[jdk11u-dev] RFR: 8271567: AArch64: AES Galois CounterMode (GCM) interleaved implementation using vector instructions [v2]

[Aleksey Shipilev]

On Fri, 24 Sep 2021 12:59:23 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> This is a backport of the big AES/GCM patch from JDK head. It's a
>> major change and it's had very little time (almost a day) to mature in
>> head, so perhaps it shouldn't be backported to 11 for some time; I
>> wouldn't be at all surprised if some reviewers' reaction was "What
>> have you been smoking?" However, there is a good reason for a
>> backport: OpenJDK on x86 has a major advantage. AES/GCM is an
>> important cipher, the current AArch64 implementation is much slower
>> than x86, and some workloads are severely impacted.
>> 
>> I'm open to all arguments about why this should or shouldn't be pushed,
>> and I'm quite happy to wait for another release cycle or two if people
>> think that's the best course of action.
>
> Andrew Haley has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Whitespace

Since this is math-heavy crypto code, I would rather wait for somebody to use/real-test the upstream implementation first. Unfortunately, timing is against us for JDK 18, as it would release only in March, and so if we want JDK 18 to be proven to work first, this would mean slipping the 11u backport to July 2022.

So I would propose this: wait another 6..8 weeks to see if AArch64 regressions are reported in mainline, then backport this to 11u for January 2022, disabled by default. Have a 11u-specific issue to remember enabling it by default after JDK 18 graduates and people get exposed to this code by default in JDK 18. This way we could also see some opt-in 11u testing (which is presumably a larger population than JDK 18 adopters).

It would also help if we were able to throw some targeted testing for mainline code. Are there known good crypto test suites that could poke the holes in this implementation?

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PR: https://git.openjdk.java.net/jdk11u-dev/pull/410