Hi all,
I just tried out compat-wireless-2010-07-16 on AR913x (with
openwrt/trunk@r22321) and saw some weird performance problems.
First, with the default 11n HT20 AP configuration I get really good
performance on an old 11g MacBook. 16Mbps downloads limited by WAN. :)
But then I try a newer 11n MacBook and performance absolutely sucks.
2-3Mbps downloads with erratic bursts and "hangs".
So, I start to think something is wrong with 11n and reconfigure for
11g only. Then the 11g MacBook performance also sucks. The same
2-3Mbps downloads with erratic bursts and "hangs". So 11n AP and 11g
client is good, but 11g AP and 11g client sucks. Looking at the
rc_stats it seems like tx completely breaks down from time to time:
root@OpenWrt:/sys/kernel/debug/ieee80211/phy0# cat stations/00\:17\:f2\:51\:b2\:
2d/rc_stats
rate throughput ewma prob this prob this succ/attempt
success attempts
t 1 0.1 18.3 0.0 0( 19) 28 731
2 0.0 0.0 0.0 0( 0) 0 18
5.5 0.0 0.0 0.0 0( 0) 0 10
11 0.0 0.0 0.0 0( 0) 0 14
6 0.0 0.0 0.0 0( 0) 0 11
9 0.0 0.0 0.0 0( 0) 0 18
12 0.0 0.0 0.0 0( 0) 0 12
18 0.0 0.0 0.0 0( 0) 0 16
24 0.0 0.0 0.0 0( 0) 0 18
36 0.1 0.4 0.0 0( 0) 2 1824
48 0.0 0.0 0.0 0( 2) 0 16
T P 54 27.3 63.1 0.0 0(180) 4749 13896
Total packet count:: ideal 4780 lookaround 532
That's in exactly the same spot I was getting 16Mbps consistently with
AP was 11n!
Any debuging I can do to help? Bisecting is unfortunately a lot of
work on this embedded system...
/Björn
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