RFR: 8280396: G1: Full gc mark stack draining should prefer to make work available to other threads [v4]

[Albert Mingkun Yang]

On Mon, 24 Jan 2022 16:53:51 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Hi all,
>> 
>>   can I have reviews for this change that fixes a significant performance problem with g1 full gc marking when the overflow queue is in use? Basically this case causes the threads never share their work from the overflow queue, resulting in very bad parallelization in some cases.
>> 
>> This is a problem that has been fixed already in [JDK-8152438](https://bugs.openjdk.java.net/browse/JDK-8152438), but when looking at this code on g1 and parallel full gc, they both showed that issue.
>> 
>> This is the change for g1.
>> 
>> The CR shows some numbers how bad this can be.
>> 
>> Thanks,
>>   Thomas
>
> Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Comments, cleanup

Marked as reviewed by ayang (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/7175