SQM high latency

Installing and Using OpenWrt
81

@jow is there a way to disable GRO in the driver without using ethtool?

82

All the information I've read points to ethtool.

1 Like
83

OP solved! Replacing the Thomson DCM475 modem with a Hitron CDA-RES did it. Piece of cake SQM on an Archer C7 led to A+ bufferbloat at full 130Mbps. The Thomson modem simply had an oscillating bufferbloat that couldn't be controlled by SQM, whereas the Hitron has a constant 500ms bufferbloat that can be smoothed out. :+1:

84

@Sunspark; Advanced option string to pass to the egress queueing disciplines; no error checking, use very carefully (specify overhead NN) e.g. overhead 28

My Config:

config queue 'eth1'
option interface 'eth1'
option ingress_ecn 'ECN'
option egress_ecn 'ECN'
option itarget 'auto'
option etarget 'auto'
option linklayer 'none'
option debug_logging '0'
option verbosity '5'
option qdisc 'cake'
option qdisc_advanced '1'
option squash_dscp '1'
option squash_ingress '1'
option qdisc_really_really_advanced '1'
option iqdisc_opts 'overhead 35 dual-dsthost nat mpu 64'
option eqdisc_opts 'overhead 28 dual-srchost nat mpu 64'
option enabled '1'
option script 'piece_of_cake.qos'
option download '60000'
option upload '4000'

85

For a cable link these look suspicious, I would believe that setting both up- and downstream overhead to 18 would be theoretically more correct for a cable link. But if you empirically found your values, please ignore my theoretical concerns...

Best Regards

86

I'm all over the map here and although things mostly work, i'm ready to chunk this wndr3800ch and buy a newer router. It's been a test router till lede gets sorted but it's acting weird. Upgrading to the newer 4.4.61 has seemingly corrected some odd behavior in sqm but other bugs with redirects/port forwading I've posted are there. It's hard to get a firm conclusion without something stable. I'm gonna try fq_codel/simple.qos for a week on this new kernel and check for differences. Cake is too inconsistent with ANY setting applied.

87

Well, sad to hear that. I run a wndr3700v2 on a 50/10 link and cake works pretty well for me, but I do not play on-line games, twitch, stream or even bit-torrent, so my traffic patterns are probably pretty boring and well behaved....

88

My main issues is the latency spikes well over 30ms. Charter has unusually fluctuations in rtt and jitter even considering the routes. Here are some mtr runs

Pearl River,LA <----->Google
My traceroute [v0.85]
LEDE (0.0.0.0) Fri Apr 21 15:19:02 2017
Keys: Help Display mode Restart statistics Order of fields quit
Packets Pings
Host Loss% Snt Last Avg Best Wrst StDev

  1. ???
  2. dtr03slidla-tge-0-1-0-1.slid.la. 0.0% 16 11.0 13.7 10.0 21.0 3.8
  3. 96-34-88-16.static.unas.la.chart 0.0% 16 23.9 15.9 11.3 26.4 4.1
  4. bbr02slidla-bue-1.slid.la.charte 0.0% 16 11.8 15.1 10.5 24.4 3.6
  5. bbr01sgnwmi-tge-0-2-0-10.sgnw.mi 0.0% 16 26.3 28.7 25.6 34.1 2.4
  6. prr01snjsca-tge-0-0-0-1.snjs.ca. 0.0% 16 29.7 30.0 26.7 51.8 5.9
  7. 72.14.220.17 0.0% 15 25.2 28.9 25.2 35.8 3.4
  8. 72.14.239.100 0.0% 15 27.4 27.5 24.7 34.4 2.7
  9. 72.14.233.199 0.0% 15 27.3 35.1 25.8 87.8 17.6
  10. 216.239.40.131 0.0% 15 40.9 45.0 39.4 75.3 9.0
  11. 216.239.48.7 0.0% 15 55.7 48.3 42.4 75.3 9.6
  12. 216.239.49.180 0.0% 15 39.3 42.3 39.3 50.0 3.2
  13. 108.170.246.1 0.0% 15 40.9 42.1 38.4 48.7 3.1
  14. 216.239.54.111 0.0% 15 39.7 41.6 39.1 55.1 3.9
  15. iad30s07-in-f14.1e100.net 0.0% 15 42.2 43.7 41.3 48.7 1.7

