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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: David Laight <David.Laight@aculab.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Theodore Tso <tytso@mit.edu>,
	Greg KH <gregkh@linuxfoundation.org>,
	Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
Subject: Re: [PATCH v2 2/2] random: use BLAKE2s instead of SHA1 in extraction
Date: Tue, 11 Jan 2022 19:26:03 +0100	[thread overview]
Message-ID: <CAHmME9rvRZVgy+1wr94dC8pCV-qgLSm9mk7FkqbtjM0xz=HT1w@mail.gmail.com> (raw)
In-Reply-To: <caed82818cdb466aade033501f57d183@AcuMS.aculab.com>

On Tue, Jan 11, 2022 at 4:47 PM David Laight <David.Laight@aculab.com> wrote:
> > -     int i;
> > +     int i, j;
>
> Use unsigned int i, j;
> Ensures the '% 4' are done as '& 3' and the divides as shifts.
> Unless the compiler manages to track the valid values that will
> even generate better code on x86-64.
> (Saves a sign extension prior to the array indexes.)

Ack.

> I think I'd look at doing [0..3] then [4..7] to save execution time.

I actually wound up making the same change to sha1 instead of blake2s
for v2 of this, and achieved pretty similar results, but I think
that's more satisfactory of a conclusion. v2 is here:
https://lore.kernel.org/linux-crypto/20220111181037.632969-1-Jason@zx2c4.com/T/#u

Jason

  reply	other threads:[~2022-01-11 18:26 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-23 14:11 [PATCH v2 1/2] lib/crypto: blake2s: include as built-in Jason A. Donenfeld
2021-12-23 14:11 ` [PATCH v2 2/2] random: use BLAKE2s instead of SHA1 in extraction Jason A. Donenfeld
2021-12-24 20:56   ` Eric Biggers
2022-01-05 21:42     ` Eric Biggers
2021-12-27 15:52   ` Theodore Ts'o
2022-01-11 11:38   ` Geert Uytterhoeven
2022-01-11 12:28     ` Jason A. Donenfeld
2022-01-11 12:50       ` Jason A. Donenfeld
2022-01-11 12:57         ` Geert Uytterhoeven
2022-01-11 13:00           ` Jason A. Donenfeld
2022-01-11 15:46         ` David Laight
2022-01-11 18:26           ` Jason A. Donenfeld [this message]
2022-01-14 17:27         ` David Laight
2022-01-14 17:31           ` Jason A. Donenfeld
2022-01-11 12:51       ` Geert Uytterhoeven
2022-01-11 13:02         ` Jason A. Donenfeld
2022-01-11 13:49           ` [PATCH crypto 0/2] smaller blake2s code size on m68k and other small platforms Jason A. Donenfeld
2022-01-11 13:49             ` [PATCH crypto 1/2] lib/crypto: blake2s-generic: reduce code size on small systems Jason A. Donenfeld
2022-01-12 10:57               ` Geert Uytterhoeven
2022-01-12 13:16                 ` Jason A. Donenfeld
2022-01-12 18:31               ` Eric Biggers
2022-01-12 18:50                 ` Jason A. Donenfeld
2022-01-12 21:27                   ` David Laight
2022-01-12 22:00                     ` Jason A. Donenfeld
2022-01-11 13:49             ` [PATCH crypto 2/2] lib/crypto: blake2s: move hmac construction into wireguard Jason A. Donenfeld
2022-01-11 14:43               ` Ard Biesheuvel
2022-01-12 18:35               ` Eric Biggers
2022-01-11 18:10             ` [PATCH crypto v2 0/2] reduce code size from blake2s on m68k and other small platforms Jason A. Donenfeld
2022-01-11 18:10               ` [PATCH crypto v2 1/2] lib/crypto: blake2s: move hmac construction into wireguard Jason A. Donenfeld
2022-01-11 18:10               ` [PATCH crypto v2 2/2] lib/crypto: sha1: re-roll loops to reduce code size Jason A. Donenfeld
2022-01-11 22:05               ` [PATCH crypto v3 0/2] reduce code size from blake2s on m68k and other small platforms Jason A. Donenfeld
2022-01-11 22:05                 ` [PATCH crypto v3 1/2] lib/crypto: blake2s: move hmac construction into wireguard Jason A. Donenfeld
2022-01-11 22:05                 ` [PATCH crypto v3 2/2] lib/crypto: sha1: re-roll loops to reduce code size Jason A. Donenfeld
2022-01-12 10:59                 ` [PATCH crypto v3 0/2] reduce code size from blake2s on m68k and other small platforms Geert Uytterhoeven
2022-01-12 13:18                   ` Jason A. Donenfeld
2022-01-18  6:42                     ` Herbert Xu
2022-01-18 11:43                       ` Jason A. Donenfeld
2022-01-18 12:44                         ` David Laight
2022-01-18 12:50                           ` Jason A. Donenfeld
2021-12-23 14:20 ` [PATCH v2 1/2] lib/crypto: blake2s: include as built-in Ard Biesheuvel
2021-12-24 13:35 ` Greg KH
2021-12-25  9:26 ` Masahiro Yamada
2021-12-25 10:26   ` Ard Biesheuvel
2021-12-25 15:47     ` Masahiro Yamada
2021-12-27 13:43       ` Jason A. Donenfeld
2021-12-27 13:47         ` [PATCH v3] " Jason A. Donenfeld
2021-12-27 14:20           ` [PATCH v4] " Jason A. Donenfeld
2022-01-01 15:59             ` [PATCH v5] " Jason A. Donenfeld
2022-01-02 20:42               ` [PATCH v6] " Jason A. Donenfeld
2022-01-03  3:23                 ` Herbert Xu
2022-01-03  3:45                   ` Jason A. Donenfeld
2022-01-03  4:06                     ` Herbert Xu
2022-01-03 11:57                       ` Jason A. Donenfeld
2022-01-03 12:31                         ` [PATCH v7] " Jason A. Donenfeld
2022-01-04  1:21                           ` Herbert Xu
2022-01-04 17:02                             ` Ard Biesheuvel
2022-01-04 17:04                               ` Jason A. Donenfeld
2022-01-05  0:28                               ` Herbert Xu
2022-01-05 21:53                               ` Eric Biggers
2022-01-05 22:01                                 ` Ard Biesheuvel
2022-01-05 22:09                                   ` Eric Biggers

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