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Date:   Fri, 5 Oct 2018 20:40:03 +0200
From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
To:     ard.biesheuvel@linaro.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, linux-crypto@vger.kernel.org,
        davem@davemloft.net, gregkh@linuxfoundation.org, sneves@dei.uc.pt,
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        linux@armlinux.org.uk, linux-arm-kernel@lists.infradead.org,
        peter@cryptojedi.org, djb@cr.yp.to
Subject: Re: [PATCH net-next v6 19/23] zinc: Curve25519 ARM implementation
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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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