linux-kernel - Re: [PATCH crypto 1/2] lib/crypto: blake2s-generic: reduce code size on small systems

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Date:   Wed, 12 Jan 2022 19:50:58 +0100
From:   "Jason A. Donenfeld" <Jason@...c4.com>
To:     Eric Biggers <ebiggers@...nel.org>
Cc:     Linux Crypto Mailing List <linux-crypto@...r.kernel.org>,
        Netdev <netdev@...r.kernel.org>,
        WireGuard mailing list <wireguard@...ts.zx2c4.com>,
        LKML <linux-kernel@...r.kernel.org>, bpf <bpf@...r.kernel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        "Theodore Ts'o" <tytso@....edu>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jean-Philippe Aumasson <jeanphilippe.aumasson@...il.com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Herbert Xu <herbert@...dor.apana.org.au>
Subject: Re: [PATCH crypto 1/2] lib/crypto: blake2s-generic: reduce code size
 on small systems

On Wed, Jan 12, 2022 at 7:32 PM Eric Biggers <ebiggers@...nel.org> wrote:
> How about unrolling the inner loop but not the outer one?  Wouldn't that give
> most of the benefit, without hurting performance as much?
>
> If you stay with this approach and don't unroll either loop, can you use 'r' and
> 'i' instead of 'i' and 'j', to match the naming in G()?

All this might work, sure. But as mentioned earlier, I've abandoned
this entirely, as I don't think this patch is necessary. See the v3
patchset instead:

https://lore.kernel.org/linux-crypto/20220111220506.742067-1-Jason@zx2c4.com/