RFR: 8317763: Follow-up to AVX512 intrinsics for Arrays.sort() PR

Sandhya Viswanathan sviswanathan at openjdk.org
Wed Oct 11 18:35:04 UTC 2023


On Wed, 11 Oct 2023 09:25:15 GMT, Andrew Haley <aph at openjdk.org> wrote:

> > Forgive me, I might be missing something very obvious, but is there any particular reason to entirely disable the SIMD accelerated sort on Zen 4 rather than having an alternate code path for Zen 4 where it has the `compressstoreu` instructions split up into separate `compress` and `storeu` instructions so that Zen 4 platforms can still benefit from a decent degree of performance uplift from AVX512 acceleration of sort?
> 
> I don't think you're missing anything. This should be done, rather than disabling the intrinsic.

With this PR we want to fix the urgent Alpine Linux build issues and the Zen 4 perf regression. At the minimum, we don't want to hurt performance for Zen 4, hence restricting the intrinsic to only Intel for now as suggested in the [Reddit discussion](https://www.reddit.com/r/java/comments/171t5sj/comment/k3v9ko5/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button).  Improving perf for it could be a separate PR from someone more familiar with Zen 4.

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PR Comment: https://git.openjdk.org/jdk/pull/16124#issuecomment-1758268675


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