From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756784AbcLNU6d (ORCPT ); Wed, 14 Dec 2016 15:58:33 -0500 Received: from frisell.zx2c4.com ([192.95.5.64]:49529 "EHLO frisell.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752851AbcLNU63 (ORCPT ); Wed, 14 Dec 2016 15:58:29 -0500 MIME-Version: 1.0 In-Reply-To: References: <20161214035927.30004-1-Jason@zx2c4.com> <20161214184605.24006-1-Jason@zx2c4.com> From: "Jason A. Donenfeld" Date: Wed, 14 Dec 2016 21:55:51 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3 1/3] siphash: add cryptographically secure hashtable function To: Tom Herbert Cc: Netdev , kernel-hardening@lists.openwall.com, LKML , Linux Crypto Mailing List , Jean-Philippe Aumasson , "Daniel J . Bernstein" , Linus Torvalds , Eric Biggers , David Laight Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey Tom, Just following up on what I mentioned in my last email... On Wed, Dec 14, 2016 at 8:35 PM, Jason A. Donenfeld wrote: > I think your suggestion for (2) will contribute to further > optimizations for (1). In v2, I had another patch in there adding > siphash_1word, siphash_2words, etc, like jhash, but I implemented it > by taking u32 variables and then just concatenating these into a > buffer and passing them to the main siphash function. I removed it > from v3 because I thought that these kind of missed the whole point. > In particular: > > a) siphash24_1word, siphash24_2words, siphash24_3words, etc should > take u64, not u32, since that's what siphash operates on natively I implemented these here: https://git.zx2c4.com/linux-dev/commit/?h=siphash&id=4652b6f3643bdba217e2194d89661348bbac48a0 This will be part of the next version of the series I submit. It's not immediately clear that using it is strictly faster than the struct trick though. However, I'm not yet sure why this would be. Jason