MIME-Version: 1.0
References: <CAHmME9qbnYmhvsuarButi6s=58=FPiti0Z-QnGMJ=OsMzy1eOg@mail.gmail.com>
 <20220111134934.324663-1-Jason@zx2c4.com> <20220111134934.324663-2-Jason@zx2c4.com>
 <Yd8enQTocuCSQVkT@gmail.com>
In-Reply-To: <Yd8enQTocuCSQVkT@gmail.com>
From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
Date:   Wed, 12 Jan 2022 19:50:58 +0100
Message-ID: <CAHmME9qGs8yfYy0GVcV8XaUt9cjCqQF2D79RvrsQE+CNLCeojA@mail.gmail.com>
Subject: Re: [PATCH crypto 1/2] lib/crypto: blake2s-generic: reduce code size
 on small systems
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Netdev <netdev@vger.kernel.org>,
        WireGuard mailing list <wireguard@lists.zx2c4.com>,
        LKML <linux-kernel@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        "Theodore Ts'o" <tytso@mit.edu>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Wed, Jan 12, 2022 at 7:32 PM Eric Biggers <ebiggers@kernel.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/