[Cerowrt-devel] [Codel] [Bloat] Latest codel, fq_codel, and pie sim study from cablelabs now available

Jesper Dangaard Brouer brouer at redhat.com
Tue May 14 08:12:15 EDT 2013

On Mon, 13 May 2013 22:26:04 -0400
Dan Siemon <dan at coverfire.com> wrote:

> On Thu, 2013-05-02 at 15:04 +0300, Jonathan Morton wrote:
> > I can easily see a four-tier system working for most consumers, just
> > so long as the traffic for each tier can be identified - each tier
> > would have it's own fq_codel queue:

I generally like it, but some notes below.

> > 1) Network control traffic, eg. DNS, ICMP, even SYNs and pure ACKs -
> > max 1/16th bandwidth, top priority

I used a separate queue for ACK packets, and directly calculated the
needed bandwidth for ACK packets based on the downstream link.

(My future idea was to implement an ACK aware qdisc, that would drop
accumulative ACK packets or delay ACKs to influence downstream behavior)

> > 2) Latency-sensitive unresponsive flows, eg. VoIP and gaming - max
> > 1/4 bandwidth, high priority
> > 
> > 3) Ordinary bulk traffic, eg. web browsing, email, general purpose
> > protocols - no bandwidth limit, normal priority

So, these two above is "known-good" traffic, that gets categorized into

> > 4) Background traffic, eg. BitTorrent - no bandwidth limit, low
> > priority, voluntarily marked, competes at 1:4 with normal.

I worked with two classes for this, (1) a default fall-through traffic
class, where uncategorized traffic end-up. (2) a known "bad" low-prio
traffic class, for traffic I could categorize as BitTorrent etc.


> The above is close to what I implemented:
> http://git.coverfire.com/?p=linux-qos-scripts.git;a=blob;f=src-3tos.sh;h=3e88c2fa5f2feb0163c052086541ba17579a3c37;hb=HEAD

Nice, and thank you for mentioning my (old) site: http://www.adsl-optimizer.dk

And actually have a script that mentions (and can use) the ADSL
linklayer options :-)

> The above aims for per-host fairness and three tiers per host. Each
> tier has an fq_codel QDisc (configurable).
> Some performance results can be found at:
> http://www.coverfire.com/archives/2013/01/01/improving-my-home-internet-performance/

p.s. I love your "ping-exp" tool and the nice graphs it generates!

Others go clone:
 git clone http://git.coverfire.com/ping-exp.git

Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Sr. Network Kernel Developer at Red Hat
  Author of http://www.iptv-analyzer.org
  LinkedIn: http://www.linkedin.com/in/brouer

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