The rule of thumb for fixing downloads is to start at 85% of your rated dl and try to get to 95%. It is unfortunately very subject to the RTT of your last hop, which on DSL is quite a lot, so I would be surprised if you could crack 90%. Cutting it by 50% is a bit much tho! (It would, as always, be best if the provider used something fq_codel like on their rate limiter, not yours). but I'm glad to hear you are making progress! On Sun, Aug 25, 2013 at 12:08 PM, Fred Stratton wrote: > That is very helpful. > > With a sync rate of about 12000 kbits/s, and a download rate of about > 10900 kbits/s. I have set the download rate to 5000 kbits/s. For upload > similarly 1200/970/500, all kbits/s. > > I can now mostly watch video in iPlayer and download at circa 300 - 400 > kbits/s simultaneously, using htb, with tc-stab disabled. > > QED > > > On 25 Aug 2013, at 19:41, Dave Taht wrote: > > So it sounds like you need a lower setting for the download than what you > are using? It's not the upload that is your problem. > > Netanalyzer sends one packet stream and thus measures 1 queue only. > fq_codel will happily give it one big queue for a while, while still > interleaving other flows's packets into the stream at every opportunity. > > as for parsing rrul I generally draw a line with my hand and multiply by > 4, then fudge in the numbers for the reverse ack and measurement streams. > > > You are saying that you judge the result solely by eye. presumably. > > > As written it was targetted at 4Mbit and up which is why the samples are > discontinuous in your much lower bandwidth situation. > > > Aha. Problem solved. > > > I do agree that rrul could use a simpler implementation, perhaps one that > tested two download streams only, and provided an estimate as to the actual > bandwidth usage, and scale below 4Mbit better. > > > On Sun, Aug 25, 2013 at 11:30 AM, Fred Stratton wrote: > >> >> On 25 Aug 2013, at 18:53, Sebastian Moeller wrote: >> >> > Hi Fred, >> > >> > >> > On Aug 25, 2013, at 16:26 , Fred Stratton wrote: >> > >> >> Thank you. >> >> >> >> This is an initial response. >> >> >> >> Am using 3.10.2-1 currently, with the standard AQM interface. This >> does not have the pull down menu of your interface, which is why I ask if >> both are active. >> > >> > I have seen your follow-up mail that you actually used 3.10.9-2. >> I think that has the first cut of the script modifications that still allow >> to select both. Since I have not tested it any other way I would recommend >> to enable just one of them at the same time. Since the implementation of >> both is somewhat orthogonal and htb_private actually works in 3.10.9, best >> case you might actually get the link layer adjustments (LLA) and the >> overhead applied twice, wasting bandwidth. So please either use the last >> set of modified files I send around or wait for Dave to include them in >> ceropackages… >> >> I have retained the unmodified script. I shall return to that. >> >> >> > >> >> On 25 Aug 2013, at 14:59, Sebastian Moeller wrote: >> >> >> >>> Hi Fred, >> >>> >> >>> >> >>> On Aug 25, 2013, at 12:17 , Fred Stratton >> wrote: >> >>> >> >>>> >> >>>> On 25 Aug 2013, at 10:21, Fred Stratton >> wrote: >> >>>> >> >>>>> As the person with the most flaky ADSL link, I point out that None >> of these recent, welcome, changes, are having any effect here, with an >> uplink sped of circa 950 kbits/s. >> >>> >> >>> Okay, how flaky is you link? What rate of Errors do you have >> while testing? I am especially interested in CRC errors and ES SES and HEC, >> just to get an idea how flaky the line is... >> >>> >> >>>>> >> >>>>> The reason I mention this is that it is still impossible to watch >> iPlayer Flash streaming video and download at the same time, The iPlayer >> stream fails. The point of the exercise was to achieve this. >> >>>>> >> >>>>> The uplink delay is consistently around 650ms, which appears to be >> too high for effective streaming. In addition, the uplink stream has >> multiple breaks, presumably outages, if the uplink rate is capped at, say, >> 700 kbits/s. >> >>> >> >>> Well, watching video is going to stress your downlink so the >> uplink should not saturate by the ACKs and the concurrent downloads also do >> not stress your uplink except for the ACKs, so this points to downlink >> errors as far as I can tell from the data you have given. If the up link >> has repeated outages however, your problems might be unfixable because >> these, if long enough, will cause lost ACKs and will probably trigger >> retransmission, independent of whether the link layer adjustments work or >> not. (You could test this by shaping you up and downlink to <= 50% of the >> link rates and disable all link layer adjustments, 50% is larger than the >> ATM worst case so should have you covered. Well unless you del link has an >> excessive number of tones reserved for forward