Re: [Make-wifi-fast] Fun with DSCP and latency

[Bob McMahon <bob.mcmahon@broadcom.com>]

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I can't speak to these chips or drivers but we have the ability to fault
isolate latency via much more advanced network telemetry.

This type of testing seems likely to be conflating buffer bloat with
latency. They're two different phenomena.

iperf 2.1.0 <https://sourceforge.net/projects/iperf2/> has a
--near-congestion option to help test latency rather than bloat. It's not
perfect but is reproducible for controlled networks.

Also, probably a good idea to synchronize clocks.  NTP stratum-1 servers
can be built with a raspberry pi and a GPS hat. One can yse PTP to
distribute.

The average crystal ends up being about as accurate as a mechanical watch
<https://tinyurl.com/y3jbwgmy>
DIY Raspberry Pi GPS stratum 1 clock
<https://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html>

Bob

On Thu, Jan 21, 2021 at 1:09 PM Tim Higgins via Make-wifi-fast <
make-wifi-fast@lists.bufferbloat.net> wrote:

> Hi all,
>
> I've found unexpected behavior running simultaneous ping and TCP/IP tests
> using multiple AX200
> based Linux STAs and different iperf3 --dscp values for each STApal.
>
> Details are in the document linked below. I'd appreciate it if you could
> read and comment.
>
> _
> https://docs.google.com/document/d/1XB-DaqBzDDprdb-SorWK5sSwtzMhrOSYXiDOrGU_fq4/edit?usp=sharing_
> <
> https://docs.google.com/document/d/1XB-DaqBzDDprdb-SorWK5sSwtzMhrOSYXiDOrGU_fq4/edit?usp=sharing
> >
>
> Thanks
> ===========
> Tim Higgins
>
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> Make-wifi-fast mailing list
> Make-wifi-fast@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/make-wifi-fast

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