The following test failed in the JDK15 CI:

serviceability/tmtools/jstat/GcTest02.java

Here's a snippet from the log file:

#section:main
----------messages:(5/542)----------
command: main -XX:+IgnoreUnrecognizedVMOptions -XX:-VerifyDependencies -XX:+UsePerfData -XX:MaxNewSize=4m -XX:MaxHeapSize=128M -XX:MaxMetaspaceSize=128M GcTest02
reason: User specified action: run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-VerifyDependencies -XX:+UsePerfData -XX:MaxNewSize=4m -XX:MaxHeapSize=128M -XX:MaxMetaspaceSize=128M GcTest02
Mode: othervm [/othervm specified]
Additional options from @modules: --add-modules java.base --add-exports java.base/jdk.internal.misc=ALL-UNNAMED
elapsed time (seconds): 49.556
----------configuration:(4/115)----------
Boot Layer
  add modules: java.base
  add exports: java.base/jdk.internal.misc ALL-UNNAMED

----------System.out:(6/712)*----------
[2020-03-11T14:19:18.917322100Z] started process 18104 [c:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+14-547\\windows-x64-debug.jdk\\jdk-15\\fastdebug\\bin\\jstat.exe, -gc, 30564] with out/err redirected to '.\\out.5121244724749317836.txt' and '.\\err.5121244724749317836.txt'
[2020-03-11T14:19:21.336348500Z] process 18104 finished with exit code = 0
Process output: Exit code: 0
stdout: S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT CGC CGCT GCT
 0.0 0.0 0.0 1024.0 4096.0 0.0 125952.0 530.5 5888.0 5307.3 512.0 244.1 1 0.017 0 0.000 0 0.000 0.017
stderr:
----------System.err:(16/1031)----------
java.lang.RuntimeException: S1U > S1C (utilization > capacity)
at utils.JstatResults.assertThat(JstatResults.java:172)
at utils.JstatGcResults.assertConsistency(JstatGcResults.java:89)
at GarbageProducerTest.run(GarbageProducerTest.java:50)
at GcTest02.main(GcTest02.java:45)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:832)

JavaTest Message: Test threw exception: java.lang.RuntimeException: S1U > S1C (utilization > capacity)
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.RuntimeException: S1U > S1C (utilization > capacity)
----------rerun:(56/6577)*----------