RFR: 8296507: GCM using more memory than necessary with in-place operations

[Anthony Scarpino]

On Wed, 16 Nov 2022 18:48:58 GMT, Anthony Scarpino <ascarpino at openjdk.org> wrote:

> Thanks for looking into this, @ascarpino!
> 
> In testing this using a local build, it improves performance in cases using heap buffers (a super-set of the socket case), however servers which use direct byte-buffers still exhibit a similar performance regression (heavy allocation compared to jdk17, ~10% slower TLS performance in HTTP+TLS benchmarks). It's possible that has a different root cause, but the outcome is strikingly similar.

Looking at this, it's not related to the same in-place issues.  This is a result of the combined intrinsics requirement .  Maybe some better tuning can be done, but I think this is unavoidable.  I can consider this in a future PR

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PR: https://git.openjdk.org/jdk/pull/11121