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Re: Throughput riddle

On Sun, 20 Mar 2016 09:31:24 -0700
David Christensen <dpchrist@holgerdanske.com> wrote:


> But, I still recommend Category 5E cables.
> >> It's not clear if you are doing an apples-to-apples comparison.  Perhaps
> >> iperf isn't measuring what you think it is.
> >
> > That's exactly what I'm asking: what is iperf measuring, and why is it
> > so much lower than the speedtest throughput? My understanding is that
> > it simply measures straight-up TCP (or UPD, if desired) throughput.
> > Even allowing for protocol overhead at the various network stack
> > layers, the deviation shouldn't be that great.
> Perhaps you can find information on the project site (?):
>      https://github.com/esnet/iperf


> Assuming you've looked for error/ warning messages everywhere and 
> haven't seen anything obvious, the next step would seem to be enabling 
> or adding verbosity/ logging/ debugging/ etc., starting with iperf on 
> one end and ending with iperf on the other end.

FWIW, I'm getting these:

Tx excessive retries:392922  Invalid misc:5439

[Rx invalids are all 0]

Which seems to mean that there are some problems with the connection.
But I don't have any sense of what's normal, particularly with
wireless, or how bad this is (obviously, I'd have to keep track of the
retries / invalids per time / data transmitted).

AFAICT, iperf has no verbosity / logging / debugging settings.



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