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From: "Toke Høiland-Jørgensen" <toke@toke.dk>
To: Mikael Abrahamsson <swmike@swm.pp.se>
Cc: codel@lists.bufferbloat.net, cerowrt-devel@lists.bufferbloat.net
Subject: Re: [Codel] happy 4th!
Date: Tue, 09 Jul 2013 09:57:20 +0200	[thread overview]
Message-ID: <87obacw4gv.fsf@toke.dk> (raw)
In-Reply-To: <alpine.DEB.2.00.1307090749480.8891@uplift.swm.pp.se> (Mikael Abrahamsson's message of "Tue, 9 Jul 2013 08:04:39 +0200 (CEST)")

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Mikael Abrahamsson <swmike@swm.pp.se> writes:

> For me, it shows that FQ_CODEL indeed affects TCP performance
> negatively for long links, however it looks like the impact is only
> about 20-30%.

As far as I can tell, fq_codel's throughput is about 10% lower on
100mbit in one direction, while being higher in the other. For 10mbit
fq_codel shows higher throughput throughout?

> What's stranger is that latency only goes up to around 230ms from its
> 200ms "floor" with FIFO, I had expected a bigger increase in buffering
> with FIFO. Have you done any TCP tuning?

Not apart from what's in mainline (3.9.9 kernel). The latency-inducing
box is after the bottleneck, though, so perhaps it has something to do
with that? Some interaction between netem and the ethernet link?

> Would it be easy for you to do tests with the streams that "loads up
> the link" being 200ms RTT, and the realtime flows only having 30-40ms
> RTT, simulating downloads from a high RTT server and doing interactive
> things to a more local web server.

Not on my current setup, sorry. Also, I only did these tests because I
happened to be at my lab anyway yesterday. Not going back again for a
while, so further tests are out for the time being, I'm afraid...

-Toke

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  parent reply	other threads:[~2013-07-09  7:57 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAA93jw7WPdxKwGGvQoSEfmDN3ey9j7+BNT5yohB6XUyCqbQRtQ@mail.gmail.com>
     [not found] ` <alpine.DEB.2.00.1307040751130.10894@uplift.swm.pp.se>
     [not found]   ` <1373223178.486913695@apps.rackspace.com>
     [not found]     ` <alpine.DEB.2.00.1307080211340.10894@uplift.swm.pp.se>
     [not found]       ` <871u79x9kb.fsf@toke.dk>
     [not found]         ` <alpine.DEB.2.00.1307090749480.8891@uplift.swm.pp.se>
2013-07-09  6:32           ` [Codel] [Cerowrt-devel] " Dave Taht
2013-07-09  7:30             ` Andrew McGregor
2013-07-09 13:09             ` Eric Dumazet
2013-07-09  7:57           ` Toke Høiland-Jørgensen [this message]
2013-07-09 12:56             ` [Codel] " Eric Dumazet
2013-07-09 13:13               ` Toke Høiland-Jørgensen
2013-07-09 13:23                 ` Eric Dumazet
2013-07-09 13:25                   ` Toke Høiland-Jørgensen
2013-07-09 13:36                 ` Eric Dumazet
2013-07-09 13:45                   ` Toke Høiland-Jørgensen
2013-07-09 13:49                     ` Eric Dumazet
2013-07-09 13:53                       ` Toke Høiland-Jørgensen
2013-07-09 14:07                         ` Eric Dumazet

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