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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoPlainText>From earlier notes in the list, and from the CeroWRT Wiki, I believe the intent is to back port SQM into OpenWRT.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>As there are a wide variety of hardware platforms supported under OpenWRT, if SQM scripts, and a Luci-App-SQM, then many installed base routers, and readily available routers would greatly benefit.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>I may be misunderstanding, but I thought this was a goal. Am I incorrect, or have the plans changed?<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Also, I do have some questions.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText style='margin-left:.5in;text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:Symbol'><span style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]>I believe fq-codel is integrated into the latest available versions of Linux. If so, other than setting upload and download limits, do we already have buffer control handled with all newer OpenWRT releases?<o:p></o:p></p><p class=MsoPlainText style='margin-left:.5in;text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:Symbol'><span style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]>If so, do we still need to download and configure the packages, QOS-Scripts, and Luci-App-Qos? If so, do these packages do anything besides allow the configuration of Upload and Download limits?<o:p></o:p></p><p class=MsoPlainText style='margin-left:.5in;text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:Symbol'><span style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]>If we can, in fact, control bufferbloat with OpenWRT and the latest Qos-scripts and Luci-App-QOS, then would the integration of SQM into OpenWRT provide much benefit in controlling bloat? If so, are there still plans to make that happen.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>I am very happy with the configuration of my home router running CeroWRT on a Netgear WNDR-3800 (running close to the latest build), on a Verizon FIOS connection at 75 Mbs Down / and 75 Mbs Up, and on running pings with Speedtest notice a definate difference in latency (very tight control) vs up to 100 ms latency.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Thanks to all for the good work, and I hope that these are useful questions.<o:p></o:p></p><p class=MsoPlainText>Frits<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>-----Original Message-----<br>From: cerowrt-devel-bounces@lists.bufferbloat.net [mailto:cerowrt-devel-bounces@lists.bufferbloat.net] On Behalf Of cerowrt-devel-request@lists.bufferbloat.net<br>Sent: Sunday, August 24, 2014 2:55 PM<br>To: cerowrt-devel@lists.bufferbloat.net<br>Subject: Cerowrt-devel Digest, Vol 33, Issue 23</p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Send Cerowrt-devel mailing list submissions to<o:p></o:p></p><p class=MsoPlainText> <a href="mailto:cerowrt-devel@lists.bufferbloat.net"><span style='color:windowtext;text-decoration:none'>cerowrt-devel@lists.bufferbloat.net</span></a><o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>To subscribe or unsubscribe via the World Wide Web, visit<o:p></o:p></p><p class=MsoPlainText> <a href="https://lists.bufferbloat.net/listinfo/cerowrt-devel"><span style='color:windowtext;text-decoration:none'>https://lists.bufferbloat.net/listinfo/cerowrt-devel</span></a><o:p></o:p></p><p class=MsoPlainText>or, via email, send a message with subject or body 'help' to<o:p></o:p></p><p class=MsoPlainText> <a href="mailto:cerowrt-devel-request@lists.bufferbloat.net"><span style='color:windowtext;text-decoration:none'>cerowrt-devel-request@lists.bufferbloat.net</span></a><o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>You can reach the person managing the list at<o:p></o:p></p><p class=MsoPlainText> <a href="mailto:cerowrt-devel-owner@lists.bufferbloat.net"><span style='color:windowtext;text-decoration:none'>cerowrt-devel-owner@lists.bufferbloat.net</span></a><o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>When replying, please edit your Subject line so it is more specific than "Re: Contents of Cerowrt-devel digest..."