From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ia0-f175.google.com (mail-ia0-f175.google.com [209.85.210.175]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 9B75D21F18C for ; Fri, 21 Dec 2012 02:32:32 -0800 (PST) Received: by mail-ia0-f175.google.com with SMTP id z3so3710911iad.6 for ; Fri, 21 Dec 2012 02:32:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=DF+t2dHVePLazZlpOxU/8TSnyQwz8R1a7uLFW0XLdWk=; b=BoenempNxg1W4Fp8p4xOuIxzwC4lG+9EqtKG/wTs2yeWTsGgLMl5AHJ86fzcyRNo5I q/s7TfGwff+tqfX4NvSHGQM/A+LjV1uvY/HAP4Bo0xFsVROZ+EuVzp4Y7NyS6rlYQow/ Xo3ECoBUfFpkO0nRQNzd6z9Co5GHiFGNK56CzljpECCnj7nBEXTjEzxZSv/lwyj//lMM 6FmMOa7FqovMJvo1LjiuffD9yfxTbtKvNrgWPLHzDmXBjAs3sGZYXhX3dKPdGOQYYnoL bGM4vCZuJaLrvDKqFODOZyjJ8JZNgFvds0Aqx0sYm1ZqITNeo7Lgc0kPctHECZ6u9lT4 xmAg== MIME-Version: 1.0 Received: by 10.42.215.10 with SMTP id hc10mr11395583icb.19.1356085951721; Fri, 21 Dec 2012 02:32:31 -0800 (PST) Received: by 10.64.135.39 with HTTP; Fri, 21 Dec 2012 02:32:31 -0800 (PST) In-Reply-To: References: Date: Fri, 21 Dec 2012 05:32:31 -0500 Message-ID: From: Dave Taht To: Alessandro Bolletta Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Cc: "Codel@lists.bufferbloat.net" Subject: Re: [Codel] R: Making tests on Tp-link router powered by Openwrt svn X-BeenThere: codel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: CoDel AQM discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 Dec 2012 10:32:32 -0000 On Fri, Dec 21, 2012 at 5:19 AM, Alessandro Bolletta wrote: > Hi jonathan, > > > > This is how i configured the testbed: > > > > I have a windows 8 laptop connected directly on the tplink/openwrt router= . > Tplink is also connected to a gigabit switch. > > So, i thought to make some file uploads from a linux samba file server > connected to the switch to my windows 8 laptop, through SMB protocol (whi= ch > uses TCP). > > > > In order to create the bottleneck, tplink router has two 10/100mbits port= s. > So, i restricted the port connected to the switch to 10Mbit half duplex. Full duplex is the only thing we've ever tested. Secondly what you are doing here is moving the buffering into the switch. If you want to rate limit, use HTB. Either the simple_qos.sh or qos-scripts can be used for this. http://www.bufferbloat.net/projects/codel/wiki/Best_practices_for_benchmark= ing_Codel_and_FQ_Codel > Also, i tried to decrease interval and target options in order to obtain = a > latency, for connections estabilished while upload is flowing, lower that= 5 > ms. > > So i set target at 2ms and interval to 5ms. You are misunderstanding target and interval. These control the algorithm for determining when to drop. interval is set to 100ms by default as to try to find a good estimate for the RTT, and target to 5ms as to have a goal for a maximum delay to aim for. These values work well down to about 4Mbits, at which point we have been bumping target up in relation to how long it takes to deliver a packet. A value I've been using for target at 1Mbit has been 20, as it takes 13ms to deliver a large packet. The way interval works is that once you've been consistently over the target delay for the interval, the codel drop scheduler starts and you drop a packet. If you are still over the delay for the interval/2, drop another packet, if you are still over the delay for the next interval/3 drop another packet. when you hit an ideal drop rate, stop decreasing the interval. Thank you for giving me a new thing to add to the above url. > > So this is the schema: > > > > laptop----tplink---switch---linuxserver > > > > where tplink is routing subnets. > > > > If i ping =93linux server=94 i get very high latencies=85and if i ping ot= her PCs > connected to the switch, i get about 10ms latencies. > > > > I also tried to lower target at 1 ms and interval at 2ms, but i see the s= ame > effects. > > > > If i disable fq_codel, i get always the same result. you've moved the buffering into the switch. don't do that. > > > > Can you explain me where i=92m going wrong? > > > > Thanks > > > > Da: Jonathan Morton [mailto:chromatix99@gmail.com] > Inviato: gioved=EC 20 dicembre 2012 19.08 > A: Alessandro Bolletta > Cc: Codel@lists.bufferbloat.net > Oggetto: Re: [Codel] Making tests on Tp-link router powered by Openwrt sv= n > > > > Is the bottleneck actually at your router, or (as is more usual) at the > modem? > > - Jonathan Morton > > On Dec 20, 2012 7:57 PM, "Alessandro Bolletta" > wrote: > > Hi everybody, > Today i made some tests on my tplink home router powered by the lastest > snapshot build of Openwrt. > So, i configured tc to make fq_codel the default queuing algorithm for 2 = eth > ports available on the router (leaving unchanged default values). > So, i started some TCP sessions through my Windows client and I loaded th= e > available bandwidth...but the test wasn't going as expected because i > experienced packet loss and high delays as i did when the default simple > fifo queue was the default queue. > Is there something that i'm not understanding? > > Thanks, > Alessandro Bolletta > _______________________________________________ > Codel mailing list > Codel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/codel > > > _______________________________________________ > Codel mailing list > Codel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/codel > --=20 Dave T=E4ht Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.= html