Pi B+ or Pi 2 - CPU 93% ???

Hi All,

I added a second PiAware for systems development: upgraded antenna test, may be some coding for various things. FA immediately detected it - great! I received an anomaly report stating that the Pi B+ is at 93% CPU load and to consider upgrading to a Pi 2. Two questions come to mind:

  • Will the software run on both Arm 6 and Arm 7 CPU? I know there two versions on Raspian one for each CPU type. Are there two different versions of PiAware one for Arm 6 and one for Arm 7?

  • Do I really need a P2 for CPU load or is that message just a symptom or glitch of adding a second PiAware under one account? seems acutely coincidental… (???).


Could it be anything to do with the extra workload trying to correlate data for MLAT from a nearby receiver (i.e. your other receiver) ?
You could turn off MLAT to see if that is indeed a factor.

Yes, both systems have MLAT enabled. Oddly the error went away. Has not reoccurred as yet. I sort of eyeball CPU activity on the 1st PiAware by flicker an the Pi red LED. I rarely see any. Not sure if the LED indicates read/write on the micro SD card. Do you know if that’s the case? Do you know Linux command for CPU activity? Maybe I can monitor during peak time.

Thanks atari400!

Try “top” or “htop” command for seeing CPU load per process.

I may be wrong but I’m fairly sure the red LED flickering is down to power supply issues.

The sdcard image and packages will work on both. There are different kernels / firmware for the different models but raspbian does the right thing here automatically. The binaries themselves are built for arm6 and will work on arm7.

Yes, the red LED means your power supply is dropping out.

For the B+, you can safely overclock it.

Need to listen to the master theme. Maybe he made a mistake with the color of the led? The LEDs are labeled. If flickering led PWR the system would be unable to work at all. A frequent flickering of the led treatment to the SD card suggests that you use a slow card (not 10th class) or system errors occur, which are constantly written to the log file and due to the slow SD card delays write operations.

Thanks very much! I bought a B+ specifically because of the Arm 6 CPU thinking that PiAware would not run on an Arm 7. I will return and upgrade to the Pi 2. The operational, always on, PiAware receiver will get the Pi 2.

Thanks r2zac!! I ran ‘top’ through an ssh session. Looks like 30% to 33% CPU usage tracking 20 aircraft. 93% looks like an error or fluke of some kind. I will keep an eye on it. Really great knowing CPU usage!

As far as swapping my 1st PiAware from Pi B+ to a Pi 2, I am bit reluctant since my stats are rising. Its ranking is 2318. I will swap the system development PiAware from Pi B+ to Pi 2 however.