Re: Connection problems with wme enabled

From: Fabian Keil <freebsd-listen_at_fabiankeil.de>
Date: Fri, 2 May 2008 13:15:23 +0200
Sam Leffler <sam_at_freebsd.org> wrote:

> Fabian Keil wrote:
> > Sam Leffler <sam_at_freebsd.org> wrote:
   
> >> Fabian Keil wrote:
> >>     
> >>> Sam Leffler <sam_at_freebsd.org> wrote:

> >> wlanstats 1 gives you a rolling display every second; that's usually 
> >> more helpful in understanding what's happening.  Unfortunately there are 
> >> more stats than can fit on a rolling display so sometimes the one(s) you 
> >> want aren't shown.  There is a column fmt mechanism a la ps to control 
> >> output but it's not well developed (someone please take and improve).  
> >> Also some stats are maintained by drivers and not yet counted in the 
> >> net80211 layer (again, folks are welcome to help).
> >>     
> >
> > While working:
> >
> > fk_at_TP51 ~ $wlanstats 1
> >    input 2short rx_ucast bvers wrbss rxdup mecho wrdir
> >       14     0       14     0     1 29861    54     0
> >       19     0       19     0     0     0     0     0
> >        7     0        7     0     0     0     0     0
> >       15     0       15     0     0     0     0     0
> >       14     0       14     0     0     0     0     0
> >        4     0        4     0     0     0     0     0

> >        1     0        1     0     0     0     0     0
> > ^C
> >
> > While "hanging" ...
> >
> > fk_at_TP51 ~ $wlanstats 1
> >    input 2short rx_ucast bvers wrbss rxdup mecho wrdir
> >      882     0      831     0     1 29859    50     0
> >        1     0        0     0     0     0     0     0
> >        0     0        0     0     0     0     0     0
> >        1     0        0     0     0     0     0     0
> >        0     0        0     0     0     0     0     0

> >        0     0        0     0     0     0     0     0
> > ^C

> Your code is out of date, I just imported some fixes yesterday :)

Indeed.

While "hanging":

fk_at_TP51 ~ $wlanstats 1
   input     mgmt   output rxkid ascan bgscn bmiss  rssi noise  rate
     113      591      207     0    10     0     3    42     0   54M
       0        0        2     0     0     0     0    42     0   54M
       0        0        1     0     0     0     0    42     0   54M
       0        0        2     0     0     0     0    42     0   54M
       0        0        2     0     0     0     0    42     0   54M
       0        1        1     0     0     0     0    42     0   54M
       0        0        1     0     0     0     0    42     0   54M
       0        0        2     0     0     0     0    42     0   54M
       0        0        1     0     0     0     0    42     0   54M
       0        0        2     0     0     0     0    42     0   54M
       1        1        3     0     0     0     0    43     0   54M
       0        0        1     0     0     0     0    43     0   54M
       0        0        2     0     0     0     0    43     0   54M
       0        0        2     0     0     0     0    43     0   54M
       0        0        2     0     0     0     0    43     0   54M
       0        1        3     0     0     0     0    42     0   54M
       0        0        1     0     0     0     0    42     0   54M
       0        0        2     0     0     0     0    42     0   54M
^C

While working with wme enabled:

       7        0        7     0     0     0     0    42     0    2M
       4        0        4     0     0     0     0    42     0   11M
      10        0        6     0     0     0     0    42     0   11M
       5        0        4     0     0     0     0    43     0   12M
       5        1        3     0     0     0     0    43     0   12M
       3        0        4     0     0     0     0    43     0   18M
       3        0        3     0     0     0     0    43     0   18M
       4        0        3     0     0     0     0    43     0   18M
       3        0        2     0     0     0     0    43     0   18M
       3        1        4     0     0     0     0    43     0   24M
   input     mgmt   output rxkid ascan bgscn bmiss  rssi noise  rate
      80      756       67     0    17     0     3    43     0   36M
       3        0        3     0     0     0     0    43     0   36M
       4        0        4     0     0     0     0    43     0   48M
       2        0        2     0     0     0     0    43     0   48M
       3        1        5     0     0     0     0    43     0   48M
       2        0        4     0     0     0     0    43     0   48M
       1        0        4     0     0     0     0    43     0   54M
       2        0        3     0     0     0     0    43     0   54M
       3        0        5     0     0     0     0    43     0   54M
       4        1        6     0     0     0     0    43     0   54M
       2        0        4     0     0     0     0    43     0   54M
       3        0        4     0     0     0     0    43     0   54M
       2        0        4     0     0     0     0    43     0   54M
       1        0        2     0     0     0     0    43     0   54M
^C

