Trouble shooting low rate MCS9 in 802.11ac

[Vu Hai NGUYEN]

>> My 2 devices have an ARM processor 1200MHz.
>> If I connect these two devices by an Ethernet cable and doing iperf (in TCP)
>> I can obtain 880 Mbps, it means that my processor can deal with that speed
>> of data transfer. But if I use Wi-fi instead of Ethernet to test rate between these
>> devices, my processor is exhausted, I run command top and see that 0~1%
>> idle only,  ksoftirqd and kworker take most of my processor resource.
>>
>> Last week I discovered by chance that the module loaded in kernel can create
>> effects to performance of rate, in my case it is "iptables". If I unload all module
>> that related to iptables I can improve the performance.
>> So I wonder if I can do some thing with the Wi-fi driver to  improve rate?
>> Or the only solution is overclock/change my processor?

>Can you run 'perf top' on your system when it is under load so we can
>see where the CPU is being used the most?

It's complicated for me to install "perf" cause it depends on the package linux-tools (please
correct me if I'm wrong :D)and our linux kernel is provided from the processor's producer.
I don't see the option to build "perf" form the menuconfig of our linux. I've enabled these parameters
but still when I run perf from shell there is no program found.

CONFIG_HAVE_PERF_EVENTS=y   
CONFIG_EVENT_TRACING=y     
CONFIG_PERF_EVENTS=y       
CONFIG_PERF_COUNTERS=y     

I can only run "top" to see what process used most of out CPU, they are  ksoftirqd and kworker.

NGUYEN Vu Hai
Acita-Sodielec
Route de Mayres - B.P. 9
12100 St GEORGES DE LUZENCON
FRANCE