16 snapshot 20w06a with the vanilla server jar (1.14 not tested). Even with more cores and ram this is still an issue.
I have attached files showing the difference, at the start it maxes out (as expected) and then comes to its resting cpu usage. As you can see 1.13 uses very little compared to the 1.16 server.