On Mon, Jan 18, 2016 at 12:29 PM, Jonathan Morton <chromati...@gmail.com> wrote: > >> On 18 Jan, 2016, at 11:43, Valent Turkovic <val...@otvorenamreza.org> wrote: >> >> Can you please share your sqm qos script, or just how you invoke tc >> manually and I'll test it on my routers and see what happens then:) > > The autorate_ingress option is just a flag. Specify it after the bandwidth > parameter to give it a sane starting point, say 1Mbit. I think some of the > more recent GUIs have a field for “advanced” or “experimental” options like > this. Once it sees some traffic, it should settle down reasonably quickly to > the real link capacity, minus a small margin to establish itself as the > bottleneck. > > Eg: tc qdisc replace dev ifb0 root cake bandwidth 1Mbit autorate_ingress
# tc qdisc replace dev eth0.2 root cake bandwidth 1Mbit autorate_ingress Unknown qdisc "cake", hence option "bandwidth" is unparsable So this is the reason I saw "bad" results when using cake... cake qdisc isn't even available in latest Chaos Chalmer... but Luci shows it as an option, really strange. Cake script [1] is located in /usr/lib/sqm/piece_of_cake.qos but there is no cake kernel module as far as I can see: # opkg list | grep sched kmod-sched - 3.18.20-1 - Extra kernel schedulers modules for IP traffic kmod-sched-connmark - 3.18.20-1 - Traffic shaper conntrack mark support kmod-sched-core - 3.18.20-1 - Core kernel scheduler support for IP traffic kmod-sched-esfq - 3.18.20-1 - Traffic shaper ESFQ support Again trough accidental discovery it looks like ESFQ [2] would also be an nice addition to codel. How about efq_codel insead of fq_codel ? Has anybody tried using ESFQ with codel? But back to OpenWrt... are there Cake packages for OpenWrt available anywhere? > As a reminder, autorate_ingress only works *downstream* of the bottleneck > link. Use it on the external interface’s *ingress* if possible. > I'll try this as soon as I get cake working on OpenWrt... >> From your presentation I see that if we had a daemon working in >> background and somehow measured tcp latency (how?) and then we could >> use it to raise/lower bandwidth limits on cake until we get best >> possible results. Ideally I would like to use a queueing mechanism >> that auto-configures everything. > > Right. The autorate_ingress feature works entirely in kernelspace, and > effectively takes care of the downstream half of the equation. The upstream > half turns out to be a much harder problem, because we can only measure the > uplink capacity when it is saturated, and typical consumer traffic doesn’t do > that very often. If we did have a saturating bulk upstream TCP flow, then we > could examine its RTT profile in userspace, under the assumption that the > downlink was taken care of. > > One reasonable approach might be to use a userspace tool to periodically > scrape the downlink speed out of autorate_ingress, and set the uplink speed > to some fixed fraction of that (using tc qdisc change, for least disruption). > It might even make sense for 3G to inherently have such a ratio. If it > does, does anyone know what it is? > >> @everybody any ideas how to tweak current "simple.qos" and >> "simplest.qos" scripts in OpenWrt for 3G and fiber optics? On fiber >> optic connection idle latency is around 30ms and on 3G connection is >> around 60ms, do I need to change 5ms default in fq_codel to these >> values? How? > > These are essentially internet-scale latencies, especially if you’re just > pinging the gateway immediately beyond the link, so the defaults will work > fine. The most recent versions of tc-adv include a set of intuitive keywords > to specify commonly-encountered RTT ranges; the one for “internet” is 100ms, > which corresponds to the Codel default parameters. > > The 5ms figure is the target *queuing* latency, which should be considerably > less than the estimated RTT; you really don’t want to be consistently adding > 60ms of queuing on top of your 60ms inherent 3G latency. Thanks! _______________________________________________ Cerowrt-devel mailing list Cerowrt-devel@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/cerowrt-devel
