RFR: 8307058: Implementation of Generational ZGC [v2]

[Stefan Karlsson]

On Wed, 3 May 2023 18:54:24 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> Stefan Karlsson has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fix PPC build after 8305668
>
> test/jdk/ProblemList-generational-zgc.txt line 27:
> 
>> 25: #
>> 26: # List of quarantined tests for testing with Generational ZGC.
>> 27: #
> 
> Are the tests in `test/jdk/sun/tools/jhsdb/` not failing?

It seems like these tests are only run with all GCs at the end of the development cycle. I've run them manually and verified that these tests fail as well. I'm going to problem list them.

That run also revealed that jstat doesn't like when we report the initial capacity of the old generation as zero. See the calculation in:
src/jdk.jcmd/share/classes/sun/tools/jstat/resources/jstat_options

  column {
    header "^O^"        /* Old Space - Percent Used */
    data (1-((sun.gc.generation.1.space.0.capacity - sun.gc.generation.1.space.0.used)/sun.gc.generation.1.space.0.capacity)) * 100
    align right
    scale raw
    width 6
    format "0.00"
  }


I can work around the test problem by faking the capacity to be non-zero, but that's not a pretty solution IMO.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13771#discussion_r1184285686