From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.17.21]) (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 107D221F151 for ; Sat, 24 Aug 2013 13:51:41 -0700 (PDT) Received: from hms-beagle-2.home.lan ([79.229.225.62]) by mail.gmx.com (mrgmx103) with ESMTPSA (Nemesis) id 0MRGvT-1Vd08j2sVb-00Ubs5 for ; Sat, 24 Aug 2013 22:51:39 +0200 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 6.5 \(1508\)) From: Sebastian Moeller In-Reply-To: Date: Sat, 24 Aug 2013 22:51:35 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: <56B261F1-2277-457C-9A38-FAB89818288F@gmx.de> <2148E2EF-A119-4499-BAC1-7E647C53F077@gmx.de> <03951E31-8F11-4FB8-9558-29EAAE3DAE4D@gmx.de> <9A9B094D-CA07-48B0-85FE-FA7C759FEDE3@gmx.de> <5BEF0C7C-C2F4-45A9-9FF2-E32A05B8D67B@gmx.de> To: Dave Taht X-Mailer: Apple Mail (2.1508) X-Provags-ID: V03:K0:heZGOKECnFBB8USt1fjnesgyaMiiW+BrwS0PeaJfzCQWydji0cR 6b+0fkNsFflkBaLusfDdlqCpYpkVGcKPprjdieXKIpUKaGKpPDgwYUi+AECTxQ/WDGcdch6 VX1oD1c0VCYhU/sPBYTpT64+LywwN4SmeGtHx7ebMNKs6AvQHF3hXflbUz+RNIXgOJijOCf +Iho2KCmijBLhfsyji5kQ== Cc: Jesper Dangaard Brouer , "cerowrt-devel@lists.bufferbloat.net" Subject: Re: [Cerowrt-devel] some kernel updates X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 24 Aug 2013 20:51:42 -0000 Hi Dave, On Aug 23, 2013, at 22:29 , Dave Taht wrote: >=20 >=20 >=20 > On Fri, Aug 23, 2013 at 12:56 PM, Sebastian Moeller = wrote: > Hi Dave, >=20 > I guess I found the culprit: >=20 > once I added $ADSLL to the ingress() in simple.qos: >=20 >=20 >=20 > I had that in there originally. I ripped it out because it seemed to = help with ADSL at the time - as I was unaware the extent that the whole = subsystem was busted! Ah, and I had added my stab based version to both ingress() and = egress() assuming that both links need to be kept under control. So with = fixed htb link layer adjustment (LLA) it only worked on the uplink and = in retrospect if I look at my initial test data I actually see one of = the hallmarks of a working LLA for the upstream. (The upstream good-put = was reduced compared to the no LLA test, caused by LLA making the = actually sent packets larger so fewer packets fit through the shaped = link). But since I was not expecting only half a working system I = overlooked that in the data. But looking at the latency of the ping RTT probes it becomes = quite clear that only doing link layer adjustments on the uplink is even = worse than not doing it all (because the latency is still almost as bad = as without LLA but the up-link bandwidth is reduced). >=20 > I like to think of the process we've just gone through as "wow, we = just fixed the uk, and a few other countries". :) Feels kind of good, = doesn't it? (Too bad the pay sucks.) Oh, I can not complain about pay, I have a day job in totally = different field, so this is more of a hobby for me :)=20 > I mean, jeeze, chopping another 30+ms off the latency of that many = systems should get medals from economists worldwide monitoring = productivity.