RFR: 8266951: Partial in-lining for vectorized mismatch operation using AVX512 masked instructions

[Jatin Bhateja]

On Fri, 14 May 2021 15:26:47 GMT, Paul Sandoz <psandoz at openjdk.org> wrote:

>> Hi @PaulSandoz , I have reinstated the tail handling in java to avoid any impact on other targets. Update performance numbers still show gains for small comparison sized upto -XX:UsePartialInlineSize. Thus patch now does not changes existing java implementation of VectorizedMismatch.
>
> @jatin-bhateja that's good. Did performance numbers change after reverting the Java changes? 
> 
> Do you think it is worth experimenting by setting the threshold to zero when partial inlining is supported? Maybe partial inlining will help for, say, mismatching on arrays with a length of 7 or less bytes e.g. we could test quickly with mismatching for `byte`.

Hi @PaulSandoz , after removal of java side changes, I still see good gains for small sizes but there is considerable penalty.
Will set the threshold to 0, and re-compute the numbers, seek your inputs on adding target specific THRESHOLD. Could not locate any direct public java API or internal jdk API which could be used to fetch target information.

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PR: https://git.openjdk.java.net/jdk/pull/3999