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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 3A948C07E9A for ; Wed, 14 Jul 2021 05:39:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0BBEC613B0 for ; Wed, 14 Jul 2021 05:39:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237911AbhGNFl4 (ORCPT ); Wed, 14 Jul 2021 01:41:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237903AbhGNFlz (ORCPT ); Wed, 14 Jul 2021 01:41:55 -0400 Received: from mail.as201155.net (mail.as201155.net [IPv6:2a05:a1c0:f001::3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE2D4C0613DD for ; Tue, 13 Jul 2021 22:39:04 -0700 (PDT) Received: from smtps.newmedia-net.de ([2a05:a1c0:0:de::167]:33180 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 1m3XbU-0006Lw-1n; Wed, 14 Jul 2021 07:38:40 +0200 X-CTCH-RefID: str=0001.0A782F1A.60EE7860.0036,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:From:References:To:Subject:MIME-Version:Date:Message-ID; bh=hg3oPq25LK7mumyAQR3rHjMbizy2SNDDhrpngLZvRt8=; b=rzy0fFtw7CCfrcl3lCdsXKmxa1ldDa+Nw/lpx9eZ2kF+XcBgl8L9szPNDjsTW0Wky1Q+SalSW6OGfROvOOjccWoQgvJuOBLZW5PtI2rZmfaAlnlUZhtDIG9TukHlDjReR3HF5bNhXUyDpDCRAAORw6MZlaVNmxeC30kEUCbYvl8=; Message-ID: <8a147d51-9dc0-5767-5d17-793845b9c5f7@dd-wrt.com> Date: Wed, 14 Jul 2021 07:38:39 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:90.0) Gecko/20100101 Thunderbird/90.0 Subject: Re: [Bugreport] ath9k dynack not working/low performance on 5 & 10MHz Bandwidth To: Koen Vandeputte , Petrosilius , linux-wireless@vger.kernel.org References: <2ffcf571-7068-c06f-3879-d02eacdc4895@posteo.de> <8a3718e1-e988-c24a-d94f-34ba0f5349f4@citymesh.com> <339f7aa7-b7ee-b7a8-2e87-a96634c00a32@posteo.de> From: Sebastian Gottschall In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ACL-Warn: RATELIMIT reached, please don't send to many emails per minute X-Received: from [81.201.155.134] (helo=[172.29.0.186]) by webmail.newmedia-net.de with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.72) (envelope-from ) id 1m3XbU-0007CW-93; Wed, 14 Jul 2021 07:38:40 +0200 Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org > > > Above log is with an iperf session running in the background. :-s > > Will look further into this .. > > Regards, > > Koen some cents from me. the chipset has a hw delay/latency which doubles and quadroubles depending on the channel width. this special offset needs to be considered for ack timing calculation. especially at very short distances you will run into a problem that if this calculation is wrong, the ack timing register contains a lower value than the hw delay/latency. this will result in a effective negative ack value. maybe its worth to check if the values used for this latency offset are correct? i found also a patch in my own code which i made many years ago (i cannot remember why) but maybe it helps @@ -1128,11 +1110,10 @@                 slottime = ah->slottime;         } +         /* As defined by IEEE 802.11-2007 17.3.8.6 */         slottime += 3 * ah->coverage_class;         acktimeout = slottime + sifstime + ack_offset; +       eifs += (6 * ah->coverage_class);         ctstimeout = acktimeout;         /* Sebastian > >