On Tue, Feb 25, 2014 at 6:14 AM, Oliver Niesner <oliver.niesner@gmail.com> wrote:

Hi list,

I use cerowrt (3.10.24-8) direct behind my main dsl Router.
SQM is set and performance is good.
When i used Netalyzr from my smartphone i've got good results.

> Network buffer measurements (?): Uplink 96 ms, Downlink is good

But when i use my notebook i get this:

> Network buffer measurements (?): Uplink 1200 ms, Downlink is good

I tried even wired connection and set ring buffer rx/tx with ethtool to 64, but
only minimal change in uplink buffer (1100ms).

Has anyone an idea, what i can try to get better uplink performance?

Netalyzr uses a UDP based test for "filling the buffers"; it is not responsive to drops/marks at all, the way a TCP test would be.

So if you run it, the flows it generates are unresponsive, and indicate the true size of the buffers at the bottleneck link, even though any normal TCP would long since have responded and nothing like that amount of buffering would have taken place. Furthermore, the flow queuing of fq_codel isolates those flows from other flows, and therefore you do not get the bad latency you would otherwise get on those flows.

In short, (particularly since fq_codel is deployed in quantity millions by a few ISP's already; it is no longer a fluke to find it only in hacker's hands), Nick Weaver needs to improve netalyzr to detect flow queuing algorithms and make some sense out of the situation. It would be great to monitor the spread of these algorithms around the Internet over the coming years.

So it is arguably a "bug" in netalyzr. It is certainly extremely misleading.

Nick?

- Jim

Regards,

Oliver

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