Hi Loganaden, > On Jul 19, 2016, at 10:09 , Jonathan Morton <chromati...@gmail.com> wrote: > > >> On 19 Jul, 2016, at 07:29, Loganaden Velvindron <logana...@gmail.com> wrote: >> >> I've been playing with fq_codel on 3g internet connection. the 3g >> internet box has no bridge mode, and just forwards every packet to the >> Openwrt router. >> >> Here are the results without: >> http://www.dslreports.com/speedtest/4470186 >> >> And here is the result with fq_codel on and 300 ms target latency: >> >> http://www.dslreports.com/speedtest/4470286 >> >> Is there anything that could be done to get the rating up to A+ by >> tweaking the code ? > > You say fq_codel, rather than Cake. Presumably it is paired with some sort > of shaper, such as HTB? This is important, because I think the shaper is > influencing part of your results. > > On downstream, you have one high latency sample (750ms) in the middle of a > series of reasonable ones (250ms). This implies a momentary glitch in your > connection, which isn’t unusual with wireless links. Re-measuring might > eliminate it. > > On upstream, you have two very high latency samples at the *beginning* of the > run, which then clear out to approximately the baseline latency. This is a > classic sign that your shaper is letting a burst of traffic through before > actually starting to control it, which is typical behaviour for token-bucket > shapers. That initial burst collects in the dumb queue of your 3G modem and > takes time to drain away. > > Cake uses a shaper carefully designed to *not* burst in that manner, while > still maintaining full throughput regardless of timer resolution and latency. > Using Cake instead of fq_codel+HTB will therefore probably improve your > upload characteristics.
I believe that the way sqm-scripts simple.qos and simplest.qos use the HTB shaper are not subject to this specific issue (we do not configure/allow HTB to burst at all). Looking at a number of my speed tests seems to support this observation (https://www.dslreports.com/speedtest/636817 simplest.qos, HTB+fq_codel no initial bursting). Best Regards Sebastian > > - Jonathan Morton > > _______________________________________________ > Cake mailing list > Cake@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cake _______________________________________________ Cake mailing list Cake@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/cake