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

[Paul Sandoz]

On Fri, 14 May 2021 18:55:44 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> @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.

@jatin-bhateja glad the variation is small. 
If the subsequent results without and with a zero threshold for lengths below the current threshold show increased benefits i am sure we can find a way to surface up some detail.

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