From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.17.22]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id ADCEF21F1FB for ; Fri, 19 Jun 2015 13:37:19 -0700 (PDT) Received: from hms-beagle-7.home.lan ([217.237.70.193]) by mail.gmx.com (mrgmx101) with ESMTPSA (Nemesis) id 0M97Nh-1ZGAq63Kaz-00CTBS; Fri, 19 Jun 2015 22:37:15 +0200 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) From: Sebastian Moeller In-Reply-To: Date: Fri, 19 Jun 2015 22:37:14 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: <26463A88-821B-44B7-A728-64BCB0B7C7BB@gmx.de> To: Alan Jenkins X-Mailer: Apple Mail (2.1878.6) X-Provags-ID: V03:K0:cjDWH3OWb853R6PSgMiOHYOG7+4Gch0NPmCP6TP1pDHerFlk1/I JVSm2CAUqgkYadPxvMXTfHLeXZPpR0DyyVnqMbXVku7czYMWS8Emur7EOY8r5PuNvnERamF rYFiJLClnh/No/OTnTXhQ5Jttdo0Q8/ItLkjacOKQLhOewwn2l6cYaUhfpYV8bvC38f7qAD gUElaO2YRZlDJDi+Imz/A== X-UI-Out-Filterresults: notjunk:1;V01:K0:wo4N0s1U0Mw=:6mkPGiuLNuOMWgaeb+HCnQ BOnSd2HbckzCgpvbfr7LVdq7mqNilo9jfTgC+wvNTroUmtvyG1nmJC7toOH0BjYn3Zm17WwEO /6rgLv5SCDAIKdZk5fby3J5UDvbz3yWixiWFijwKLvn8jpSSgJpGe2WndnSr2Sy/oACVTa489 Lsl09E10rM47B3fLMTJxSNM8arMG8R1LQDCVChG0YrmqVgb/BM+zzzkEMyKzQDMTRAXbWk4A6 oQ3sS88GcsBVckO2HGTczwPR+YHJnKXV29LKxZkTfNjdVhhr7UYY4/4ZJJghI9SzNUcpcCtwN 5jGOukOEOd0z7fIptqIynZ1IJtvQN4dPy42ctu+oiYIgNSD8116JHzDuNKmKQeP+B085AuR+Q gYOhNLFqGSExXxDmwvH3Oz47wWwxSJI4BLIdADGvAfsTUXVmSwYxilk6Xvd4GRrzZ0T4bJv0r CauxrqKW9XVpRgemctE6/Bx5Ths4pgRyVXQtlhPxKPJHjNOKEpF7hpNm3KML+crCC1s90+yr8 C7Fw37NshcV2bdRlf4pggJeVggG2D1rIzKZ9kJm2+Mw/06lwgeH/2AyTePL0xXSaInkyYS4XR OJyM9hSrlJe21ANQaV+ZvHPZVJt6rlxF4gDDuRAKTt++enAz/B1gSZ7iQAvIwkJ8ffWB1EKN8 hxveFqY8I3iSCt5D4rFeuM2+XRgZrgdjGK6zQ7tOmrrM+lZi5nx9YyE28ub5ulPSDPlE= Cc: Jonathan Morton , cerowrt-devel Subject: Re: [Cerowrt-devel] Latest build test - new sqm-scripts seem to work; "cake overhead 40" didn't 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, 19 Jun 2015 20:37:48 -0000 Hi Alan, On Jun 19, 2015, at 19:35 , Alan Jenkins = wrote: > On 19/06/2015, Sebastian Moeller wrote: >> Hi Alan, >>=20 >> excellent, thanks a million. >>=20 >> On Jun 19, 2015, at 16:44 , Alan Jenkins >> wrote: >>=20 >>> Hi >>>=20 >>> I guess I've done the complementary half to Seb's test :). = Basically >>> "cake overhead 40" didn't work, but that's the fault of cake in this >>> build. Or tc, as Johnathan suggested. (The "cake atm" part seems = to >>> work, as per my previous test). >>=20 >> Great! >>=20 >>>=20 >>> "tc qdisc" says "cake overhead 0", as Sebastian noticed. And the = test >>> results show "cake overhead 40" does not give a measurable >>> improvement. But "tc stab overhead 40" does. >>>=20 >>> I ran this test with the updated sqm-scripts and I think they're = doing >>> the right thing. >>=20 >> Thanks for testing this, especially as I can not due to a lack = of an >> ADSL-link (and lack of cake actually, last I looked all I could find = was >> cookies in my browser and a promise of pie in my router) >>=20 >>>=20 >>>=20 >>> Method: >>>=20 >>> I used the updated files from sqm-scripts, >>>=20 >>> (once I remembered to mark them executable. Lacking that causes a >>> failure with no error messages, because sqm-scripts checks before >>> running them :) >>>=20 >>> but didn't bother updating & using luci-app-sqm. >>=20 >> Ah, okay, I guess I did test this part with Dave=92s help, so = this should >> work with the most recent sqm.lua. >>=20 >>>=20 >>> The test was to compare netperf-runner results - ping during = combined >>> upload & download - for "overhead 40" and "overhead 0". I tested = both >>> values of linklayer_adaptation_mechanism. >>>=20 >>> I had to repeat 6 times (60s per run for each overhead) because of >>> random variation in the range of 3-4ms. I alternated "overhead 40" >>> and "overhead 0" to try and exclude longer-term variation effects. >>>=20 >>> With "stab overhead 40", median latency was better by about 3-4ms. >>> With "cake overhead 40", there is no such effect. >>=20 >> Intersting, when I still had a 6M/1M ADSL link, I saw much = larger latency >> under load increases when setting the per packet overhead to small, = but I >> had my egress shaper running at 100% of line rate, so the system was = rigged >> for maximum effect that way. How are your shapers typically set? >=20 > For this test I try to push it, today I used 95%. I started trying > 100%, which is still much better than unshaped. I was scared off by > the random variation, I think it was higher at 100%. Fair enough, but only at 100% you will notice if the overhead is = off by a single byte=85 You are running sqm on the pppoe interface, = correct? >=20 > For long term use I reduce it, because I've seen the line rate vary > slightly. (1020k up today, 912 a while back. Currently it reports a > "max" figure I don't understand, it's about 1100 despite being > rebooted daily. 16390k down). A pity that your line is that flaky, but it only differs between = reboots and does not change during the day? As far as I know only SRA = would allow rate changes while the sync stays up. So you either have = unscheduled resyncs during the day which drag in a rate change or = between days. Anyway aiming with the shaper rate at below the best case = sync seems wise unless you want to fiddle with modem and router daily. = (It would be sweet if one could query the actual sync speed from = XDSL-modems from the LAN side in a standardized fashion, so sqm could = learn to set the shaper automatically). Best Regards Sebastian >=20 > Alan