[Performance regression] BCM4359/9 on S905X2

[Marc Gonzalez]

Hello everyone,

I've been benchmarking an Amlogic S905X2 board.
It provides a BCM4359/9 WiFi chip connected through SDIO.

There's a large performance gap between vendor kernel and mainline.
(Downloading a 1GB file to /dev/null from a device inches away)

# curl -o /dev/null http://192.168.1.254:8095/fixed/1G
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1024M  100 1024M    0     0  27.5M      0  0:00:37  0:00:37 --:--:-- 28.6M
vs
100 1024M  100 1024M    0     0  11.0M      0  0:01:32  0:01:32 --:--:-- 11.0M

Line 1 = vendor kernel (4.9.180 amlogic android)
Line 2 = mainline kernel (6.2.0-rc8)

Why is the vendor kernel 2.5 times faster?

(I'm using the same firmware files, but it seems the vendor kernel reads
an additional configuration file that the mainline vendor seems to ignore.)

Regards