=20 >=20 > Does anyone have a date/kernel version on when linklayer overhead = compensation stopped working? There was a bug even prior to 3.8 that = looked bad. (and RED was busted for 3 years). >=20 > Another step would be trying to improve openwrt's native qos system = somewhat in the DSL case. They don't use this subsystem (probably = because it didn't work), and it's also broke on ipv6. (They use conn = track) Oh, in the bql-40 time frame I hacked the stab based LLA into = their generate.sh and it worked quite well, even though at time my = measurements were quite crude. SInce their qos scripts are HFSC based = the HTB private implementation is not going to do them any good. Luckily = now that does not seem to matter as both methods now perform identically = as they should. (Well, now Jespers last changes are nicer than the old = table lookup, but it should be relatively say to implant the same for = stab, heck once I got my linux machine up I might take this as my first = attempt at making local changes to the kernel :) ). So adding it to = openwrt proper should be a piece of cake. Do you know by any chance who = would be the best person to contact for that, ? >=20 > At some point I'd like to have a mechanism for saner diffserv = classification on egress, and to clamp ingress values to egress ones. = There is a ton of work going on on finding sane codepoints on webrtc in = the ietf=85. >=20 >=20 >=20 >=20 >=20 >=20 > ingress() { >=20 > CEIL=3D$DOWNLINK > PRIO_RATE=3D`expr $CEIL / 3` # Ceiling for prioirty > BE_RATE=3D`expr $CEIL / 6` # Min for best effort > BK_RATE=3D`expr $CEIL / 6` # Min for background > BE_CEIL=3D`expr $CEIL - 64` # A little slop at the top >=20 > LQ=3D"quantum `get_mtu $IFACE`" >=20 > $TC qdisc del dev $IFACE handle ffff: ingress 2> /dev/null > $TC qdisc add dev $IFACE handle ffff: ingress >=20 > $TC qdisc del dev $DEV root 2> /dev/null > $TC qdisc add dev $DEV root handle 1: ${STABSTRING} htb default 12 > $TC class add dev $DEV parent 1: classid 1:1 htb $LQ rate ${CEIL}kbit = ceil ${CEIL}kbit $ADSLL > $TC class add dev $DEV parent 1:1 classid 1:10 htb $LQ rate = ${CEIL}kbit ceil ${CEIL}kbit prio 0 $ADSLL > $TC class add dev $DEV parent 1:1 classid 1:11 htb $LQ rate 32kbit = ceil ${PRIO_RATE}kbit prio 1 $ADSLL > $TC class add dev $DEV parent 1:1 classid 1:12 htb $LQ rate = ${BE_RATE}kbit ceil ${BE_CEIL}kbit prio 2 $ADSLL > $TC class add dev $DEV parent 1:1 classid 1:13 htb $LQ rate = ${BK_RATE}kbit ceil ${BE_CEIL}kbit prio 3 $ADSLL >=20 > # I'd prefer to use a pre-nat filter but that causes permutation... >=20 > $TC qdisc add dev $DEV parent 1:11 handle 110: $QDISC limit 1000 $ECN = `get_quantum 500` `get_flows ${PRIO_RATE}` > $TC qdisc add dev $DEV parent 1:12 handle 120: $QDISC limit 1000 $ECN = `get_quantum 1500` `get_flows ${BE_RATE}` > $TC qdisc add dev $DEV parent 1:13 handle 130: $QDISC limit 1000 $ECN = `get_quantum 1500` `get_flows ${BK_RATE}` >=20 > diffserv $DEV >=20 > ifconfig $DEV up >=20 > # redirect all IP packets arriving in $IFACE to ifb0 >=20 > $TC filter add dev $IFACE parent ffff: protocol all prio 10 u32 \ > match u32 0 0 flowid 1:1 action mirred egress redirect dev $DEV >=20 > } >=20 > I get basically the same RRUL ping RTTs for htb_private as for = tc_stab. So Jesper was right the patch seems to fix the issue. I guess I = should send out my current version of yours and Toke's AQM scripts soon. >=20 >=20 >=20 > Best > Sebastian >=20 > P.S.: I am not sure whether I want to tackle the PIE issue today... >=20 >=20 >=20 > On Aug 23, 2013, at 21:47 , Dave Taht wrote: >=20 >> quick note: running this script requires that you >>=20 >> ifconfig ifb0 up >>=20 >> at some point. >=20 > In my case on