Bad host-vased AP performace -- and qouple of questions about FreeBSD WiFi stack tuning

Lev Serebryakov lev at serebryakov.spb.ru
Mon Aug 8 21:03:46 UTC 2011


Hello, Adrian.
You wrote 8 августа 2011 г., 22:26:54:

> That's definitely required knowledge. 8.0-RELEASE is a good starting point.
> I'm afraid it's going to be difficult for me to narrow down what's
> changed without you doing a bit of legwork to find which kernel
> version(s) introduced the performance regression.
> Once we narrow that down, I'll fix it. :)
> Please keep everything else the same though, including the laptop. :)
  It seems, that 8.0-RELEASE behaves slightly different from very
fresh 8-STABLE, but I can not say that it is much better. It is output
from `list sta' when  notebook (client) is placed exactly the same
point as previous experiment:

00:18:de:08:e8:1d    1    9  36M 17.5    0  54585  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  36M 16.0    0  55126  46112 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  36M 17.5    0  55648  50832 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  36M 16.0    0  56169  55632 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  36M 16.0    0  56615  59664 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  24M 16.0    0  57195  65072 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  24M 17.5    0  57936  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  24M 17.0    0  58178  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  24M 16.0    0  58903  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  24M 16.5    0  59465  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  54M 17.5    0  59954  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  54M 17.5    0  60591  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  36M 16.0    0  61343  41344 EPS  AQE     RSN WME

  It looks like it doesn't drop under 24M now. BUT! When I move
notebook into direction of AP (into other room, which is near AP) I've
got:

00:18:de:08:e8:1d    1    9  12M 29.0    0  21255  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  12M 28.0    0  22031  46560 EPS  AQEP    RSN WME
00:18:de:08:e8:1d    1    9  12M 30.5    0  22291  46576 EPS  AQEP    RSN WME
00:18:de:08:e8:1d    1    9  12M 30.5    0  22291  46576 EPS  AQEP    RSN WME
00:18:de:08:e8:1d    1    9  12M 30.5    0  22291  46576 EPS  AQEP    RSN WME
00:18:de:08:e8:1d    1    9  12M 30.5    0  22291  46576 EPS  AQEP    RSN WME

  And after door is closed:

00:18:de:08:e8:1d    1    9  12M 23.0    0  27276  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  12M 22.0    0  27789  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  11M 22.5    0  28134  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  11M 22.5    0  28730  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  11M 21.5    0  29040  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  11M 21.5    0  29369  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  12M 22.5    0  29822  41344 EPS  AQE     RSN WME
00:18:de:08:e8:1d    1    9  11M 21.0    0  30232  41344 EPS  AQE     RSN WME

  Better RSSI but much worse speed?!

  I don't have second notebook on hands now to monitor does speed hops
 up and down, but ``ifconfig wlan0 list sta'' every second gives all
 this output.

  It looks like it never works at full and stable 54M now, even if notevook in
direct sight to AP within ~1 meter:

00:18:de:08:e8:1d    1    9  36M 37.5    0  44443  53936 EPS  AQEP    RSN WME
00:18:de:08:e8:1d    1    9  36M 37.5    0  44443  53936 EPS  AQEP    RSN WME
00:18:de:08:e8:1d    1    9  36M 37.5    0  44443  53936 EPS  AQEP    RSN WME
00:18:de:08:e8:1d    1    9  36M 37.5    0  44443  53936 EPS  AQEP    RSN WME
00:18:de:08:e8:1d    1    9  36M 37.5    0  44443  53952 EPS  AQEP    RSN WME
00:18:de:08:e8:1d    1    9  36M 37.5    0  44443  53984 EPS  AQEP    RSN WME

 And it seems, that in any other situation it works worse, that it
theoretically can.

 Unfortunately, mini-PCI WiFi cards is not easy to get (and almost
impossible to borrow for free, even for short time) here, and I can
not replace this card in AP and try with another one :(

 I'll try to build 7-STABLE system, but it will take more time, as I
need to adapt configs for it.

-- 
// Black Lion AKA Lev Serebryakov <lev at serebryakov.spb.ru>



More information about the freebsd-wireless mailing list