On Sat, May 27, 2017 at 08:31:23PM -0400, Maximilian Pichler wrote:
> I've tried a PPD-AR5BHB92-H (AR9280 miniPCIe) in AP mode and connected
> clients get ~12 Mbit/s downstream and ~35 Mbit/s upstream (i.e. the
> card appears to receive data much faster than it sends). Selecting a
> less crowded 5GHz channel helped quite a bit. Is this performance more
> or less what is currently to be expected?
There is an issue where the card won't transmit at rates beyond 18M / MCS 12.
Whenever rate scaling selects a higher transmit rate it drops back down
right away, even on a clean channel. I haven't figured out why.
I expect fixing this will involve a dive into the dark magic of the
chip's low-level configuration since it looks as if OFDM modulations
at the higher end don't work (and never ever worked) with our driver.
Also, we do not support Tx aggregation in 11n mode yet.
This is why other 11n implementations manage to send more data
per second at a given data rate than we do.
> The measurements were conducted by running the following commands on a
> Macbook connected to the AP's wireless network:
>
> $ for i in {1..10}; do nc 192.168.0.1 1234 | dd of=/dev/null
> count=10240 bs=1000; sleep 1; done 2>&1 | grep trans
> 6899272 bytes transferred in 4.307439 secs (1601711 bytes/sec)
> 6864520 bytes transferred in 4.275299 secs (1605623 bytes/sec)
> 6837456 bytes transferred in 4.256377 secs (1606403 bytes/sec)
> 6734200 bytes transferred in 4.194057 secs (1605653 bytes/sec)
> 6952848 bytes transferred in 4.311542 secs (1612613 bytes/sec)
> 6898272 bytes transferred in 4.294667 secs (1606241 bytes/sec)
> 6867864 bytes transferred in 4.256106 secs (1613650 bytes/sec)
> 6906512 bytes transferred in 4.291027 secs (1609524 bytes/sec)
> 6757816 bytes transferred in 4.182866 secs (1615595 bytes/sec)
> 6871760 bytes transferred in 5.059761 secs (1358119 bytes/sec)
>
> $ for i in {1..10}; do dd if=/dev/urandom count=10240 bs=1000 | nc
> 192.168.0.1 1234; sleep 1; done 2>&1 | grep trans
> 10240000 bytes transferred in 2.290328 secs (4470975 bytes/sec)
> 10240000 bytes transferred in 2.251763 secs (4547548 bytes/sec)
> 10240000 bytes transferred in 2.160710 secs (4739183 bytes/sec)
> 10240000 bytes transferred in 2.031869 secs (5039695 bytes/sec)
> 10240000 bytes transferred in 2.215611 secs (4621750 bytes/sec)
> 10240000 bytes transferred in 3.615391 secs (2832335 bytes/sec)
> 10240000 bytes transferred in 2.340003 secs (4376063 bytes/sec)
> 10240000 bytes transferred in 2.185185 secs (4686102 bytes/sec)
> 10240000 bytes transferred in 2.509382 secs (4080686 bytes/sec)
> 10240000 bytes transferred in 2.333018 secs (4389164 bytes/sec)
>
> On the AP box:
> $ nc -kl 1234 < /dev/urandom
> $ nc -kl 1234 > /dev/null
Thanks for sharing this.
