rt73usb rate control

Live forum: http://rt2x00.serialmonkey.com/viewtopic.php?t=4839

chrisV

08-06-2008 20:50:47

I have been comparing the version of the rt73usb driver in the vanilla 2.6.26-rc5 kernel with the current version in the master branch of rt2x00 git.

Both work well for me except that with rt2x00 git, automatic rate control does not work. With vanilla 2.6.26-rc5 automatic rate control does what is expected and with a reasonable signal will pick a rate of 54Mb/s. Transfer speed is extremely good - on a largish file (I tested it with evolution-2.22.1.tar.bz2) scp reports a transfer speed of 2.6MB/s (bytes not bits) which must be not a great deal short of the theoretical maximum for a 54M wireless bit rate, given overheads.

With rt2x00 git, automatic rate control does not work - the speed is stuck at 1Mb/s and does not change. If I set a fixed rate with 'iwconfig wlan0 rate 54M fixed' I get transfer speeds similar to vanilla 2.2.26, but resetting it with 'iwconfig wlan0 54M auto' causes speed to deteriorate rapidly to 1Mb/s again.

In both cases I have the pid rate control algorithm compiled in.

Apart from automatic rate selection, these are encouraging results speed-wise.

Chris

IvD

08-06-2008 20:53:51

looking at the number of threads who all report the same thing, I can conclude this is a known issue. ;)

chrisV

08-06-2008 20:58:34

looking at the number of threads who all report the same thing, I can conclude this is a known issue. ;)[/quote30jha4rd]

Well there is a little more information than that you know that on my rt73 stick everything else works well (and that vanilla 2.6.26 is good to go on rate control).

Chris

IvD

08-06-2008 21:03:13

Thats true. Especially since I was worried most drivers were currently broken in rt2x00.git. ;)
As for the rate control in 2.6.26 that seems to change per -rc release S

chrisV

08-06-2008 21:10:01

Thats true. Especially since I was worried most drivers were currently broken in rt2x00.git. ;)[/quote35saku2h]
They are broken in wireless-testing (or at any rate, rt73 is and does some impressive spamming of my syslog).

Chris

IvD

08-06-2008 21:48:53

I just send a patch upstream that might solve that. (I assume the log is spammed with stack traces or something?)

chrisV

08-06-2008 22:51:44

I just send a patch upstream that might solve that. (I assume the log is spammed with stack traces or something?)[/quotel2g3geed]
Yes.