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=unavailable 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 078C7C4360F for ; Wed, 3 Apr 2019 16:12:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C0272206B7 for ; Wed, 3 Apr 2019 16:12:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726721AbfDCQMH (ORCPT ); Wed, 3 Apr 2019 12:12:07 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:44100 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726099AbfDCQMG (ORCPT ); Wed, 3 Apr 2019 12:12:06 -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 48EBC80D; Wed, 3 Apr 2019 09:12:06 -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 77B1E3F68F; Wed, 3 Apr 2019 09:12:04 -0700 (PDT) Subject: Re: [PATCH 1/2] stmmac: introduce flag to dynamically disable TX offload for rockchip devices To: "Leonidas P. Papadakos" , Jose Abreu Cc: Philipp Tomsich , =?UTF-8?Q?Heiko_St=c3=bcbner?= , =?UTF-8?Q?Christoph_M=c3=bcllner?= , Maxime Coquelin , Alexandre Torgue , netdev@vger.kernel.org, LKML , Linux ARM , Klaus Goger References: <20190401181840.31255-1-papadakospan@gmail.com> <9d65a22a-2288-dc53-0059-ec4a31424dd8@arm.com> <2312344.mOsv7YkeBG@diego> <9EC67532-2D43-4AAD-BFA7-8B6797067427@theobroma-systems.com> <78EB27739596EE489E55E81C33FEC33A0B421348@de02wembxa.internal.synopsys.com> <4a9839d6-3d90-4354-7b64-78d5c1126e99@arm.com> <78EB27739596EE489E55E81C33FEC33A0B423811@de02wembxa.internal.synopsys.com> <1554245296.1271.0@gmail.com> <78EB27739596EE489E55E81C33FEC33A0B4254A0@de02wembxa.internal.synopsys.com> <1554305721.1328.0@gmail.com> <1554306954.1328.1@gmail.com> From: Robin Murphy Message-ID: Date: Wed, 3 Apr 2019 17:12:03 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <1554306954.1328.1@gmail.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 03/04/2019 16:55, Leonidas P. Papadakos wrote: > >> If snps,no-pbl-x8 does indeed have a performace hit, should the >> workaround be to >> a) turn tx checksumming off or >> b) snps,no-pbl-x8 set? >> >> I'll test to see the difference > > Update: It really seems like snps,no-pbl-x8 is the better option. > So I say, replace snps,force_thresh_dma_mode with it. Yes, I would expect software checksumming to have a much more noticeable impact (in fact I've already been trying to get round to benchmarking some arm64 checksum optimisations on my RK3328 precisely because of this issue). If I'm interpreting the register descriptions in the Rockchip TRMs correctly, it seems like no-pbl-x8 is a relatively big hammer and there should still be room to tune things a bit closer to the maximum limits - I'll have another play this evening to see if I've understood things right. Robin.