RFR: 8344144: AES/CBC slow at big payloads [v2]

[Volodymyr Paprotski]

On Fri, 15 Nov 2024 12:52:28 GMT, Artur Barashev <abarashev at openjdk.org> wrote:

>> I don't think it matters either way performance-wise, or from any other point of view in this case, but as a rule of thumb, I think for readability/maintainability it is worth to give up a bit of code size (especially if that is only source code size, since the compiler would duplicate the runtime code anyways) and/or performance. Of course, it is hard to decide which version is more readable/maintainable. For me, in this case, the source code duplication seems to be the better solution, I would not write a helper function for a 3-line for loop. I have spent many hours of my life trying to figure out whether I brake something if I make a little change in a function that appears on multiple code paths...
>
> I see, I agree it will add to the learning curve for somebody new looking at the code. Keeping things the way they are has its merits. It won't be 3 lines though, we would replace all those 9 lines with 1 line:
> `return chunkOperation(cipher, cipherOffset, cipherLen, plain, plainOffset, false);`

I would prefer to leave it as is; two reasons.. I do think its more readable 'not to have to track down the one-liner function'. I admit this is a matter of taste, so 'can be convinced otherwise'. 

But the second reason, I don't know that we should rely on the JIT necessarily inlining things.. (Anecdotally.. I 'cleaned up' `(Montgomery)IntegerPolynomialP256.mult` with a `for(i = 0:4)` loop that can clearly be unrolled but makes for much more readable code. Never was unrolled)

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PR Review Comment: https://git.openjdk.org/jdk/pull/22086#discussion_r1844308172