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


#1

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… (???).

Ted


#2

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.


#3

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!


#4

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


#5

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


#6

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.


#7

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

For the B+, you can safely overclock it.


#8

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.


#9

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.


#10

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.