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

[Aaron Wood <woody77@gmail.com>]

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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@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@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@lists.bufferbloat.net] *On Behalf Of
>> *Aaron Wood
>> *Sent:* Tuesday, August 29, 2017 11:16 PM
>> *To:* bloat <bloat@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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