From: Eric Biggers <ebiggers@kernel.org>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
sneves@dei.uc.pt
Subject: Re: [PATCH] random: use rejection sampling for uniform bounded random integers
Date: Mon, 17 Oct 2022 11:27:17 -0700 [thread overview]
Message-ID: <Y02ehdiCtHyLErB8@sol.localdomain> (raw)
In-Reply-To: <20221017023752.3907-1-Jason@zx2c4.com>
On Sun, Oct 16, 2022 at 08:37:53PM -0600, Jason A. Donenfeld wrote:
> In order to be efficient, we implement a kernel-specific variant of
> Daniel Lemire's algorithm from "Fast Random Integer Generation in an
> Interval", linked below. The kernel's variant takes advantage of
> constant folding to avoid divisions entirely in the vast majority of
> cases, works on both 32-bit and 64-bit architectures, and requests a
> minimal amount of bytes from the RNG.
>
> Link: https://arxiv.org/pdf/1805.10941.pdf
Thanks for doing this! Your code looks correct, but it was hard for me to
understand until I read the paper that is linked to. Could you include a brief
comment in the code that explains the algorithm? Also, though the code looks
correct, I assume that you've also explicitly tested that each of the four code
paths produce uniform random numbers as intended?
- Eric
next prev parent reply other threads:[~2022-10-17 18:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-17 2:37 [PATCH] random: use rejection sampling for uniform bounded random integers Jason A. Donenfeld
2022-10-17 18:27 ` Eric Biggers [this message]
2022-10-18 5:31 ` Jason A. Donenfeld
2022-10-18 7:04 ` Eric Biggers
2022-10-18 17:34 ` [PATCH v2] " Jason A. Donenfeld
2022-10-17 20:39 ` [PATCH] " Yann Droneaud
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