When my BCM4312 (ID 4315) runs in auto rate mode, the rate stays at
1Mb/s. If I manually set the rate, I see a tcpperf throughput ~1/2 the
rate that I set through a rate of 12 Mb/s. At 36 Mb/s, the rate is
best at 15.7 Mb/s. Why does mistrel not increase the rate?
The output of /sys/..../rc_stats is:
finger@larrylap:~> cat
/sys/kernel/debug/ieee80211/phy0/stations/00:14:bf:85:49:fa/rc_stats
rate throughput ewma prob this prob this succ/attempt
success attempts
1 0.9 99.1 100.0 0( 0) 3244
3282
2 1.8 95.7 100.0 0( 0) 12
12
5.5 4.8 95.7 100.0 0( 0) 12
12
11 9.2 96.8 100.0 0( 0) 12
12
P 6 5.6 99.9 100.0 0( 0) 58
58
9 8.0 95.7 100.0 0( 0) 11
11
12 10.6 95.7 100.0 0( 0) 12
12
18 15.7 96.6 100.0 0( 0) 14
15
24 20.3 95.7 100.0 0( 0) 11
11
36 29.0 95.4 94.5 0( 0) 1602
1670
T 48 38.7 99.2 100.0 1( 1) 32147
37752
t 54 32.9 75.9 100.0 0( 0) 8775
12788
Total packet count:: ideal 2570 lookaround 135
Actually, the rate-setting mechanism is working. If I looked at the
iwconfig rate while a transmission was in progress, the rate toggled
between 48 and 54 Mb/s. When I checked between tests, it showed 1
Mb/s, which is what fooled me.
The rc_stats table is:
rate throughput ewma prob this prob this succ/attempt
success attempts
P 1 0.9 99.9 100.0 0( 0) 314
314
2 1.8 96.9 100.0 0( 0) 15
16
5.5 4.8 95.7 100.0 0( 0) 12
12
11 9.5 99.9 100.0 0( 0) 134
138
6 5.4 95.7 100.0 0( 0) 11
11
9 8.0 95.7 100.0 0( 0) 11
11
12 10.6 95.7 100.0 0( 0) 11
11
18 15.5 95.5 100.0 0( 0) 12
13
24 20.3 95.7 100.0 0( 0) 12
12
36 29.3 96.5 96.4 0( 0) 4118
4249
T 48 37.6 96.3 100.0 23( 23) 376174
414958
t 54 36.8 84.8 81.5 62( 76) 356248
427489
Total packet count:: ideal 6627 lookaround 348
The automatic throughput is about 13 Mb/s.
Larry
Larry Finger wrote:
> When my BCM4312 (ID 4315) runs in auto rate mode, the rate stays at
> 1Mb/s. If I manually set the rate, I see a tcpperf throughput ~1/2 the
> rate that I set through a rate of 12 Mb/s. At 36 Mb/s, the rate is
> best at 15.7 Mb/s. Why does mistrel not increase the rate?
>
> The output of /sys/..../rc_stats is:
>
> finger@larrylap:~> cat
> /sys/kernel/debug/ieee80211/phy0/stations/00:14:bf:85:49:fa/rc_stats
> rate throughput ewma prob this prob this succ/attempt
> success attempts
> 1 0.9 99.1 100.0 0( 0) 3244
> 3282
> 2 1.8 95.7 100.0 0( 0) 12
> 12
> 5.5 4.8 95.7 100.0 0( 0) 12
> 12
> 11 9.2 96.8 100.0 0( 0) 12
> 12
> P 6 5.6 99.9 100.0 0( 0) 58
> 58
> 9 8.0 95.7 100.0 0( 0) 11
> 11
> 12 10.6 95.7 100.0 0( 0) 12
> 12
> 18 15.7 96.6 100.0 0( 0) 14
> 15
> 24 20.3 95.7 100.0 0( 0) 11
> 11
> 36 29.0 95.4 94.5 0( 0) 1602
> 1670
> T 48 38.7 99.2 100.0 1( 1) 32147
> 37752
> t 54 32.9 75.9 100.0 0( 0) 8775
> 12788
>
> Total packet count:: ideal 2570 lookaround 135
Was this dump made after you played with manual rate settings? If so,
please make a new one that only contains stats of what it tried with
automatic rate setting enabled.
- Felix