error correction (FEC)). >> >> >> >> Uptime 100655 >> >> downstream 12162 kbits/s >> >> CRC errors 10154 >> >> FEC Errors 464 >> >> hEC Errors 758 >> >> >> >> upstream 1122 kbits/s >> >> no errors in period. >> > >> > Ah, I think you told me in the past that "Target snr upped to 12 >> deciBel. Line can sustain 10 megabits/s with repeated loss of sync.atlower snr. " so sync at 12162 might be too aggressive, no? But the point is >> that as I understand iPlayer works fine without competing download traffic? >> To my eye the error numbers look small enough to not be concerned about. Do >> you know how long the error correction period is? >> >> The correction period is probably circa 28 hours. Have moved to using the >> HG612. This is uses the Broadcom 6368 SoC. Like most of the devices I use, >> it fell out of a BT van and on to ebay. It is the standard device used for >> connecting FTTC installations in the UK. With a simple modification, it >> will work stably with ADSL2+. >> >> Ihe sync rate has gone up considerably, not because I have changed the >> Target SNR from 12 Decibel, but because I am now using a Broadcom chipset >> and software blob with a DSLAM which returns BDCM when interrogated. >> > >> > >> >> >> >>> Could you perform the following test by any chance: state iPlayer >> and yor typical downloads and then have a look at >> http://gw.home.lan:81und the following tab chain Status -> Realtime >> Graphs -> Traffic -> Realtime Traffic. If during your test the Outbound >> rate stays well below you shaped limit and you still encounter the stream >> failure I would say it is save to ignore the link layer adjustments as >> cause of your issues. >> >> >> >> Am happy reducing rate to fifty per cent, but the uplink appears to >> have difficulty operating below circa 500 kbits/s. This should not be so. I >> shall try a fourth time. >> > >> > That sounds weird, if you shape to below 500 upload stops working >> or just gets choppier? Looking at your sync data 561 would fit the ~50% and >> above 500 requirements. >> >> I was basing the judgment on Netalyzr data. DT and you now say this is >> suspect. However, netsurf-wrapper traces are discontinuous. The actual real >> time trace looks perfectly normal. >> >> iPlayer is a Flash based player which is web page embedded. The ipv4 >> user address is parsed to see if it is in the UK. It plays BBC TV programs. >> It most likely is badly designed and written. It is the way I watch TV. >> Like all UK residents, I pay the bloated bureaucracy of the BBC a yearly >> fee of about 200 euro. If I do not pay, I will be fined. You will be >> surprised that I am not a fan of the BBC. iPlayer starts and runs fine, but >> if a download is commenced whilst it is running, so I can watch the >> propaganda put out as national news, the video will stall and the continue, >> but most commonly will stop. >> > >> > >> >>> >> >>> >> >>>>> >> >>>>> YouTube has no problems. >> >>>>> >> >>>>> I remain unclear whether the use of tc-stab and htb are mutually >> exclusive options, using the present stock interface. >> >>> >> >>> Well, depending on the version of the cerowrt you use, <3.10.9-1 >> I believe lacks a functional HTB link layer adjustment mechanism, so you >> should select tc_stab. My most recent modifications to Toke and Dave's AQM >> package does only allow you to select one or the other. In any case >> selecting BOTH is not a reasonable thing to do, because best case it will >> only apply overhead twice, worst case it would also do the (link layer >> adjustments) LLA twice >> >> >> >> >> >>> See initial comments. >> >>> >> >>>>> >> >>>>> The current ISP connection is IPoA LLC. >> >>>> >> >>>> Correction - Bridged LLC. >> >>> >> >>> Well, I think you should try to figure out your overhead >> empirically and check the encapsulation. I would recommend you run the >> following script on you r link over night and send me the log file it >> produces: >> >>> >> >>> #! /bin/bash >> >>> # TODO use seq or bash to generate a list of the requested sizes (to >> alow for non-equdistantly spaced sizes) >> >>> >> >>> # Telekom Tuebingen Moltkestrasse 6 >> >>> TECH=ADSL2 >> >>> # finding a proper target IP is somewhat of an art, just traceroute a >> remote site >> >>> # and find the nearest host reliably responding to pings showing the >> smallet variation of pingtimes >> >>> TARGET=87.186.197.70 # T >> >>> DATESTR=`date +%Y%m%d_%H%M%S` # to allow multiple sequential >> records >> >>> LOG=ping_sweep_${TECH}_${DATESTR}.txt >> >>> >> >>> >> >>> # by default non-root ping will only end one packet per second, so >> work around that by calling ping independently for each package >> >>> # empirically figure out the shortest period still giving the >> standard ping time (to avoid being slow-pathed by our host) >> >>> PINGPERIOD=0.01 # in seconds >> >>> PINGSPERSIZE=10000 >> >>> >> >>> # Start, needed