Flemming Frandsen wrote:
> Hi, I'm using Atheros 5212 minipci cards with the latest linux driver
> (from SVN) and I find that I cannot get more than 24Mb/s out of the
> wireless link, is that normal?
Did you ask on the madwifi lists? I routinely get 28 Mb/s for upstream
tcp netperf w/ bursting enabled. Unidirectional udp tests usually get
36 Mb/s. All numbers are open air w/ strong signal. freebsd, not linux.
>
> I've tested it by routing traffic through the link and running iperf on
> separate machines, so nothing runs on the net4801 machines other than
> the kernel and top.
>
> I first tried setting one box to AP and the other to Sta and that got me
> 13Mb/s with the CPU maxed out, when I switched to ahdemo mode (like
> adhoc, but without any fancy stuff like mac addresses) that got me 22Mb/s.
>
> Then I upgraded to the very latest driver and that got me 24Mb/s, but
> the CPU is still the bottleneck, which is really quite sad as I was
> hoping to saturate the wireless link.
>
> One could argue that I'm simply trying to go faster than the cpu allows,
> but I get 50Mb/s if I iperf to the box from eth0, so the CPU should be
> capable of routing that much, right?
>
> I guess my main questions are:
> * Is this really all I can hope for with Atheros cards?
> * If it's the card that has been designed to eat CPU then are there
> others that do more work in hardware?
> * On paper the net5501 looks to be about twice as fast as net4801,
> which is not quite enough to reach the performance I want, how does
> the net5501 CPU perform compared to net4801?
>
>
> Max at 54Mb/s (CPU maxed out):
> AP/STA mode: 13Mb/s
> ahdemo mode: 22Mb/s
> New driver: 24Mb/s
>
> 802.11a (ch 136):
> Bit Rate=54 Mb/s : 24.3Mb/s (0% idle)
> Bit Rate=36 Mb/s : 16Mb/s (15% idle)
> Bit Rate=24 Mb/s : 15Mb/s (37% idle)
> Bit Rate=6 Mb/s : 4.3Mb/s (81% idle)
>
> 802.11Ta (ch 152):
> Bit Rate=54 Mb/s : 23.5Mb/s
> Bit Rate=36 Mb/s : 23.5Mb/s
> Bit Rate=24 Mb/s : 23.9Mb/s
> Bit Rate=12 Mb/s : 17Mb/s
> Bit Rate=6 Mb/s : 9Mb/s
>
> The driver version is:
> ath_hal: 0.9.30.13 (AR5210, AR5211, AR5212, AR5416, RF5111, RF5112,
> RF2413, RF54
> 13, RF2133)
> wlan: 0.8.4.2 (svn r2377)
> ath_pci: 0.9.4.5 (svn r2377)
> ath_rate_sample: 1.2 (svn r2377)
>
You need to ask the madwifi folks for help. I recently had an exchange
w/ a developer who was trying to reduce cpu overhead but a 4801 should
be able to easily saturate the wireless link.
Sam
_______________________________________________
Soekris-tech mailing list
[email protected]
http://lists.soekris.com/mailman/listinfo/soekris-tech
