[Bloat] different speeds on different ports? (benchmarking fun)

[Aaron Wood]

I'd wondered about single vs. multiple, but I'm getting pretty consistent
speeds from the flent-fremont node irrespective of the number of streams
that I use (1, 4, 12, etc).

On Thu, Sep 21, 2017 at 7:50 AM, Colin Dearborn <Colin.Dearborn at sjrb.ca>
wrote:

> This is my guess.
>
> DSL reports uses many streams from different servers to achieve these
> speeds.
>
> I’m assuming flent is a single stream, so you’re at the mercy of TCP
> receive windows and latency limiting how fast you can go on that single
> stream.
>
>
>
> *From:* Bloat [mailto:bloat-bounces at lists.bufferbloat.net] *On Behalf Of *Aaron
> Wood
> *Sent:* Tuesday, August 29, 2017 11:16 PM
> *To:* bloat <bloat at lists.bufferbloat.net>
> *Subject:* [Bloat] different speeds on different ports? (benchmarking fun)
>
>
>
> I don't have a full writeup yet, but wanted to ask if people on here have
> run into this.
>
>
>
> I'm seeing a disparity between flent and the dslreports speed tests.  On
> my connection at home (Comcast 150/12), I figured it was something related
> to the test implementations, but minor.  But on a connect at a friend with
> business-class Comcast (300/12), we're seeing a huge difference.  Flent
> can't seem to achieve more than 120Mbps, often with an early, couple-second
> hump at a much higher speed.  But dslreports' speed tests gets the full
> 300Mbps.
>
>
>
> In looking closer at my connection, with sqm (cake) turned off, I'm seeing
> ~180Mbps download with 500ms of bufferbloat when I use the dslreports test (
> http://www.dslreports.com/speedtest/20805152).
>
>
>
> Yet flent can't come close to that, even with the tcp_12down test:
>
>
> ​
>
> The current hypothesis that we have is that this is due to either traffic
> class, or the ports that traffic are running on.  I've ruled out the ping
> streams, as a parallel set of netperf tcp_maerts downloads has the same
> 120Mbps roof.
>
>
>
> It would be interesting if we could run some netperf tests using port
> 80/443 for the listening socket for the data connection (although if doing
> deep-packet inspection, we might need to use an actual HTTP transfer).
>
>
>
> -Aaron
>
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