cerowrt you took care of that already... >=20 >=20 >>=20 >>=20 >> On Fri, Aug 23, 2013 at 12:38 PM, Sebastian Moeller = wrote: >> Hi Dave, >>=20 >> On Aug 23, 2013, at 07:13 , Dave Taht wrote: >>=20 >>>=20 >>>=20 >>>=20 >>> On Thu, Aug 22, 2013 at 5:52 PM, Sebastian Moeller = wrote: >>> Hi List, hi Jesper, >>>=20 >>> So I tested 3.10.9-1 to assess the status of the HTB atm link layer = adjustments to see whether the recent changes resurrected this feature. >>> Unfortunately the htb_private link layer adjustments still is = broken (RRUL ping RTT against Toke's netperf host in Germany of ~80ms, = same as without link layer adjustments). On the bright side the tc_stab = method still works as well as before (ping RTT around 40ms). >>> I would like to humbly propose to use the tc stab method in = cerowrt to perform ATM link layer adjustments as default. To repeat = myself, simply telling the kernel a lie about the packet size seems more = robust than fudging HTB's rate tables. Especially since the kernel = already fudges the packet size to account for the ethernet header and = then some, so this path should receive more scrutiny by virtue of having = more users? >>>=20 >>> It's my hope that the atm code works but is misconfigured. You can = output the tc commands by overriding the TC variable with TC=3D"echo tc" = and paste here. >>=20 >> So I went for TC=3D"logger tc" and used log read to harvest as I = could not find the echo output, but I guess that should not matter. So = here is the result (slightly edited to get rid of the log timestamps and = log level): >>=20 >> tc qdisc del dev ge00 root >> tc qdisc add dev ge00 root handle 1: htb default 12 >> tc class add dev ge00 parent 1: classid 1:1 htb quantum 1500 rate = 2430kbit ceil 2430kbit mpu 0 linklayer adsl overhead 40 mtu 2047 >> tc class add dev ge00 parent 1:1 classid 1:10 htb quantum 1500 rate = 2430kbit ceil 2430kbit prio 0 mpu 0 linklayer adsl overhead 40 mtu 2047 >> tc class add dev ge00 parent 1:1 classid 1:11 htb quantum 1500 rate = 128kbit ceil 810kbit prio 1 mpu 0 linklayer adsl overhead 40 mtu 2047 >> tc class add dev ge00 parent 1:1 classid 1:12 htb quantum 1500 rate = 405kbit ceil 2366kbit prio 2 mpu 0 linklayer adsl overhead 40 mtu 2047 >> tc class add dev ge00 parent 1:1 classid 1:13 htb quantum 1500 rate = 405kbit ceil 2366kbit prio 3 mpu 0 linklayer adsl overhead 40 mtu 2047 >> tc qdisc add dev ge00 parent 1:11 handle 110: fq_codel limit 600 = noecn quantum 300 >> tc qdisc add dev ge00 parent 1:12 handle 120: fq_codel limit 600 = noecn quantum 300 >> tc qdisc add dev ge00 parent 1:13 handle 130: fq_codel limit 600 = noecn quantum 300 >> tc filter add dev ge00 parent 1:0 protocol all prio 999 u32 match ip = protocol 0 0x00 flowid 1:12 >> tc filter add dev ge00 parent 1:0 protocol ip prio 1 handle 1 fw = classid 1:11 >> tc filter add dev ge00 parent 1:0 protocol ip prio 2 handle 2 fw = classid 1:12 >> tc filter add dev ge00 parent 1:0 protocol ip prio 3 handle 3 fw = classid 1:13 >> tc filter add dev ge00 parent 1:0 protocol ipv6 prio 4 handle 1 fw = classid 1:11 >> tc filter add dev ge00 parent 1:0 protocol ipv6 prio 5 handle 2 fw = classid 1:12 >> tc filter add dev ge00 parent 1:0 protocol ipv6 prio 6 handle 3 fw = classid 1:13 >> tc filter add dev ge00 parent 1:0 protocol arp prio 7 handle 1 fw = classid 1:11 >> tc qdisc