While working with wme disabled:

fk_at_TP51 ~ $wlanstats 1
   input     mgmt   output rxkid ascan bgscn bmiss  rssi noise  rate
      21      633       19     0    12     0     3    41     0    5M
       4        0        3     0     0     0     0    41     0    5M
       4        0        3     0     0     0     0    41     0    5M
       2        1        2     0     0     0     0    42     0    5M
       5        0        5     0     0     0     0    42     0   11M
       4        0        7     0     0     0     0    42     0   11M
       7        0        4     0     0     0     0    42     0   12M
       7        0        7     0     0     0     0    42     0   12M
       8        1        5     0     0     0     0    42     0   18M
       7        0        5     0     0     0     0    42     0   18M
       2        0        2     0     0     0     0    42     0   24M
       4        0        3     0     0     0     0    42     0   24M
       2        0        2     0     0     0     0    43     0   18M
       3        1        3     0     0     0     0    42     0   18M
       3        0        2     0     0     0     0    42     0   18M
       2        0        2     0     0     0     0    42     0   18M
       4        0        3     0     0     0     0    42     0   18M
       2        0        2     0     0     0     0    42     0   18M
       3        1        3     0     0     0     0    42     0   18M
       7        0        6     0     0     0     0    42     0   18M
^C

> >>> It's interesting that with wme enabled the hangs
> >>> usually occur with the transmit rate at 54, while
> >>> it's usually a lot lower with wme disabled and the
> >>> device working.
> >>>       
> >
> >   
> >> iwi does tx rate control in the firmware so unlikely to be related.  The 
> >> more likely issue is the beacon miss handling.  The driver should 
> >> recover and reconnect but it sounds like something didn't work.  As a 
> >> workaround you can try upping the bmiss count to see if this is a 
> >> problem w/ the radio going deaf for a period of time--something I've 
> >> seen on older Intel parts.
> >>     
> >
> > Increasing bmiss to 250 (or decreasing it to 10)
> > doesn't seem to affect the problem.
> >   
> 
> Well if your beacon interval is 100 TU then the default setting of 24 
> means you didn't see a beacon frame in 2400 TU (~2.4 seconds) which is a 
> really long time even if the channel is way busy.  The firmware handles 
> this notification so it could be a firmware issue; if I were 
> investigating I'd sniff packets to see.
> 
> I've tested bmiss handling before (yesterday even) and it worked for me 
> w/ and w/o wme enabled so not sure what to say.  What I have noticed is 
> the firmware some times delivers a slew of beacon miss notifications 
> immediately after associating to an ap.  I have some ideas why this 
> might occur but Intel wouldn't answer when asked.  However if you're 
> seeing bmiss after lots of traffic has passed then it's unclear what's 
> happening.
> 
> I tested mostly with a 2915 card fwiw.

> >> See above.  I ran tests yesterday w/ wme enabled in my environment but 
> >> the signal was stronger so not an equivalent test.  What you need to do 
> >> is get a log that captures the event of losing connectivity.  This must 
> >> include net80211 logging and probably needs to include some level of 
> >> driver debugging as the problem is in the driver.  Try:
> >>
> >> wlandebug state+scan+auth+assoc
> >>     
> >
> > fk_at_TP51 ~ $sudo wlandebug state+scan+auth+assoc
> > wlandebug: sysctl-get(net.wlan.0.debug): No such file or directory
> >
> > fk_at_TP51 ~ $sysctl net.wlan     
> > net.wlan.addba_maxtries: 3
> > net.wlan.addba_backoff: 10000
> > net.wlan.addba_timeout: 250
> > net.wlan.cac_timeout: 60
> > net.wlan.nol_timeout: 1800
> > net.wlan.recv_bar: 1
> > net.wlan.0.%parent: iwi0
> > net.wlan.0.driver_caps: 92307968
> > net.wlan.0.bmiss_max: 200 (increased by me, without noticeable effect)
> > net.wlan.0.inact_run: 300
> > net.wlan.0.inact_probe: 30
> > net.wlan.0.inact_auth: 180
> > net.wlan.0.inact_init: 30
> >
> >   
> >> sysctl debug.iwi=5
> >>     
> >
> > I'm not sure how useful it is without net80211 logging,
> > but I uploaded 160K of iwi0 messages at:
> >
> > http://www.fabiankeil.de/tmp/freebsd/iwi0-messages.txt

> Looks like I failed to include IEEE80211_DEBUG in the default kernel 
> configs; you'll need that to get wlan debug msgs.  I'll try to look at 
> your log later.

I uploaded a log with IEEE80211_DEBUG enabled at:
http://www.fabiankeil.de/tmp/freebsd/wlan0+iwi0-messages.txt

Fabian

Received on Fri May 02 2008 - 09:15:31 UTC

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