* Re: [Bloat] BQL crap and wireless
[not found] <CAB=NE6VuP=AvYiJsYn_Noc1u0Q=jvQPutHRANdSiLP2v48ogfg@mail.gmail.com>
@ 2011-08-31 19:48 ` John W. Linville
0 siblings, 0 replies; only message in thread
From: John W. Linville @ 2011-08-31 19:48 UTC (permalink / raw)
To: Luis R. Rodriguez
Cc: bloat, Andrew McGregor, netdev, linux-wireless, Derek Smithies,
Kevin Hayes, Matt Smith, Tom Herbert
On Fri, Aug 26, 2011 at 04:27:22PM -0700, Luis R. Rodriguez wrote:
> I've just read this thread:
>
> http://marc.info/?t=131277868500001&r=1&w=2
>
> Since its not linux-wireless I'll chime in here. It seems that you are
> trying to write an algorithm that will work for all networking and
> 802.11 devices. For networking is seems tough given driver
> architecture and structure and the hope that all drivers will report
> things in a fairly similar way. For 802.11 it was pointed out how we
> have varying bandwidths and depending on the technology used for
> connection (AP, 802.11s, IBSS) a different number of possible peers
> need to be considered. 802.11 faced similar algorithmic complexities
> with rate control and the way Andrew and Derek resolved this was to
> not assume you could solve this problem and simply test out the water
> by trial and error, that gave birth to the minstrel rate control
> algorithm which Felix later rewrote for mac80211 with 802.11n support
> [1]. Can the BQL algorithm make use of the same trial and error
> mechanism and simply try different values and and use EWMA [2] to pick
> the best size for the queue ?
>
> [1] http://wireless.kernel.org/en/developers/Documentation/mac80211/RateControl/minstrel
> [2] http://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
>
> Luis
Since Luis has stirred things up, I took the liberty of adding Tom's
BQL series to the debloat-testing tree:
git://git.infradead.org/debloat-testing.git
I'm not sure how well BQL will interact with my eBDP-inspired hack,
debloat-testing commit d2566a176589775cb3a1de4fade972aa62d551ff
("mac80211: implement eBDP algorithm to fight bufferbloat"). So if
anyone wants to try enabling a wireless driver for BQL, you might
consider reverting that patch or at least testing without it.
<shameless plug>
And, of course, don't forget to come to the Bufferbloat and Networking
track at Linux Plumbers Conference next week in Santa Rosa, CA! :-)
</shameless plug>
John
--
John W. Linville Someday the world will need a hero, and you
linville@tuxdriver.com might be all we have. Be ready.
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