<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Today's Topics:<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText> 1. SQM vs DSL (Sebastian Moeller)<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>----------------------------------------------------------------------<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Message: 1<o:p></o:p></p><p class=MsoPlainText>Date: Sun, 24 Aug 2014 20:54:49 +0200<o:p></o:p></p><p class=MsoPlainText>From: Sebastian Moeller <<a href="mailto:moeller0@gmx.de"><span style='color:windowtext;text-decoration:none'>moeller0@gmx.de</span></a>><o:p></o:p></p><p class=MsoPlainText>To: Dave T?ht <<a href="mailto:dave.taht@gmail.com"><span style='color:windowtext;text-decoration:none'>dave.taht@gmail.com</span></a>>, cerowrt-devel<o:p></o:p></p><p class=MsoPlainText> <<a href="mailto:cerowrt-devel@lists.bufferbloat.net"><span style='color:windowtext;text-decoration:none'>cerowrt-devel@lists.bufferbloat.net</span></a>><o:p></o:p></p><p class=MsoPlainText>Subject: [Cerowrt-devel] SQM vs DSL<o:p></o:p></p><p class=MsoPlainText>Message-ID: <<a href="mailto:7E74D1C2-5686-40C4-813B-23BE96D736E5@gmx.de"><span style='color:windowtext;text-decoration:none'>7E74D1C2-5686-40C4-813B-23BE96D736E5@gmx.de</span></a>><o:p></o:p></p><p class=MsoPlainText>Content-Type: text/plain; charset="windows-1252"<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Hi Dave, hi List,<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>to avoid real work I embarked on a (quick) test of my DSL line?s bloat (again). Since I just realized that my ISP has increased my per-packet overhead from 40 bytes to 44 bytes (probably by switching onto a platform that uses VLAN tags between DSL-modem and DSLAM/BRAS, but I digress) my recent netperf-wrapper tests all had been invalidated, since most likely the link layer encapsulation was wrong. So I set out to figure out how close I can shape my DSL line ad still keep decent behavior under load. I used Toke?s great netperf-wrapper (the RRUL test to be precise) against netperf-eu.bufferbloat.net and tested a number of different up- and downstream shaping values (on an ATM based adsl2+ line with a line rate of 17613Kbps down and 2604 Kbps up, for all tests the proper link layer encapsulation (ATM with overhead 44) has been used) from a macbook attached via the 5GHz radio. <o:p></o:p></p><p class=MsoPlainText> The first interesting result is that for my line shaping the upstream to 2000Kbps (76%) actually shows no better ICMP-CDF than shaping to 2575Kbps (98.9%) or even 2604 (100%) independent of the shaping of the downstream. Actually, the slower the uplink gets the larger the average latency gets, just as the upstream target value increases to counter the longer transfer times ("tc -d qdisc? on cerowrt will tell the actual effective target values).<o:p></o:p></p><p class=MsoPlainText> Downstream shaping results however are more interesting and less clear.<o:p></o:p></p><p class=MsoPlainText> Attached are three plots of a number of experiments with different downstream-shaping values from 8000 Kbps (8000KU2604K in the legend) up to the line-rate at 17613Kbps (17613KU2604K) to no shaping (0KU0K, that is SQM configured with 0 for up- and downstream). It is quite obvious that no shaping has the highest good-put but at a terrible latency cost (and the DSL-modem is not terribly over-buffered with 85% of the ICMP CDF still below 100ms, but several excursions into the >1000ms range). All downstream shaping values at this overview scale show a massive improvement of latency under load.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText> The second plot (*ping_box_scaled.png) shows once more that no shaping is bad for latency under load (from left to right UDP BE, UDP BK, ICMP, UDP EF, averages). Also quite obvious, shaping the downstream just to line rate (gray box: 17613, 100%) still does not give too good a result with lots of variability (but way better than no shaping). Decreasing the downstream further improves the averages for all latency probes but relatively mild compared to the no-shaping and 100% line-rate shaping conditions. After the tests I converged on 15852 (90%) and 2575 (99%) which on average shows a increase of latency under load of 15ms pretty close to the theoretical expected value of 10ms (5ms codel target in each direction), which given the access via WLAN is quite decent. (Also a wired test afterwards showed an average increase go 11ms close enough to theory to call it a day.)