RFR: 8347489: RISC-V: Misaligned memory access with COH [v4]

[Fei Yang]

On Wed, 15 Jan 2025 14:20:21 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> Fei Yang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains six additional commits since the last revision:
>> 
>>  - Merge branch 'master' into JDK-8347489
>>  - Comment
>>  - Fix assertions
>>  - Add assertions
>>  - Comment
>>  - 8347489: RISC-V: Misaligned memory access with COH
>
>> -XX:+UseParallelGC -XX:+AlwaysPreTouch -Xms8g -Xmx8g
> 
> I guess the RVV is disabled by default? Will we also address the similar issue when RVV enabled?

> > @Hamlin-Li Thanks for the suggestions. I have updated accordingly. Note that base_offset is 12 and 16 bytes respectively w/wo COH. And I have also added some specjbb2005 scores in PR description for reference.
> 
> Thank you posting the data! As G1 is the default one, can you run the specjbb with G1? And it would be good to list both critial and max value for specjbb. BTW, there are also some string comparison tests in jmh, e.g. StringCompareToDifferentLength and so on.

The purpose of using ParallelGC for the test is to minimize the GC noise. I have also updated SPECjbb2005 score under G1GC in PR description for reference. Note that SPECjbb2005 score means bops (business operations per second). I will update SPECjbb2015 later which has max and critical jops. Thanks.

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PR Comment: https://git.openjdk.org/jdk/pull/23053#issuecomment-2595197104