Cédric Auger wrote:
Le Sat, 26 Jul 2008 10:54:41 -0500,
Larry Finger <Larry.Finger@xxxxxxxxxxxx> a écrit :
Felix Fietkau wrote:
I don't know if it helps with debugging this issue, but I've seen
the same on a laptop from a friend of mine (same card).
After some searching I found that setting the AP to g-only mode
instead of b+g mixed made it work at decent speeds. Another symptom
of this slowdown is that there is typically an unnaturally high
number of retransmissions on the air, which eats up a lot of
airtime.
I've spent some time looking through the code to find the reason
for this but couldn't find anything yet (maybe somebody from Intel
could help).
Just for comparison, my BCM4312 running b43 from the latest
wireless-testing gets the following tcpperf throughput:
AP Mode TX RX
Mixed b/g 19.8 MB/s 23.0 MB/s
g-only 20.5 MB/s 23.1 MB/s
For these tests, the connecting end was wired to the router. The
difference in TX speeds was about what I expected - the small
difference in RX speeds was not. In any case, if you see a large
difference with iwl3945, that would be useful information.
You can obtain tcpperf from
http://wand.cs.waikato.ac.nz/~stj2/nsc/software.html
hello
thanks for your answers.
i tried to set my ap to g-only, but i cannot :-( the wifi box is given
by my provider and it seems cannot be changed...
so i tried tcpperf, this is the result :
cedric:/home/grisbi/tcpperf-1.754# ./tcpperf -c 192.168.0.4 -t 30
Duration: 30 9482usec
Bytes sent: 5481472 (5353 kB 5 MB 0 GB)
Bandwidth: 1461264 b/s (1461.26 kb/s 1.46 Mb/s)
Close duration: 0s 22usec
then i tried to download an image of ubuntu and i had about 900kb/s,
so very good and i don't understand... then i tried to send a big file
with scp to the other computer, as user and as root, it begins at
2,2MB/s and decrease untill 150kb/s and stays between 130-200kb/s
i did again a tcpperf with -t 300 to check if it's not with the time,
but i have 1,30MB/s, seems correct.
second test :
i stop the wifi and plug a cable. the second computer is still in wifi.
tcpperf gives me 17Mb/s and the same file with scp is sent with about
2,2MB/s...
so now i really don't understand, from internet, loading work untill
900kb/s (ok for me), but beween 2 computers on my network i have max
200kb/s...
hopes this can be usefull
It looks as if your receive rate is a lot higher than the transmit rate. You can
check that by using the computer with the iwl3945 as the server and initiate
tcpperf from the other end.
Larry
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