<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText> I guess the 2 interesting points are: <o:p></o:p></p><p class=MsoPlainText>1) With a non-congested DSLAM, DSL upstream shaping can be pushed to the extreme of 100% of line rate without having to pay a severe price in latency growth under load. (I remember that we had a discussion that DSL-modems should learn fq_codel so we could regain the lost upstream bandwidth; I guess with proper handling of the encapsulation there is no bandwidth left on the table ;) Still it would be so much nicer if all modems would do this by themselves). <o:p></o:p></p><p class=MsoPlainText>2) On the downstream side of shaping, it really seems to be a question of figuring out which trade-off between bandwidth and latency under load one is willing to accept. (And finally note to self, perform future tests with a wired connection until wifi is fast ;) )<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText> P.S.: I hope the images are not too large and still readable.<o:p></o:p></p><p class=MsoPlainText>Best Regards<o:p></o:p></p><p class=MsoPlainText> Sebastian<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>-------------- next part --------------<o:p></o:p></p><p class=MsoPlainText>An HTML attachment was scrubbed...<o:p></o:p></p><p class=MsoPlainText>URL: <<a href="https://lists.bufferbloat.net/pipermail/cerowrt-devel/attachments/20140824/63b73396/attachment.html"><span style='color:windowtext;text-decoration:none'>https://lists.bufferbloat.net/pipermail/cerowrt-devel/attachments/20140824/63b73396/attachment.html</span></a>><o:p></o:p></p><p class=MsoPlainText>-------------- next part --------------<o:p></o:p></p><p class=MsoPlainText>A non-text attachment was scrubbed...<o:p></o:p></p><p class=MsoPlainText>Name: dsl_shaping_140824_totals.png<o:p></o:p></p><p class=MsoPlainText>Type: image/png<o:p></o:p></p><p class=MsoPlainText>Size: 58371 bytes<o:p></o:p></p><p class=MsoPlainText>Desc: not available<o:p></o:p></p><p class=MsoPlainText>URL: <<a href="https://lists.bufferbloat.net/pipermail/cerowrt-devel/attachments/20140824/63b73396/attachment.png"><span style='color:windowtext;text-decoration:none'>https://lists.bufferbloat.net/pipermail/cerowrt-devel/attachments/20140824/63b73396/attachment.png</span></a>><o:p></o:p></p><p class=MsoPlainText>-------------- next part --------------<o:p></o:p></p><p class=MsoPlainText>A non-text attachment was scrubbed...<o:p></o:p></p><p class=MsoPlainText>Name: dsl_shaping_140824_ping_box_scaled.png<o:p></o:p></p><p class=MsoPlainText>Type: image/png<o:p></o:p></p><p class=MsoPlainText>Size: 88710 bytes<o:p></o:p></p><p class=MsoPlainText>Desc: not available<o:p></o:p></p><p class=MsoPlainText>URL: <<a href="https://lists.bufferbloat.net/pipermail/cerowrt-devel/attachments/20140824/63b73396/attachment-0001.png"><span style='color:windowtext;text-decoration:none'>https://lists.bufferbloat.net/pipermail/cerowrt-devel/attachments/20140824/63b73396/attachment-0001.png</span></a>><o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>------------------------------<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>_______________________________________________<o:p></o:p></p><p class=MsoPlainText>Cerowrt-devel mailing list<o:p></o:p></p><p class=MsoPlainText><a href="mailto:Cerowrt-devel@lists.bufferbloat.net"><span style='color:windowtext;text-decoration:none'>Cerowrt-devel@lists.bufferbloat.net</span></a><o:p></o:p></p><p class=MsoPlainText><a href="https://lists.bufferbloat.net/listinfo/cerowrt-devel"><span style='color:windowtext;text-decoration:none'>https://lists.bufferbloat.net/listinfo/cerowrt-devel</span></a><o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>End of Cerowrt-devel Digest, Vol 33, Issue 23<o:p></o:p></p><p class=MsoPlainText>*********************************************<o:p></o:p></p></div></body></html>