Subject: Re: [mac80211 ] Wifi Network slownes bisected

From: Alejandro Riveira Fernández<[email-masked]>
Date: Thu, 21 May 2009 19:18:17 +0200

El Thu, 21 May 2009 18:08:11 +0200
Johannes Berg <[email-masked]> escribió:

> On Thu, 2009-05-21 at 17:38 +0200, Alejandro Riveira Fernández wrote:
> 
> >  I noticed that my wifi connection has slowed when stitching
> > from 2.6.29.1 to 2.6.29.4 (it is also slow on 30-rc6)
> > Also 2.6.27 (ubuntu) does not suffer it.
> 
> > $ git bisect good
> > 64e1b00c974ddeae6a60ebb02e1c487371905cea is first bad commit
> > commit 64e1b00c974ddeae6a60ebb02e1c487371905cea
> > Author: Johannes Berg <[email-masked]>
> > Date:   Fri Apr 24 16:05:16 2009 +0000
> > 
> >     mac80211: fix basic rate bitmap calculation
> 
> Well ... How much did your connection slow down? 

  Enough to notice it when connecting through a 3MBit
 Adsl connection i.e. with the patch i get 30 40 60 ...
 80 kiB maximum without it full 310 KiB so it is an issue
 for me (i have inet <-> modem-router <-> myPC only so i can
 not test with another pc)

> It is clear that this
> commit might possibly slow down your connection, but not by a lot.

 Well it does by a lot avg of 60 KiB vs 300 KiB is lot for me

 And that's only because before we were sending with a higher rate than the
> AP allowed us to... If you need the higher speed then set your AP to
> G-only to make it include more rates in the basic rate set, that'll
> speed up your connection properly.

 My Ap is set to "mixed" but i connect at G speeds ie iwconfig show 54M or 48M
 or 36M but the connection is slow nonetheless 
 Do you think that would make such a difference (the ap mode)?

 Also with the patch i notice weird bumps on connection rates and without it
 the connection "feels" more stable
 
 > 
> That's all discounting driver bugs which may exist, of course.

 well i bisected and the problem is with this commit. Could be
 that rt2x00 is doing something wrong with that "rate bitmap" ??
 I'm not programmer so i can not check myself

> johannes

Alejandro

  Thanks for the response...