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Ray Walker

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Thanks for this useful and needed explanations on top activity report!
I'm playing at the moment with iMX27 board and I want to profile the behaviour of the single app running on it. But, even after this article, I still can't figure out why I can have a 1-mn average load of 0 with a CPU% being about 6% (in this snapshot) but can go up to 53% and is most of the time in the STOP state!

Snapshot (3 hours run)
CPU: 4% usr 1% sys 0% nic 91% idle 0% io 2% irq 0% sirq
Load average: 0.00 0.00 0.00 2/53 18836
16857 1 root R 66436 53% 6%

N.B: the other process running was of course Top

if 6 to 53% of instructions executed by the CPU belongs to my app why the CPU seems not to be loaded and why the log still report an activity while the process is in a Stopped state?...

Here is a snapshot of the log activity of the App (matrix computation,for a kalman filter implementation, size might be in the worst case a 20 square matrix)

Calcul_v8: 230.0 ms; 95.8%; 1 Calls
Calcul_v8: 230.0 ms; 95.8%; 1 Calls
Calcul_v8: 240.0 ms; 96.0%; 1 Calls
Calcul_v8: 220.0 ms; 95.7%; 1 Calls

If anyone could have an explanation or just an idea, that will help a lot!

Johann