del dev ge00 handle ffff: ingress >> tc qdisc add dev ge00 handle ffff: ingress >> tc qdisc del dev ifb0 root >> tc qdisc add dev ifb0 root handle 1: htb default 12 >> tc class add dev ifb0 parent 1: classid 1:1 htb quantum 1500 rate = 15494kbit ceil 15494kbit >> tc class add dev ifb0 parent 1:1 classid 1:10 htb quantum 1500 rate = 15494kbit ceil 15494kbit prio 0 >> tc class add dev ifb0 parent 1:1 classid 1:11 htb quantum 1500 rate = 32kbit ceil 5164kbit prio 1 >> tc class add dev ifb0 parent 1:1 classid 1:12 htb quantum 1500 rate = 2582kbit ceil 15430kbit prio 2 >> tc class add dev ifb0 parent 1:1 classid 1:13 htb quantum 1500 rate = 2582kbit ceil 15430kbit prio 3 >> tc qdisc add dev ifb0 parent 1:11 handle 110: fq_codel limit 1000 ecn = quantum 500 >> tc qdisc add dev ifb0 parent 1:12 handle 120: fq_codel limit 1000 ecn = quantum 1500 >> tc qdisc add dev ifb0 parent 1:13 handle 130: fq_codel limit 1000 ecn = quantum 1500 >> tc filter add dev ifb0 parent 1:0 protocol all prio 999 u32 match ip = protocol 0 0x00 flowid 1:12 >> tc filter add dev ifb0 protocol ip parent 1:0 prio 1 u32 match ip tos = 0x00 0xfc classid 1:12 >> tc filter add dev ifb0 protocol ipv6 parent 1:0 prio 2 u32 match ip6 = priority 0x00 0xfc classid 1:12 >> tc filter add dev ifb0 protocol ip parent 1:0 prio 3 u32 match ip tos = 0x20 0xfc classid 1:13 >> tc filter add dev ifb0 protocol ipv6 parent 1:0 prio 4 u32 match ip6 = priority 0x20 0xfc classid 1:13 >> tc filter add dev ifb0 protocol ip parent 1:0 prio 5 u32 match ip tos = 0x10 0xfc classid 1:11 >> tc filter add dev ifb0 protocol ipv6 parent 1:0 prio 6 u32 match ip6 = priority 0x10 0xfc classid 1:11 >> tc filter add dev ifb0 protocol ip parent 1:0 prio 7 u32 match ip tos = 0xb8 0xfc classid 1:11 >> tc filter add dev ifb0 protocol ipv6 parent 1:0 prio 8 u32 match ip6 = priority 0xb8 0xfc classid 1:11 >> tc filter add dev ifb0 protocol ip parent 1:0 prio 9 u32 match ip tos = 0xc0 0xfc classid 1:11 >> tc filter add dev ifb0 protocol ipv6 parent 1:0 prio 10 u32 match ip6 = priority 0xc0 0xfc classid 1:11 >> tc filter add dev ifb0 protocol ip parent 1:0 prio 11 u32 match ip = tos 0xe0 0xfc classid 1:11 >> tc filter add dev ifb0 protocol ipv6 parent 1:0 prio 12 u32 match ip6 = priority 0xe0 0xfc classid 1:11 >> tc filter add dev ifb0 protocol ip parent 1:0 prio 13 u32 match ip = tos 0x90 0xfc classid 1:11 >> tc filter add dev ifb0 protocol ipv6 parent 1:0 prio 14 u32 match ip6 = priority 0x90 0xfc classid 1:11 >> tc filter add dev ifb0 parent 1:0 protocol arp prio 15 handle 1 fw = classid 1:11 >> tc filter add dev ge00 parent ffff: protocol all prio 10 u32 match = u32 0 0 flowid 1:1 action mirred egress redirect dev ifb0 >>=20 >> I notice it seem this only shows up for egress(), but looking at = simple.qos ingress() is not addend ${ADSLL} at all so that is to be = expected. There is nothing in dmesg at all. >>=20 >> So I am off to add ADSLL to ingress() as well and then test RRUL = again... >>=20 >>=20 >> Jesper please let me know if this looks reasonable, at least to my = eye it seems to fit with what "tc disc add htb help" tells me. I tried = your: >> echo "func __detect_linklayer +p" = /sys/kernel/debug/dynamic_debug/control >> but got no output even though debugs was already mounted=85 >>=20 >> Best >> Sebastian >>=20 >>>=20 >>> Now, I have been testing this using