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=-6.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 172E6C433DF for ; Thu, 30 Jul 2020 17:19:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF28E2082E for ; Thu, 30 Jul 2020 17:19:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=dd-wrt.com header.i=@dd-wrt.com header.b="KRlvxZ+9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728437AbgG3RTY (ORCPT ); Thu, 30 Jul 2020 13:19:24 -0400 Received: from mail.as201155.net ([185.84.6.188]:29779 "EHLO mail.as201155.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727072AbgG3RTX (ORCPT ); Thu, 30 Jul 2020 13:19:23 -0400 Received: from smtps.newmedia-net.de ([2a05:a1c0:0:de::167]:54500 helo=webmail.newmedia-net.de) by mail.as201155.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1k1CD9-0005kR-1c; Thu, 30 Jul 2020 19:19:19 +0200 X-CTCH-RefID: str=0001.0A782F1D.5F230117.0050,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=dd-wrt.com; s=mikd; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject; bh=47FfpEUngNOrDbK0FxoTLivet0N62PUjorlzAZ+Y5uo=; b=KRlvxZ+9ru/rNaY174fWpXAR8caDVljwb9Xb/RxeXiAlZZEQ4r3jF1cY9iUCaVMtq/MeS72cyrrvXx0eofQDKspDtyIlzNSz7dX2G3e84VcayLYduY7KxVyfuDY7ww0ySjKKraoJ5lJYkNXTtcHN1kZl4pzPcAhq3T6D3Abk3KE=; Subject: Re: [PATCH] net: add support for threaded NAPI polling To: David Laight , Eric Dumazet , Felix Fietkau , "netdev@vger.kernel.org" Cc: Hillf Danton References: <20200729165058.83984-1-nbd@nbd.name> <866c7d83-868d-120e-f535-926c4cc9e615@gmail.com> <5aa0c26f-d3f1-b33f-a598-e4727d6f10f0@dd-wrt.com> <1743bcaa2dfb4b6393b4d228cf079fe3@AcuMS.aculab.com> From: Sebastian Gottschall Message-ID: <0de774d0-7e9e-8a44-0f0c-584a9cb9ee96@dd-wrt.com> Date: Thu, 30 Jul 2020 19:19:17 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:79.0) Gecko/20100101 Thunderbird/79.0 MIME-Version: 1.0 In-Reply-To: <1743bcaa2dfb4b6393b4d228cf079fe3@AcuMS.aculab.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Received: from [2a01:7700:8040:300:315c:d267:8dd:d539] by webmail.newmedia-net.de with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.72) (envelope-from ) id 1k1CD8-00061U-VD; Thu, 30 Jul 2020 19:19:18 +0200 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Am 30.07.2020 um 17:42 schrieb David Laight: > From: Sebastian Gottschall >> Sent: 30 July 2020 15:30 > ... >>> Quite frankly, I do believe this STATE_THREADED status should be a generic NAPI attribute >>> that can be changed dynamically, at admin request, instead of having to change/recompile >>> a driver. >> thats not that easy. wifi devices do use dummy netdev devices. they are >> not visible to sysfs and other administrative options. >> so changing it would just be possible if a special mac80211 based >> control would be implemented for these drivers. >> for standard netdev devices it isnt a big thing to implement a >> administrative control by sysfs (if you are talking about such a feature) > ISTM that a global flag that made all NAPI callbacks be made > from a worker thread rather than softint would be more approriate. > Or even something that made the softint callbacks themselves > only run an a specific high(ish) priority kernel thread. > > While it might slow down setups that need very low ethernet > latency it will help those that don't want application RT threads > to be 'stolen' by the softint code while they hold application > mutex or are waiting to be woken by a cv. this will not work either. i already identified drivers which are incompatible with that approach. (marvell mvneta for instance) so threading should be a feature which should be enabled or disabled on known working chipsets. but it cannot be used as set and forget feature for everything unless the specific driver are fixed. > > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales)