Re: [PATCH v2 04/20] crypto: arm/chacha - expose ARM ChaCha routine as library function

On Fri, Oct 04, 2019 at 04:29:57PM +0200, Jason A. Donenfeld wrote:

On Fri, Oct 4, 2019 at 4:23 PM Ard Biesheuvel [off-list ref] wrote:

quoted

How is it relevant whether the boot CPU is A5 or A7? These are bL
little cores that only implement NEON for feature parity with their bl
big counterparts, but CPU intensive tasks are scheduled on big cores,
where NEON performance is much better than scalar.

Yea big-little might confuse things indeed. Though the performance
difference between the NEON code and the scalar code is not that huge,
and I suspect that big-little machines might benefit from
unconditionally using the scalar code, given that sometimes they might
wind up doing things on the little cores.

Eric - what did you guys wind up doing on Android with the fast scalar
implementation?

We're still just using the NEON implementation from the upstream kernel instead.

- Eric