>  Basically, the problem is the way netperf determines its data output 
> intervals in demo mode:

Ahah! That was the explanation, but I wasn't (yet) smart enough to comprehend 
it. [To further test out my understanding... If netperf were to use a smaller 
"data output interval" when it's transmitting, it would create more frequent 
updates and the granularity would be higher...]

But I'm not sure that fully explains it unless netperf uses a (very) different 
data output interval for receiving... The download chart has hundreds of 
points, while the ratio between my download and upload is about 10:1 (7mbps vs 
768kbps) so I'd expect the upload chart to have something like dozens of 

Wait... maybe the chart really does have more points: each of the four plots 
above might have many inflection points but since fq_codel controls their rates 
so carefully, there's little change to their values, thus no obvious change to 
the charted values... And yes - turning off SQM (see image below) shows many 
more data points for those upload plots. 

But are there enough points? In the download chart, I count around 30 samples 
for one plot in a 10-second period. So that's 3 per second. With an average 
data rate of 1.6mbps, it looks like 500 kbits/sample (a nice round number, 
arrived at with a SWAG - scientific wild ass guess.)

If the upload has the same data output interval, those upload streams 
(averaging 0.11 mbps) would need about 4.5 seconds to transmit that 500kbits. 
And if you squint at the plot below, and take into account the enormous SWAG in 
the previous paragraph, it looks OK.

All's right with the world. (But only after I remember to turn SQM back on...) 

<img width="840" alt="image" 

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