to find the per packet overhead dependent on the ATM >> encapsulation >> >>> # to reliably show ATM quantization one would like to see at least >> two steps, so cover a range > 2 ATM cells (so > 96 bytes) >> >>> SWEEPMINSIZE=16 # 64bit systems seem to require 16 bytes >> of payload to include a timestamp... >> >>> SWEEPMAXSIZE=116 >> >>> >> >>> >> >>> n_SWEEPS=`expr ${SWEEPMAXSIZE} - ${SWEEPMINSIZE}` >> >>> >> >>> >> >>> i_sweep=0 >> >>> i_size=0 >> >>> >> >>> while [ ${i_sweep} -lt ${PINGSPERSIZE} ] >> >>> do >> >>> (( i_sweep++ )) >> >>> echo "Current iteration: ${i_sweep}" >> >>> # now loop from sweepmin to sweepmax >> >>> i_size=${SWEEPMINSIZE} >> >>> while [ ${i_size} -le ${SWEEPMAXSIZE} ] >> >>> do >> >>> echo "${i_sweep}. repetition of ping size ${i_size}" >> >>> ping -c 1 -s ${i_size} ${TARGET} >> ${LOG} & >> >>> (( i_size++ )) >> >>> # we need a sleep binary that allows non integer times (GNU sleep >> is fine as is sleep of macosx 10.8.4) >> >>> sleep ${PINGPERIOD} >> >>> done >> >>> done >> >>> >> >>> #tail -f ${LOG} >> >>> >> >>> echo "Done... ($0)" >> >>> >> >>> >> >>> Please set TARGET to the closest IP host on the ISP side of your link >> that gives reliable ping RTTs (using "ping -c 100 -s 16 >> your.best.host.ip"). Also test whether the RTTs are in the same ballpark >> when you reduce the ping period to 0.01 (you might have to increase the >> period until the RTTs are close to the standard 1 ping per second case). I >> can then run this through my matlab code to detect the actual overhead. (I >> am happy to share the code as well, if you have matlab available; it might >> even run under octave but I have not tested that since the last major >> changes). >> >> >> >> To follow at some point. >> > >> > Oh, I failed to mention at the given parameters the script takes >> almost 3 hours, during which the link should be otherwise idle... >> > >> >>> >> >>> >> >>>> >> >>>>> Whatever byte value is used for tc-stab makes no change. >> >>> >> >>> I assume you talk about the overhead? Missing link layer >> adjustment will eat between 50% and 10% of your link bandwidth, while >> missing overhead values will be more benign. The only advise I can give is >> to pick the overhead that actually describes your link. I am willing to >> help you figure this out. >> >> >> >> The link is bridged LLC. Have been using 18 and 32 for test purposes. >> I shall move to PPPoA VC-MUX in 4 months. >> > >> > I guess figuring out you exact overhead empirically is going to >> be fun. >> > >> >>> >> >>>>> >> >>>>> I have applied the ingress modification to simple.qos, keeping the >> original version., and tested both. >> >>> >> >>> For which cerowrt version? It is only expected to do something >> for 3.10.9-1 and upwards, before that the HTB lionklayer adjustment did NOT >> work. >> >> >> >> Using 3.10.9-2 >> > >> > Yeah as stated above, I would recommend to use either or, not >> both. If you took RRUL data you might be able to compare the three >> conditions. I would estimate the most interesting part would be in the >> sustained ravager up and download rates here. >> >> How do you obtain an average i.e. mean rate from the RRUL graph? >> > >> > >> >> >> >>> >> >>>>> >> >>>>> I have changed the Powerline adaptors I use to ones with known >> smaller buffers, though this is unlikely to be a ate-limiting step. >> >>>>> >> >>>>> I have changed the 2Wire gateway, known to be heavily buffered, >> with a bridged Huawei HG612, with a Broadcom 6368 SoC. >> >>>>> >> >>>>> This device has a permanently on telnet interface, with a simple >> password, which cannot be changed other than by firmware recompilation… >> >>>>> >> >>>>> Telnet, however, allows txqueuelen to be reduced from 1000 to 0. >> >>>>> >> >>>>> None of these changes affect the problematic uplink delay. >> >>> >> >>> So how did you measure the uplink delay? The RRUL plots you sent >> me show an increase in ping RTT from around 50ms to 80ms with tc_stab and >> fq_codel on simplest.qos, how does that reconcile with 650ms uplink delay, >> netalyzr? >> >> >> >> Max Planck and Netalyzr produce the same figure. I use both, but Max >> Planck gives you circa 3 tries per IP address per 24 hours. >> > >> > Well, both use the same method which is not to meaningful if you >> use fq_codel on a shaped link (unless you want to optimize your system for >> UDP floods :) ) >> > >> > [snipp] >> > >> > >> > Best Regards >> > Sebastian >> >> _______________________________________________ >> Cerowrt-devel mailing list >> Cerowrt-devel@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/cerowrt-devel >> > > > > -- > Dave Täht > > Fixing bufferbloat with cerowrt: > http://www.teklibre.com/cerowrt/subscribe.html > > > > _______________________________________________ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel > > -- Dave Täht Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html