OK, I tried a few combinations of burst and cburst on a cerowrt box, using 90/10 as a up/download speed.
burst 64000 cburst 64000 was a bit of a win, in most respects, but odd in others. netperf-wrapper data at: http://snapon.lab.bufferbloat.net/~d/burst_tests/ On Mon, Oct 20, 2014 at 1:04 PM, Dave Taht <[email protected]> wrote: > On Sun, Oct 19, 2014 at 3:44 PM, Sebastian Moeller <[email protected]> wrote: >> Hi Dave, >> >> so I just went with what I have available, shaping between linux host on >> se00 and macbook on sw10, shaper on se00 (25M/25M that is the maximum >> wireless throughput with the current router position): burst/cburst set at >> 1600(default) 16000 and 16000. And lo and behold the sirq gets smaller the >> larger burst/cburst is set. Now tho test is just too confounded by my bad >> wireless to be proof, but it certainly justifies the time to expose knobs in >> the GUI to set burst/cburst/quantum values for HTB for each shaper instance >> independent for ingress and egress… (I do not assume that this will even >> double the throughput of a wndr as a router, but even just 10-20% will make >> a difference ;) (I will eat my own dogwood, since I am about to upgrade from >> 16M/2.5M to 50M/10M right into where our sirq pain starts)). > > I don't necessarily think knobs need to be exposed. Perhaps tuning the > burst parameter as a function of the > induced latency would be about right. At 10mbits, a single 1500 byte > packet takes 1.3ms to egress. So if we > were to aim for .5-2ms worth of burst across the operational range of > the shaper, that might work. In the > case of cable, a grant request takes 2-6ms, anyway. > > So at 80mbit, a burst size of 8-16k seems possibly optimal. It could > be higher (other overheads in the kernel). > > Now that we have a knob to jiggle, I'll go jiggle it when I have some time... > > I note that I'm under the impression cburst can be twiddled with also > to make "powerboost"'s behavior better, > but I've not seen it work. >> >> >> >> Best Regards >> Sebastian >> >> On Oct 19, 2014, at 21:27 , Dave Taht <[email protected]> wrote: >> >>> Yes fiddling with burst seems to make sense. Try 16k >>> >>> On Oct 19, 2014 11:56 AM, "Sebastian Moeller" <[email protected]> wrote: >>> HI Dave, >>> >>> >>> On Oct 19, 2014, at 20:24 , Dave Taht <[email protected]> wrote: >>> >>> > On at least one verizon device I've tried it appeared that they had >>> > SFQ or something similar on egress from the modem. >>> > >>> > http://www.bufferbloat.net/projects/codel/wiki/RRUL_Rogues_Gallery#Verizon-FIOS-Testing-at-25Mbit-up-and-25Mbit-down >>> > >>> > So you only needed to shape the download. which is good as we start >>> > peaking out at 50Mbit download total. But only measurements can tell. >>> >>> So on Hnymans community openwrt build a few fortunate ones on >>> excellent lines seem to get decent results even at 110-120 Mbps combined: >>> https://forum.openwrt.org/viewtopic.php?pid=250989#p250989 >>> and: >>> https://forum.openwrt.org/viewtopic.php?pid=251013#p251013 >>> I have no idea why and both lines were reasonably well-behaved even without >>> any AQM/QOS... >>> >>> Also I wonder whether when we increase the quantum for higher rates to give >>> HTB some breathing room, whether we also should increase burst and cburst? >>> My hunch is that quantum affects the switching between the leaves, while >>> busts and cburst should allow to dump more data to lower layers inside each >>> leaf qdisc. And since we are running behind, maybe taking a bigger shovel >>> can help some. (I assume this needs to be titrated not to kill latency >>> under load, but if we can only effective have HTB execute x times per >>> second we can easily afford to dump line-rate/maxHTB_iteratin_rate bytes >>> per opportunity, no?) My own internet link is way to slow to test this... >>> >>> Best Regards >>> Sebastian >>> >>> > >>> > >>> > On Sun, Oct 19, 2014 at 10:51 AM, Ernesto Elias <[email protected]> >>> > wrote: >>> >> Hello everyone! >>> >> I have a question about the wndr3800 routing limit. I went back to the >>> >> older >>> >> submissions to see if I can find what would be the answer for it. But in >>> >> my >>> >> search I haven't managed to find a definite answer. From what I seen >>> >> about >>> >> setting the limit it can do with SQM is 50, 60, or 80 mbit. I'm just >>> >> wondering if anyone can shed some light for me here as I have verizon >>> >> fios >>> >> and my speeds are 50 dl/50 ul. Thank you guys very much! >>> >> >>> >> _______________________________________________ >>> >> Cerowrt-devel mailing list >>> >> [email protected] >>> >> https://lists.bufferbloat.net/listinfo/cerowrt-devel >>> >> >>> > >>> > >>> > >>> > -- >>> > Dave Täht >>> > >>> > thttp://www.bufferbloat.net/projects/bloat/wiki/Upcoming_Talks >>> > _______________________________________________ >>> > Cerowrt-devel mailing list >>> > [email protected] >>> > https://lists.bufferbloat.net/listinfo/cerowrt-devel >>> >> > > > > -- > Dave Täht > > thttp://www.bufferbloat.net/projects/bloat/wiki/Upcoming_Talks -- Dave Täht thttp://www.bufferbloat.net/projects/bloat/wiki/Upcoming_Talks _______________________________________________ Cerowrt-devel mailing list [email protected] https://lists.bufferbloat.net/listinfo/cerowrt-devel
