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

[Aaron Wood]

I dug out the info from the friend of mine doing this testing, and he was
about to get the dslreports_8dn test to deliver ~800Mbps from his server,
but only ~122Mbps from flent-freemont.bufferbloat.net.  Which is awfully
suspicious that this is a setup issue with the node in fremont.

On Thu, Sep 21, 2017 at 8:16 AM, Aaron Wood <woody77 at gmail.com> wrote:

> The friend of mine that I've been working with brought up a cloud node
> somewhere with ubuntu and netperf on it, and from another location
> (business internet) able to consistently get better throughput from his
> cloud node setup than from the flent-fremont node.  We're starting to think
> that it's something about that node in particular.  It seems to have a
> 125Mbps cap (so I guess about a 140-150Mbps line-rate cap?).
>
> What kind of node is it running on?
>
> On Thu, Sep 21, 2017 at 8:13 AM, Aaron Wood <woody77 at gmail.com> wrote:
>
>> 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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