[Cerowrt-devel] the agile thread, post-sugarland thoughts, etc

[Dave Taht]

I am enjoying the thread on agile over here: http://esr.ibiblio.org/?p=4564

Trying to formalize some stuff that I do instinctively into language
more folk grok would be good.

One of the better links to come from it was this one:

http://blogs.valvesoftware.com/abrash/valve-how-i-got-here-what-its-like-and-what-im-doing-2/

This is something like what we've done with the bufferbloat effort -
find something worthwhile, start a project to do it. However steam has
a revenue model that we thus far lack. It does help to be making
something lots of people want, and I suppose the hard problem is
making people aware we have something they want.

Speaking of that, the 3.6-rc6 kernel I was working on which has most
of the cerowrt stuff in it, but for x86 and ubuntu is here:
http://snapon.lab.bufferbloat.net/~cero1/deb/

and (in trying to lick the memory problems) I've been doing some
builds for the 32MB ram nanostation M5 and picostation 2HP, based on
the current cerowrt patch sets. With a single SSID I haven't been able
to crash the 2HP yet with a variety of traffic. It's easy to calculate
however how to crash nearly any access point with extra SSIDs

if (Total spare ram - (4 wireless queues, 1000 packets = 2Mbytes
roughly for each = 8Mbytes) * SSIDS) < 0)
          boom()

This would be improvable with a multi hw queue fq_codel as each
hardware queue could share an overall fq_codel queue (factor of 4
decrease), however, it seems to make more sense to have the queueing
in the mac layer below the SSID abstractions.

What's currently in cerowrt is eric dumazet's suggestions to reduce
packet allocations under load. The above math was worse before - no
matter the packet size, it seemed as though 2k and 4k allocations
would be exausted.

...

After I recover from the sprint required to get "sugarland" out the
door, I'd like to work on ways to do scrum and sprint-like things
(google hangouts?) to spread the knowledge and work around, and to
parallelize the effort more.
So much work remains. Truly addressing the wireless problem hasn't
even started.

I have to admit that after doing something like 30 official releases
of cerowrt out the last 18 months, I'd
really like to hand over the reins to that to someone else. Worse is
after the openwrt unfreeze, new kernels will start to appear, and
while working with Linux 3.6 and later would be helpful, I'd rather
have stability for a while to work on higher layers of the stack, and
get analytical. Doing both "stable" maintainence and trying to move
forward on new kernels is a problem...

Next up for me is working on qos-scripts, analytical models and tests,
and updating my test deployment to
this generation of code if all goes well. I just dumped a ton of raw
data into the deBloat repo, too. Also have a few patches for the linux
and openwrt mainlines to polish...

On other fronts, I'm still working the basic funding angles and trying
to fix things with amazon. I was encouraged enough by your (thus far
failed) attempts at financial help to sink the time I did into
sugarland (sugar helped too, I think she needs a job title). If it
wasn't for the outpouring of your support, I'd have given up. Thx. I
sure hope sugarland is better than -10.

There has been an upswing in corporate interest in the last few weeks,
I may have some news on that shortly.

I had planned originally to get to barcelona for the wireless summit
and the linux conference. I may still make the second (issue is in
doubt, though). Is anyone besides jg going to this?

http://www.wirelesssummit.org/

It's near the home of guifi.net which is one of the larger wireless
networks I've ever heard of.

--
Dave Täht
http://www.bufferbloat.net/projects/cerowrt/wiki - "3.3.8-26 is out
with fq_codel!"