ZGC AArch64 hang on SPECjbb2015

[逯晓威(峰风)]

Hi, I have tested zgc on jdk-15-GA and found occasionally SPECjbb2015 hangs when it is about to shut down. This is quite hard to reproduce, one out of 20 iterations probably. Since it only reproduces during shut down, I prefer to use "preset" mode to run SPECjbb to save time.
jdk-15-GA/bin/java -XX:+UseZGC -Xmx10g -Dspecjbb.controller.type=PRESET -Dspecjbb.controller.preset.ir=20000 -Dspecjbb.controller.preset.duration=60000 -jar specjbb2015.jar -m COMPOSITE
And SPECjbb log is as follow:
<Tue Jan 04 03:06:13 EST 2022> org.spec.jbb: Failed to stop executor service java.util.concurrent.ForkJoinPool at 9d2cbbc[Terminating, parallelism = 160, size = 2, active = 0, running = 2, steals = 40255, tasks = 0, submissions = 0], trying again
<Tue Jan 04 03:06:14 EST 2022> org.spec.jbb: Failed to stop executor service java.util.concurrent.ForkJoinPool at 9d2cbbc[Terminating, parallelism = 160, size = 2, active = 0, running = 2, steals = 40255, tasks = 0, submissions = 0], trying again

This seems quite similar to a previous issue: https://bugs.openjdk.java.net/browse/JDK-8214285, but on AArch64 other than Skylake. In addition, JDK-8214285 has been solved in jdk12, but we reproduced this issue on jdk-13.0.2+8 and jdk-14.0.2+12

Regards,Xiaowei Lu