From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x230.google.com (mail-wm0-x230.google.com [IPv6:2a00:1450:400c:c09::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id DF4E53BA8E for ; Tue, 12 Jun 2018 03:46:43 -0400 (EDT) Received: by mail-wm0-x230.google.com with SMTP id l15-v6so13862518wmc.1 for ; Tue, 12 Jun 2018 00:46:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=heistp.net; s=google; h=from:content-transfer-encoding:subject:message-id:date:to :mime-version; bh=IS0cSYbSasZcCyhTSMKNfs4y5LDJMaF3dI39qm6lDKk=; b=i9dWqxJzgijVdyZWAHBn7Tv0zFTZiwE1nr6BY4ZY+5MVLKeodk2afl5O3cyFWYcM2C P5KQwgsMtOGmNy49Xvz3x1eCsDHkfsTFvOVLvF2r8vcxDeiFnGRvN4+TNUmdLl9gM+gb Xi4/bTurSnByxr5EjzhnyFAKtVb0TsH69r5qFKWiLbG1DapAtEHx+wbGgR3szXZNBbNi QEZCXGCwtbe27pd6IE+ERMKUdCRLWOUHvljOisxPytz1bh8o/vdPKNVDuZ/v9eh8eL96 Pc668H+iPK5MLua3CXM8rEQuQhWg1JNK8CoLHBH8hn76zs5bZQoGLwx8j6J/vxLsceVl g7mg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:content-transfer-encoding:subject :message-id:date:to:mime-version; bh=IS0cSYbSasZcCyhTSMKNfs4y5LDJMaF3dI39qm6lDKk=; b=pO/twIVMPcXw7Htw+05Gy7Xu2+n5Kh8uiy8CwvDW9SqWGe/sa4qbm3ml52g0dexAUn QLnoo34IMizPSeQKz/AFDL5Yel6jh0UWMO01oBfHOTWxL19ocMpnXlLbdMFt2IWwDXTf XdeSlWDxfcZL3Nieyq3aQhQbtMSFhhEnqF/u22/6b/zc9WVs9AJVHcOM3HLcNfu3oAVb L/Salhrj/13utnUKoSVxGzZHURR10zcIzd3gHfca9hgiY6AdAJ7EC9ENF7a4dElaV1W0 lHMfuh6TFmy90idE6muFeDqy8o7f/P2tw2KFixyn083sZHRIwB4lBW8+9Lb2i8eeZNal 0LLQ== X-Gm-Message-State: APt69E16mfSCGwHLpvyWvws1GQHTIT9vjSvEkm6u9XX4qlanRjxN2WuP YndRAzL/FDtnIkANb1sUo4ofvAmSAYE= X-Google-Smtp-Source: ADUXVKLQLW/mCJE9HnerjSltSgXItrsUpdFgiesq9GgeBDvve0uC67qkKylC/eSVZAV97/9OSCZnUA== X-Received: by 2002:a1c:40d4:: with SMTP id n203-v6mr1280988wma.101.1528789602839; Tue, 12 Jun 2018 00:46:42 -0700 (PDT) Received: from tron.luk.heistp.net (h-1169.lbcfree.net. [185.193.85.130]) by smtp.gmail.com with ESMTPSA id r123-v6sm595947wmb.21.2018.06.12.00.46.42 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 12 Jun 2018 00:46:42 -0700 (PDT) From: Pete Heist Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Message-Id: <111C85D5-859A-4F2E-8D6E-DA32A4BD5AA8@heistp.net> Date: Tue, 12 Jun 2018 09:46:41 +0200 To: make-wifi-fast@lists.bufferbloat.net Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) X-Mailer: Apple Mail (2.3124) Subject: [Make-wifi-fast] NanoStation M5 anyone? X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Jun 2018 07:46:44 -0000 This is an appeal to anyone who has access to a NanoStation M5 and a = little time to try to reproduce this problem and add to this post: = https://community.ubnt.com/t5/airMAX-Installation/NanoStation-M5-ping-spik= es-about-once-per-second-even-just-to/td-p/2358704 I=E2=80=99ve been trying unsuccessfully to demonstrate to Ubiquiti that = they have a bug somewhere that causes isochronous latency spikes. It = seems what=E2=80=99s happening is that for a fixed period of time (20ms = when one Ethernet port is in use and 40ms when two are in use), once per = second, the device queues packets until the pause is over. The function = ar7240sw_phy_poll_reset in ag71xx_ar7240.c exactly describes the = behavior of 20ms delays when one port is connected and 40ms delays when = two ports are connected, so basically it appears that the Ethernet / = internal switch device is being reset once per second for some reason. So far nobody has seemed to care (after all, who=E2=80=99s counting 40ms = here or there when it comes to WiFi?), but it does pollute my test = results and may be causing latency spikes wherever these devices are = deployed (like, worldwide). So if anyone else tests this and can add = some weight to the discussion, I=E2=80=99d be glad. :) Pete