[Cerowrt-devel] Comcast Uplink Buffers

William Katsak wkatsak at gmail.com
Thu Mar 5 10:49:13 EST 2015


Thanks for the reply. I should have made it clearer that I am not 
running this on a Netgear 3800, I am running the sqm system on an Atom 
D510 box at 1.66 GHz (two cores + hyperthreads) with 2 GB RAM and good 
Intel NICs. While running the rrul, the CPU is barely breaking a sweat.

The OS is Ubuntu server and I've made a nice wrapper to run simple.qos 
via the if-pre-up/post-down hooks.

Can you suggest any tweaks to the settings that would better take 
advantage of the extra CPU that I have?


On 03/05/2015 10:43 AM, Dave Taht wrote:
> well, cerowrt's inbound shaper runs out of cpu at +60mbits. That is
> possibly part of your problem.
> the peaks you are seeing are not bad - but to me, probably indicative
> of running out of cpu, which will among other things, drop packets
> burstily.
> As comcast has rolled out 100mbit+ service in a ton of places
> (including my home), we really, really, really need to find a way to
> do better rate shaping at higher speeds (or develop a faster policer)
> on some successor hardware.
> If you turn off inbound shaping (0 for that parameter) my measurements
> typically show over 600ms of latency on inbound on comcast at 100mbit
> down, but at least, doing the tcp_upload tests, we can hold the upload
> more under control. It is a totally unsatisfactory thing to have
> downloads got so much out of control, it really messes up other
> things, inside of a few seconds, on big downloads, but at this point I
> have to recommend turning off inbound shaping and just living with it.
> Very high on my list now is finally writing (or tom sawyering someone
> into writing!) "bobbie - the kinder, gentler policer" in the hope that
> that could actually run faster and better than shaping does on this
> low end hardware.
> On Thu, Mar 5, 2015 at 7:35 AM, William Katsak <wkatsak at gmail.com> wrote:
>> Hello all,
>> I just moved and had to switch my ISP from Optimum (Cablevision) to Comcast
>> (100/10 link).
>> I am running my own port of simple.qos over to Debian/Ubuntu, and it worked
>> fine on Cablevision (I basically use scripts in if-pre-up.d and
>> if-post-down.d to set the variables set up/tear down simple.qos).
>> However, since I moved over to Comcast, I am seeing something like 600 ms of
>> uplink buffering according to Netlyzer. Also, the Internet browsing "feels"
>> slow when Netflix is in use elsewhere in the apartment (like before I knew
>> anything about bufferbloat).
>> My config looks like this:
>> UPLINK=7500
>> DOWNLINK=85000
>> QDISC=fq_codel
>> LLAM="tc_stab"
>> LINKLAYER="none"
>> STAB_MTU=2047
>> LIMIT=1001   # sane global default for *LIMIT for fq_codel on a small memory
>> device
>> ITARGET="auto"
>> ETARGET="auto"
>> TC=`which tc`
>> #TC="sqm_logger tc"# this redirects all tc calls into the log
>> IP=$( which ip )
>> INSMOD=`which modprobe`
>> TARGET="5ms"
>> IPT_MASK="0xff"
>> IPT_MASK_STRING="/${IPT_MASK}"     # for set-mark
>> I've also attached the output of a run of rrul against
>> netperf.bufferbloat.net.
>> Any insight?
>> Thanks,
>> Bill
>> --
>> ****************************************
>> William Katsak <wkatsak at gmail.com>
>> ****************************************
>> _______________________________________________
>> Cerowrt-devel mailing list
>> Cerowrt-devel at lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/cerowrt-devel

William Katsak <wkatsak at gmail.com>

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