Integrated: 8329331: Intrinsify Unsafe::setMemory

[Scott Gibbons]

On Fri, 29 Mar 2024 22:32:06 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)

This pull request has now been integrated.

Changeset: bd67ac69
Author:    Scott Gibbons <sgibbons at openjdk.org>
Committer: Jatin Bhateja <jbhateja at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/bd67ac69a234cd1096e534c7d4a45d88715884b4
Stats:     507 lines in 36 files changed: 420 ins; 5 del; 82 mod

8329331: Intrinsify Unsafe::setMemory

Reviewed-by: sviswanathan, jbhateja, kvn

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PR: https://git.openjdk.org/jdk/pull/18555