[jdk18] RFR: 8273107: RunThese24H times out with "java.lang.management.ThreadInfo.getLockName()" is null [v4]

[Daniel D.Daugherty]

> RunThese24H sometimes times out with a couple of error msgs:
> - "java.lang.management.ThreadInfo.getLockName()" is null
> - ForkJoin common pool thread stuck
> 
> The '"java.lang.management.ThreadInfo.getLockName()" is null' error msg was
> due to RunThese's use of an older JCK test suite which has since been fixed.
> 
> The 'ForkJoin common pool thread stuck' failure mode is likely due to a thread
> spending a lot of time in ObjectSynchronizer::monitors_iterate() due to a
> VM_ThreadDump::doit() call. I say "likely" because I've never been able to
> reproduce this failure mode in testing outside of Mach5. With the Mach5
> sightings, all we have are thread dumps and core files and not a live process.
> 
> The VM_ThreadDump::doit() call is trying to gather owned monitor information
> for all threads in the system. I've seen sightings of this failure mode with > 2000
> threads. I've also seen passing runs with > 1.7 million monitors on the in-use list.
> Imagine searching a larger in-use list for > 2000 threads. It just doesn't scale.

Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:

  Rename 'jt_count' to 'key_count'.

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk18/pull/25/files
  - new: https://git.openjdk.java.net/jdk18/pull/25/files/d1ca83e7..d980013e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk18&pr=25&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk18&pr=25&range=02-03

  Stats: 6 lines in 2 files changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk18/pull/25.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk18 pull/25/head:pull/25

PR: https://git.openjdk.java.net/jdk18/pull/25