Performance of rtw88_8822bu

[Larry Finger <Larry.Finger@xxxxxxxxxxxx>]

Sascha an Ping-Ke,

I have been testing the RTW8822BU driver found in my rtw88 GitHub repo. This 
code matches the code found in wireless-next. I created 9 files of 5.8 GiB each 
and used a for loop to copy them from the test computer to/from my server. The 
wireless connection is on the 5 GHz band (channel 153) connected to an ax1500 
Wifi 6 router, which in turn is connected to the server via a 1G ethernet cable. 
The connection has not crashed, but I see strange behavior.

With both TX and RX, the rate is high at 13.5 MiB/s for RX and 11.1 MiB/s for TX 
for about 1/3 of the time, but then the driver reports "timed out to flush queue 
3" and the rate drops to 3-5 MiB/s for RX and 2-3 MiB/s for TX. These low rates 
are in effect for 2/3 of the time. The 5G bands are relatively unused in my 
house, thus I do not suspect interference.

Any idea why the timeout errors are occurring? They definitely kill the 
throughput. If you are interested, I have a photo of the TX throughput vs time.

Larry