From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-x235.google.com (mail-wg0-x235.google.com [IPv6:2a00:1450:400c:c00::235]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 2615821F3E0; Fri, 15 May 2015 04:10:36 -0700 (PDT) Received: by wgin8 with SMTP id n8so109101808wgi.0; Fri, 15 May 2015 04:10:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=DLfFXVK53ki69oB0pyMGMMYaBGAGYfwOOcQTCaInm+4=; b=gZdkUJL8kx1ydoKGcaumvYoaKRWCQ6a3VZ9d8D963seLau4u4qt9DtE40NROsfsKbm 2kpG3RasJEpe82dsYZz/j+C+SCg1tLe/NekN3ZYqz3nCFG032BGHetGCPpGKcaVaQhfD OOZWr3s385pOa1vkN1P0/UQuMdDwDfEO2wdIxOTvGx1XdPjLb4TzzsOcb2XfzAn+mvGR kMg78q/Jftf0xPmARGJYhW9aCIq5DBJvGADdotRdUcoWXMB3BQyJRwXXRYGiGFw5cs2Z iaXTFFTJm1IghtEULu78MFkpNTqcpTKpUp3NrGGllqXUeLZ/T9AjH3paj8fmRNoVDmC1 4LwA== X-Received: by 10.194.59.79 with SMTP id x15mr16748709wjq.81.1431688232669; Fri, 15 May 2015 04:10:32 -0700 (PDT) Received: from volcano.localdomain (host-92-11-216-78.as43234.net. [92.11.216.78]) by mx.google.com with ESMTPSA id y7sm1966507wjw.16.2015.05.15.04.10.31 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 May 2015 04:10:31 -0700 (PDT) Message-ID: <5555D426.7020408@gmail.com> Date: Fri, 15 May 2015 12:10:30 +0100 From: Alan Jenkins User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Sebastian Moeller , "Eggert, Lars" References: <8C015B1B-EFBA-4647-AD83-BAFDD16A4AF2@netapp.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Cc: "cake@lists.bufferbloat.net" , "cerowrt-devel@lists.bufferbloat.net" , bloat Subject: Re: [Cerowrt-devel] [Cake] [Bloat] heisenbug: dslreports 16 flow test vs cablemodems X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 15 May 2015 11:11:06 -0000 On 15/05/15 09:55, Sebastian Moeller wrote: > Hi Lars, > > > On May 15, 2015, at 10:18 , Eggert, Lars wrote: > >> On 2015-5-15, at 06:44, Aaron Wood wrote: >>> ICMP prioritization over TCP? >> Probably. > Interesting so far I often heard ICMP echo requests are bad as they are often rate-limited and/or processed in a slow path in routers... Yes, if you ping an ISP router itself. You can avoid that by pinging an end-host. Then you'll reveal silly QoS implementations at the edge of the network which prioritize ping. Or hit one like SQM (simple.qos) that de-prioritises it. So you can get biased results in either direction :). Need to test very carefully. I like that rrul includes udp probes as well. The betterspeedtest and netperfrunner.sh scripts let you ping a router if you want, which is what I started off my testing with. You can get a nice low minimum but I don't really trust that now. By default they ping a local google IP, which might give more consistent results. >> Ping in parallel to TCP is a hacky way to measure latencies; not only because of prioritization, but also because you don't measure TCP send/receive buffer latencies (and they can be large, auto-tuning is not so great.) > I guess the concurrent ICMP echo requests are a better measure for flow separation and sparse-flow-boostiing than inter-flow latency. TCP embedded timestamps would be a jacky way to measure those ;) . +1 > >> You really need to embed timestamps in the TCP bytestream and echo them back. See the recent netperf patch I sent. > I hope this makes into the main netperf branch… > > Best Regards > Sebastian >