[Cerowrt-devel] Proper AQM settings for my connection?

Dave Taht dave.taht at gmail.com
Sat Dec 21 00:16:34 EST 2013

Netanalyzr is inaccurate. It pushes out a udp stream for not long
enough fpr codel to react, thus giving you an over-estimate, and
furthermore doesn't detect the presence of flow queuing on the link by
sending a secondary flow. This latter problem in netanalyzer is
starting to bug me. They've known they don't detect SFQ, SQF, or
fq_codel or drr for a long time now, these packet schedulers are
deployed at the very least at FT and free.fr and probably quite a few
places more, and detecting it is straightforward.

Netanalyzr + a ping on the side is all that is needed to see
difference between bloat, aqm, and packet scheduling.

 The rrul test is even better.

I would be interested in your pie results on the link...

netanalyzer + a ping -c 60 somewhere in both cases...

however...  there WAS a lot of churn in the AQM code these past few
months, so it is possible you have a busted version of the aqm scripts
as well. a sample of your

tc -s qdisc show dev ge00

would be helpful. As rich says, 3.10.24-5 is pretty good at this
point, and a large number of people have installed it, with only a few
problems (We have a kernel issue that rose it's ugly head again
(instruction traps), and we are discussing improving the web interface

So upgrade first.

On Fri, Dec 20, 2013 at 9:01 PM, Rich Brown <richb.hanover at gmail.com> wrote:
> On Dec 20, 2013, at 11:32 PM, Hector Ordorica <hechacker1 at gmail.com> wrote:
>> I'm running 3.10.13-2 on a WNDR3800, and have used the suggested
>> settings from the latest draft:
>> http://www.bufferbloat.net/projects/cerowrt/wiki/Setting_up_AQM_for_CeroWrt_310
>> I have a 30Mb down / 5Mb upload cable connection.
>> With fq_codel, even undershooting network upload bandwidth by more
>> than 95%, I'm seeing 500ms excessive upload buffering warnings from
>> netalyzr. Download is ok at 130ms. I was previously on a 3.8 release
>> and the same was true.
> I have seen the same thing, although with different CeroWrt firmware. Netalyzr was reporting
>> 500 msec buffering in both directions.
> However, I was simultaneously running a ping to Google during that Netalyzr run, and the
> ping times started at ~55 msec before I started Netalyzr, and occasionally they would bump
> up to 70 or 80 msec, but never the long times that Netzlyzr reported...
> I also reported this to the Netalyzr mailing list and they didn’t seem surprised. I’m not sure how to interpret this.
>> With pie (and default settings), the buffer warnings go away:
>> http://n2.netalyzr.icsi.berkeley.edu/summary/id=43ca208a-32182-9424fd6e-5c5f-42d7-a9ea
>> And the connection performs very well while torrenting and gaming.
>> Should I try new code? Or can I tweak some variables and/or delay
>> options in scripts for codel?
> A couple thoughts:
> - There have been a bunch of changes between 3.10.13-2 and the current version (3.10.24-5, which seems pretty stable). You might try upgrading. (See the “Rough Notes” at the bottom of http://www.bufferbloat.net/projects/cerowrt/wiki/CeroWrt_310_Release_Notes for the progression of changes).
> - Have you tried a more aggressive decrease to the link speeds on the AQM page (say, 85% instead of 95%)?
> - Can we get more corroboration from the list about the behavior of Netalyzer?
> Rich
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Dave Täht

Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html

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