[Bloat] how to fix modem buffer bloat?

Naeem Khademi naeem.khademi at gmail.com
Tue Aug 27 09:31:39 EDT 2013


I would like to hear a bit of more elaboration on why the use of
fq_codel on wlanX interface is "premature". from what I have grasped
so far, I can think of A) frame aggregation and TXOPs in 802.11n, B)
anything on the downlink path that coexists with uplink traffic on
802.11g/n. any thoughts on other major issues?

excluding .11n-specific issues, what else could be problematic for
fq_codel for a 802.11g scenario with predominantly downlink traffic
and minstrel RA?

Regards,
Naeem

On Mon, Aug 26, 2013 at 9:28 PM, Dave Taht <dave.taht at gmail.com> wrote:
> The advantage of cerowrt is that it runs about 3-4 months ahead of openwrt
> on improvements to the bloat problem, and fixing bugs.
>
> The disadvantage is that it runs about 3-4 months ahead of openwrt on having
> new bugs.
>
> Example: We just finished (with the aid of multiple parties ) finally fixing
> a problem in HTB's atm DSL compensation that has existed for a year (and
> probably several years before that), and I think the final set of fixes will
> land in Linux 3.10.10 or .11 soon.
>
> Right now it's very possible to merely layer two components of cero on top
> of openwrt to get most of the benefit of the current work. (the aqm-scripts
> and gui, and if you are daring, a couple patches to codel and fq_codel)
>
> Sadly, I wouldn't recomend the current dev builds of cero for day-to-day use
> at this point, although I hope to get to a new stable release by the end of
> september. There's a ton of outstanding bugs left to fix.
>
> While openwrt runs fq_codel by default on all interfaces, it's mildly
> premature to be doing so on the wifi front. Work is in progress. However in
> the general case, at the moment the principal use for fq_codel in a home
> router is on the gateway to the internet - the fq_codel QoS system in
> openwrt and dd-wrt works extremely well (with the exception of ipv6 native).
> I believe the package in cerowrt is better in most respects (notably on
> ipv6), but limited in others. Gargoyle is using a prior effort (improved sfq
> + an automatic rate measurement system called ACC). There are other options
> like using small atom boxes, ipfire, and several commercial products....
>
> The stable (feburary) release of cero is pretty usable, but lacks the
> modernized aqm scripts, the htb fix, a bunch of ipv6 fixes, etc, etc.
>
> I wish I could give firm advice, but we're kind of in the middle of a ton of
> stuff right now, all I can do is encourage you to leap in, fix things for
> yourself, and help out where you can.
>
>
>
> On Mon, Aug 26, 2013 at 11:53 AM, Collin Anderson <cmawebsite at gmail.com>
> wrote:
>>
>> Hi All,
>>
>> > Any recommendations for solving the bufferbloat on my Comcast SMC cable
>> > modem?
>>
>> Looking at it more, a workaround is probably all I can hope for at
>> this point. I first started keeping a ping session open back in 2008
>> to debug the internet, and I see bufferbloat almost every day at home
>> and at work. Anything to avoid the symptoms sounds great.
>>
>> I want something reliable and have minimal configuration. I'm thinking
>> about buying a WNDR3800 and installing CeroWRT, or is there better
>> recommended hardware?
>>
>> Also, isn't fq_codel "on by default" [1] in OpenWRT? If so, what's the
>> advantage of CeroWRT?
>>
>> Thanks,
>> Collin
>>
>> [1] http://www.ietf.org/proceedings/87/slides/slides-87-aqm-6.pdf
>> _______________________________________________
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>> Bloat at lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/bloat
>
>
>
>
> --
> Dave Täht
>
> Fixing bufferbloat with cerowrt:
> http://www.teklibre.com/cerowrt/subscribe.html
>
> _______________________________________________
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> Bloat at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/bloat
>



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