Using the NEON floating-point accelerator

[oscar...@gmail.com]

I have a library that requires lots of calculations so I need to use the NEON FPA.

I noticed that it wasn't using it because I compiled a code inside the ardupilot examples libraries (libraries/AP_HAL/example/Printf) with my library and the same code outside of it and it gave me significant different performance so I am thinking it must be because of this. I know that the CPU is running at 1 GHz in both tests because have it as default

sudo sed -i 's/GOVERNOR="ondemand"/GOVERNOR="performance"/g' /etc/init.d/cpufrequtils

and

root@beaglebone:/home/debian/ardupilot/build/blue/examples# rc_cpu_freq -r
Current Frequency: 1000mhz

Ofcourse I don't modify this inside the code.

Just so you can get an idea of the difference,

////// OUTSIDE ARDUPILOT COMPILING ROUTINE
root@beaglebone:/var/lib/cloud9/Printf# chrt -r 99 ./Printf
Initializing Control System...
MPC Timing = 14.807334

///// INSIDE ARDUPILOT COMPING ROUTINE
root@beaglebone:/home/debian/ardupilot/build/blue/examples# chrt -r 99 ./Printf
Initializing Control System...
MPC Timing = 8.694375

So it is almost twice. I do need it.

Regards,
Oscar