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=-1.0 required=3.0 tests=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 89EEFC04E53 for ; Wed, 15 May 2019 12:16:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5103620675 for ; Wed, 15 May 2019 12:16:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728428AbfEOMQO (ORCPT ); Wed, 15 May 2019 08:16:14 -0400 Received: from foss.arm.com ([217.140.101.70]:40858 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728001AbfEOLCq (ORCPT ); Wed, 15 May 2019 07:02:46 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 21FA480D; Wed, 15 May 2019 04:02:46 -0700 (PDT) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BD9043F703; Wed, 15 May 2019 04:02:44 -0700 (PDT) Subject: Re: [PATCH] arm64: do_csum: implement accelerated scalar version To: Will Deacon Cc: Zhangshaokun , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org, ilias.apalodimas@linaro.org, "huanglingyan (A)" , steve.capper@arm.com References: <20190218230842.11448-1-ard.biesheuvel@linaro.org> <20190412095243.GA27193@fuggles.cambridge.arm.com> <41b30c72-c1c5-14b2-b2e1-3507d552830d@arm.com> <20190515094704.GC24357@fuggles.cambridge.arm.com> From: Robin Murphy Message-ID: <67c2f851-9a4d-e18d-4664-c07287e72ebf@arm.com> Date: Wed, 15 May 2019 12:02:43 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190515094704.GC24357@fuggles.cambridge.arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 15/05/2019 10:47, Will Deacon wrote: > On Mon, Apr 15, 2019 at 07:18:22PM +0100, Robin Murphy wrote: >> On 12/04/2019 10:52, Will Deacon wrote: >>> I'm waiting for Robin to come back with numbers for a C implementation. >>> >>> Robin -- did you get anywhere with that? >> >> Still not what I would call finished, but where I've got so far (besides an >> increasingly elaborate test rig) is as below - it still wants some unrolling >> in the middle to really fly (and actual testing on BE), but the worst-case >> performance already equals or just beats this asm version on Cortex-A53 with >> GCC 7 (by virtue of being alignment-insensitive and branchless except for >> the loop). Unfortunately, the advantage of C code being instrumentable does >> also come around to bite me... > > Is there any interest from anybody in spinning a proper patch out of this? > Shaokun? FWIW I've learned how to fix the KASAN thing now, so I'll try giving this some more love while I've got other outstanding optimisation stuff to look at anyway. Robin.