Re: [PATCH net-next v6 19/23] zinc: Curve25519 ARM implementation

From: Jason A. Donenfeld
Date: Fri Oct 05 2018 - 14:40:10 EST


Hey Dan,

On Fri, Oct 05, 2018 at 03:05:38PM -0000, D. J. Bernstein wrote:
> Of course, there are other ARM microarchitectures, and there are many
> cases where different microarchitectures prefer different optimizations.
> The kernel already has boot-time benchmarks for different optimizations
> for raid6, and should do the same for crypto code, so that implementors
> can focus on each microarchitecture separately rather than living in the
> barbaric world of having to choose which CPUs to favor.

I've been playing a bit with some code to do this sort of thing,
choosing a set of implementations to enable or disable by trying all the
combinations, and then calculating a quick median. I don't know if I'll
submit that for the initial merge of this patchset -- and in fact all
the current implementations I'm proposing are pretty much okay on
microarchitectures -- but down the line this could be useful as a
mechanism.

Jason

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