Pearl River,LA<----->Nola.com
My traceroute [v0.85]
LEDE (0.0.0.0) Fri Apr 21 15:21:48 2017
Keys: Help Display mode Restart statistics Order of fields quit
Packets Pings
Host Loss% Snt Last Avg Best Wrst StDev

  1. ???
  2. dtr03slidla-tge-0-1-0-1.slid.la. 0.0% 63 21.9 12.8 8.7 29.6 4.3
  3. 96-34-88-16.static.unas.la.chart 0.0% 62 13.1 15.0 10.2 43.1 5.2
  4. lag-102.bear1.Houston1.Level3.ne 0.0% 62 51.2 22.8 16.9 52.8 8.0
  5. ae-1-3500.ear1.Washington111.Lev 4.8% 62 43.0 48.7 43.0 151.0 14.1
  6. DYNAMIC-NET.ear1.Washington111.L 0.0% 62 44.4 46.6 42.2 81.2 6.5
  7. redirector2.dynect.net 0.0% 62 43.9 46.0 43.1 62.2 3.8

Peal River,LA<----->www.uno.edu
My traceroute [v0.85]
LEDE (0.0.0.0) Fri Apr 21 15:24:25 2017
Keys: Help Display mode Restart statistics Order of fields quit
Packets Pings
Host Loss% Snt Last Avg Best Wrst StDev

  1. ???
  2. dtr03slidla-tge-0-1-0-1.slid.la. 0.0% 24 17.5 11.8 8.4 20.0 2.7
  3. 96-34-88-16.static.unas.la.chart 0.0% 24 24.1 15.8 11.4 29.9 4.2
  4. bbr01olvemo-tge-0-1-0-6.olve.mo. 0.0% 24 24.7 26.8 23.8 38.9 3.1
  5. prr02dllstx-bue-2.dlls.tx.charte 0.0% 24 25.5 26.0 22.9 35.4 3.2
  6. 96-34-149-54.static.unas.mo.char 0.0% 24 22.9 37.4 22.9 83.3 16.9
  7. 64.57.21.66 0.0% 24 46.4 35.4 32.3 46.4 3.0
  8. ???
89

I will say both FQ_codel/Cake have alleviated close to 95% of my bufferbloat both on ethernet connections and 5ghz band. 2.4ghz is borderline saturation so depending on weather, time of day, etc it's still very nice. Gaming servers and Voip have been my main hotpoints and taking into consideration the other "end" is not well configured, too many variables come into play. I need to contruct a test lab of own to show conclusive lan results vs wan. The Xbox One is not the greatest design from Microsoft. My quest for the lowest bufferbloat and rtt figures continues...

I do have one burning question, would 2 routers, 1 acting as the edge router with sqm, and a switch/router to the lan with sqm make any difference in reducing bloat? My theory is the extra processing power may help, but also induce latency from having the extra routing maybe? check out this video https://youtu.be/T5BHDbAgdng

2 Likes
90

So I have 2 Netgear R7000's laying around. I installed the latest lede on one acting as a gateway, and the other running stock firmware. Wireless is definitely the culprit of my latency spikes. Any wifi activity judo chops my connection with spikes. WIthout wifi active everything is smooth as butter. Arrgggg! My little wndr3800ch is still fine so I'll keep it as a spare. Bufferbloat is still good with this setup. For the time being, I'll consider it done.

91

I'm back to using my WNDR3800CH for my main router for WAN/wired connections. My TP-Link Archer C7 v4 with stock firmware. adjusting the buffers to my calculated BDP, mem values, and ethtool has really improving latency.

92

so anyone able to fix this issue? i have this issue with R8000

1 Like
93

I'm having issues with SQM high latency as well. can you give me some details or look at my history to see whether this applies to me as well?