RFR: 8280450: Add task queue printing to STW Full GCs

[Albert Mingkun Yang]

On Fri, 28 Jan 2022 09:58:03 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

> Hi all,
> 
>   please review this change that adds task queue statistics printing after full gc marking. This helps diagnosing performance issues there.
> 
> Testing: compilation, gha, local testing (all new code is guarded by `TASKQUEUE_STATS` so not compiled in by default)
> 
> Thanks,
>   Thomas

I feel `TASKQUEUE_STATS` and the fact that there are two task queues are too low-level in this context. However, I am not sure hiding them behind a method is definitely better either. Pragmatically, we can keep it this way for now and refine it latter if needed.

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

Marked as reviewed by ayang (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/7264