From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 175F2C00449 for ; Fri, 5 Oct 2018 18:40:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BED4C21473 for ; Fri, 5 Oct 2018 18:40:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="ZGjzMudV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BED4C21473 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=zx2c4.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728947AbeJFBkE (ORCPT ); Fri, 5 Oct 2018 21:40:04 -0400 Received: from frisell.zx2c4.com ([192.95.5.64]:59661 "EHLO frisell.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728139AbeJFBkE (ORCPT ); Fri, 5 Oct 2018 21:40:04 -0400 Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTP id d7db8103; Fri, 5 Oct 2018 18:39:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=date:from:to :subject:message-id:references:mime-version:content-type :in-reply-to; s=mail; bh=0KK8ySgqtXWyvI77mHHL3ERXrcc=; b=ZGjzMud Vv4oGKEzO3oQm9zMYhT3EsK0cDFbNzgm7/BJRGPnw0YgZZSZxVHSRRZtQsRurzxG rlj0+VO/yGDsGXmkdvnD2q2LZQW065l89X3fwXFXzyFL/kdWkJ/bm5w05Vim0rkg f0U3R7XVTaUpxAKWWUF767eTkW+Se3WYFCWBVtwfloSfWtHYo8Dwip/BXI/sIPYe R3m5bRMF+GQ6hiYLm4Ckjs+xOAM5dviXnl5zjlwxS/eAFizLi9xxIAbX+vAZ074B trxnnCcLtM2M+PAAh6PPnkdn9vkxfE4hCeZSuAGfTlIujl+DGZQ6sJfvZx9J+sRN YPEAhIgt3P4mA8w== Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 4e134b1f (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256:NO); Fri, 5 Oct 2018 18:39:39 +0000 (UTC) Date: Fri, 5 Oct 2018 20:40:03 +0200 From: "Jason A. Donenfeld" To: ard.biesheuvel@linaro.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-crypto@vger.kernel.org, davem@davemloft.net, gregkh@linuxfoundation.org, sneves@dei.uc.pt, luto@kernel.org, jeanphilippe.aumasson@gmail.com, linux@armlinux.org.uk, linux-arm-kernel@lists.infradead.org, peter@cryptojedi.org, djb@cr.yp.to Subject: Re: [PATCH net-next v6 19/23] zinc: Curve25519 ARM implementation Message-ID: <20181005184001.GA10106@zx2c4.com> References: <20180925145622.29959-1-Jason@zx2c4.com> <20180925145622.29959-20-Jason@zx2c4.com> <20181005150538.17006.qmail@cr.yp.to> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="C7zPtVaVf+AK4Oqc" Content-Disposition: inline In-Reply-To: <20181005150538.17006.qmail@cr.yp.to> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --C7zPtVaVf+AK4Oqc Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Hey Dan, On Fri, Oct 05, 2018 at 03:05:38PM -0000, D. J. Bernstein wrote: > Of course, there are other ARM microarchitectures, and there are many > cases where different microarchitectures prefer different optimizations. > The kernel already has boot-time benchmarks for different optimizations > for raid6, and should do the same for crypto code, so that implementors > can focus on each microarchitecture separately rather than living in the > barbaric world of having to choose which CPUs to favor. I've been playing a bit with some code to do this sort of thing, choosing a set of implementations to enable or disable by trying all the combinations, and then calculating a quick median. I don't know if I'll submit that for the initial merge of this patchset -- and in fact all the current implementations I'm proposing are pretty much okay on microarchitectures -- but down the line this could be useful as a mechanism. 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