linux-kernel - Re: [PATCH crypto v3 0/2] reduce code size from blake2s on m68k and other small platforms

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Message-ID: <CAHmME9qqqz80hd4er8eAqYpo1gzLSPVyDub0sfmY0YBEqLeiHw@mail.gmail.com>
Date:   Tue, 18 Jan 2022 13:50:51 +0100
From:   "Jason A. Donenfeld" <Jason@...c4.com>
To:     David Laight <David.Laight@...lab.com>
Cc:     Herbert Xu <herbert@...dor.apana.org.au>,
        "geert@...ux-m68k.org" <geert@...ux-m68k.org>,
        "linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "wireguard@...ts.zx2c4.com" <wireguard@...ts.zx2c4.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "bpf@...r.kernel.org" <bpf@...r.kernel.org>,
        "tytso@....edu" <tytso@....edu>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "jeanphilippe.aumasson@...il.com" <jeanphilippe.aumasson@...il.com>,
        "ardb@...nel.org" <ardb@...nel.org>
Subject: Re: [PATCH crypto v3 0/2] reduce code size from blake2s on m68k and
 other small platforms

On Tue, Jan 18, 2022 at 1:45 PM David Laight <David.Laight@...lab.com> wrote:
> I've rammed the code through godbolt... https://godbolt.org/z/Wv64z9zG8
>
> Some things I've noticed;

It seems like you've done a lot of work here but...

>    But I've not got time to test the code.

But you're not going to take it all the way. So it unfortunately
amounts to mailing list armchair optimization. That's too bad because
it really seems like you might be onto something worth seeing through.
As I've mentioned a few times now, I've dropped the blake2s
optimization patch, and I won't be developing that further. But it
appears as though you've really been captured by it, so I urge you:
please send a real patch with benchmarks on various platforms! (And CC
me on the patch.) Faster reference code would really be terrific.

Jason