Dave's most recent cerowrt = alpha version with a 3.10.9 kernel on mips hardware, I think this kernel = should contain all htb fixes including commit 8a8e3d84b17 (net_sched: = restore "linklayer atm" handling) but am not fully sure. >>>=20 >>> It does. >>>=20 >>> `@Dave is there an easy way to find which patches you applied to the = kernels of the cerowrt (testing-)releases? >>>=20 >>> Normally I DO commit stuff that is in testing, but my big push this = time around was to get everything important into mainline 3.10, as it = will be the "stable" release for a good long time. >>>=20 >>> So I am still mostly working the x86 side at the moment. I WAS kind = of hoping that everything I just landed would make it up to 3.10. But = for your perusal: >>>=20 >>> http://snapon.lab.bufferbloat.net/~cero2/patches/3.10.9-1/ has most = of the kernel patches I used in it. 3.10.9-2 has the ipv6subtrees patch = ripped out due to another weird bug I'm looking at. (It also has support = for ipv6 nat thx to the ever prolific stephen walker heeding the call = for patches...). 100% totally untested, I have this weird bug to figure = out how to fix next: >>>=20 >>> = http://lists.alioth.debian.org/pipermail/babel-users/2013-August/001419.ht= ml >>>=20 >>> I fear it's a comparison gone south, maybe in bradley's = optimizations for not kernel trapping, don't know. >>>=20 >>> 3.10.9-2 also disables dnsmasq's dhcpv6 in favor of 6relayd. I HATE = losing the close naming integration, but, had to try this.... >>>=20 >>> If you guys want me to start committing and pushing patches again, = I'll do it, but most of that stuff will end up in 3.10.10, I think, in a = couple days. The rest might make 3.12. Pie has to survive scrutiny on = the netdev list in particular. >>>=20 >>> While I have you r attention :) I also tested 3.10.9-1's pie and it = is way better than 3.10.6-1's (RRUL ping RTTs around 110 ms instead of = 3000ms) but still worse than fq_codel (ping RTTs around 40ms with proper = atm link layer adjustments). >>>=20 >>> This is with simple.qos I imagine? Simplest should do better than = that with pie. Judging from how its estimator works I think it will do = badly with multiple queues. But testing will tell... >>>=20 >>> But, yea, this pie is actually usable, and the previous wasn't. = Thank you for looking at it! >>>=20 >>> It is different from cisco's last pie drop in that it can do ecn, = does local congestion notification, has a better use of net_random, it's = mostly KernelStyle, and I forget what else. >>>=20 >>> There is still a major rounding error in the code, and I'd like = cisco to fix the api so it uses identical syntax to codel. Right now you = specify "target 8" to get "target 7", and the "ms" is implied. target 5 = becomes target 3. The default target is a whopping 20 (rounded to 19), = which is in part where your 70+ms of extra delay came from. >>>=20 >>> Multiple parties have the delusion that 20ms is "good enough". >>>=20 >>> Part of the remaining delay may also be rounding error. Cisco uses = kernels with HZ=3D1000, cero uses HZ=3D250..... >>>=20 >>> Anyway, to get more comparable tests... you can fiddle with the two = $QDISC lines in simple*.qos to add a target 8 to get closer to a codel = 5ms config, but that would break a codel config which treats target 8 as = target 8us. >>>=20 >>> I MIGHT, if