RFR: 8329331: Intrinsify Unsafe::setMemory [v25]

Sat Apr 20 20:48:31 UTC 2024

On Sat, 20 Apr 2024 19:09:43 GMT, Scott Gibbons <sgibbons at openjdk.org> wrote:

>> This code makes an intrinsic stub for `Unsafe::setMemory` for x86_64.  See [this PR](https://github.com/openjdk/jdk/pull/16760) for discussion around this change.
>> 
>> Overall, making this an intrinsic improves overall performance of `Unsafe::setMemory` by up to 4x for all buffer sizes.
>> 
>> Tested with tier-1 (and full CI).  I've added a table of the before and after numbers for the JMH I ran (`MemorySegmentZeroUnsafe`).
>> 
>> [setMemoryBM.txt](https://github.com/openjdk/jdk/files/14808974/setMemoryBM.txt)
>
> Scott Gibbons has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix UnsafeCopyMemoryMark scope issue

Before I do testing, please sync with mainline.

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

PR Comment: https://git.openjdk.org/jdk/pull/18555#issuecomment-2067777569