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From: d@taht.net (Dave Täht)
To: Juliusz Chroboczek <jch@pps.jussieu.fr>
Cc: bloat@lists.bufferbloat.net
Subject: Re: [Bloat] About Stochastic Fair Blue (SFB)
Date: Fri, 04 Feb 2011 08:12:53 -0700	[thread overview]
Message-ID: <87zkqbn896.fsf@cruithne.co.teklibre.org> (raw)
In-Reply-To: <87k4hgdte9.fsf@trurl.pps.jussieu.fr> (Juliusz Chroboczek's message of "Fri, 04 Feb 2011 10:46:22 +0100")


Juliusz Chroboczek <jch@pps.jussieu.fr> writes:


> Hi again,

> One AQM that attempts both is Stochastic Fair a stochastically-fair
> variant of BLUE [1].  In addition to reducing buffer size and enforcing
> rough inter-flow fairness, SFB will reliably detect unresponsive flows
> and rate-limit them.
>
> In order to experiment with SFB, I've implemented it for Linux a couple
> of years ago [2].  Unfortunately, I've given up for now on trying to get
> it into the mainline kernel, and I'm not sure I want to try again [3].

I had incorporated juliusz's patches to the tc utility here in my git
repo here a few weeks back.

https://github.com/dtaht/iproute2bufferbloat

(I would be very interested in accumulating the other patches to tc for
the other new AQMs, too, if anyone knows what or where they are)

So a patched tc + SFB modules gives you a new AQM to work with.

The SFB code seems to compile as modules and insert into modern kernels
just fine. I've built it on arm, x86_64, and x86, with mips on my list
soon.

However, the usage is a little vague. Could you make some suggestions as
to a "shaping stack" to fiddle with, for example, a wireless environment
or home gateway scenario? [1]

Also, would you mind if I also put the SFB code into git somewhere 
on github? It could use a few minor tweaks (make install). 

Things I like about SFB

1) You can hash against multiple combinations of things. For example, in
the home gateway scenario, you could hash against IP addresses only, not
IP/port numbers - to give a per-device level of fairness. 

2) It has a brilliant idea in the bloom filter - it looks like that
concept can scale..

3) It does packet marking... (So has to be used in combination with
something else)

4) it works with ipv6.

Things that I don't "get" about SFB.

1) I don't understand how the penalty box concept works.

2) I don't understand how it would interact with shaping above and below it[2]


-- 
Dave Taht
http://nex-6.taht.net

[1] and in my case my driver set is so bloated that traffic shaping at
the moment does little good - but I'm getting there.

[2] Yes, I've read the paper. And the code. Twice.

  parent reply	other threads:[~2011-02-04 15:13 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-04  9:46 Juliusz Chroboczek
2011-02-04 13:56 ` Jim Gettys
2011-02-04 17:33   ` [Bloat] Buffer bloat at the sender [was: About Stochastic Fair Blue (SFB)] Juliusz Chroboczek
2011-02-04 18:24     ` Jim Gettys
2011-02-04 18:58       ` [Bloat] Buffer bloat at the sender Juliusz Chroboczek
2011-02-04 19:26         ` Dave Täht
2011-02-04 18:43     ` Dave Täht
2011-02-04 18:56       ` Juliusz Chroboczek
2011-02-04 19:58         ` Dave Täht
2011-02-04 20:14           ` Juliusz Chroboczek
2011-02-04 15:12 ` Dave Täht [this message]
2011-02-04 17:41   ` [Bloat] About Stochastic Fair Blue (SFB) Juliusz Chroboczek
2011-02-04 18:54     ` Dave Täht
2011-02-04 19:02       ` Juliusz Chroboczek

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