I get energetic enough, fix the API, the time = accounting, and a few other things in pie, the problem is, that = ns2_codel seems still more effective on most workloads and *fq_codel = smokes absolutely everything. There are a few places where pie is a win = over straight codel, notably on packet floods. And it may well be easier = to retrofit into existing hardware fast path designs. >>>=20 >>> I worry about interactions between pie and other stuff. It seems = inevitable at this point that some form of pie will be widely deployed, = and I simply haven't tried enough traffic types and RTTs to draw a firm = conclusion, period. Long RTTs are the last big place where codel and pie = and fq_codel have to be seriously tested. >>>=20 >>> ns2_codel is looking pretty good now, at the shorter RTTs I've = tried. A big problem I have is getting decent long RTT emulation out of = netem (some preliminary code is up at github) >>>=20 >>> ... and getting cero stable enough for others to actually use - next = up is fixing the userspace problems. >>>=20 >>> ... and trying to make a small dent in the wifi problem along the = way (couple commits coming up) >>>=20 >>> ... and find funding to get through the winter. >>>=20 >>> There's probably a few other things that are on that list but I = forget. Oh, yea, since the aqm wg was voted on to be formed, I decided I = could quit smoking. >>>=20 >>> While I am not able to build kernels, it seems that I am able to = quickly test whether link layer adjustments work or not. SO aim happy to = help where I can :) >>>=20 >>> Give pie target 8 and target 5 a shot, please? ns2_codel target 3ms = and target 7ms, too. fq_codel, same.... >>>=20 >>> tc -s qdisc show dev ge00 >>> tc -s qdisc show dev ifb0 >>>=20 >>> would be useful info to have in general after each test. >>>=20 >>> TIA. >>>=20 >>> There are also things like tcp_upload and tcp_download and = tcp_bidirectional that are useful tests in the rrul suite. >>>=20 >>> Thank you for your efforts on these early alpha releases. I hope = things will stablize more soon, and I'll fold your aqm stuff into my = next attempt this weekend. >>>=20 >>> This is some of the stuff I know that needs fixing in userspace: >>>=20 >>> * TODO readlink not found >>> * TODO netdev user missing >>> * TODO Wed Dec 5 17:14:46 2012 authpriv.error dnsmasq: found = already running DHCP-server on interface 'se00' refusing to start, use = 'option force 1' to override >>> * TODO [ 18.480468] Mirror/redirect action on >>> [ 18.539062] Failed to load ipt action >>> * upload and download are reversed in aqm >>> * BCP38 >>> * Squash CS values >>> * Replace ntp >>> * Make ahcp client mode >>> * Drop more privs for polipo >>> * upnp >>> * priv separation >>> * Review FW rules >>> * dhcpv6 support >>> * uci-defaults/make-cert.sh uses a bad path for px5g >>> * Doesn't configure the web browser either >>>=20 >>>=20 >>>=20 >>>=20 >>> Best >>> Sebastian >>>=20 >>>=20 >>>=20 >>>=20 >>> -- >>> Dave T=E4ht >>>=20 >>> Fixing bufferbloat with cerowrt: = http://www.teklibre.com/cerowrt/subscribe.html >>=20 >>=20 >>=20 >>=20 >> -- >> Dave T=E4ht >>=20 >> Fixing bufferbloat with cerowrt: = http://www.teklibre.com/cerowrt/subscribe.html >=20 >=20 >=20 >=20 > --=20 > Dave T=E4ht >=20 > Fixing bufferbloat with cerowrt: = http://www.teklibre.com/cerowrt/subscribe.html