Hello all,
I make a simple code to measure process time on Raspberry pi 0,1,2,3 like:
* previous = rt_timer_read();*
* for (i=0; i<500; ++i)*
* {*
* bcm2835_gpio_write(TEST_PIN, HIGH);*
* bcm2835_gpio_write(TEST_PIN, LOW);*
* }*
* now = rt_timer_read();*
* process_time = (long) (now - previous);*
* if (process_time>worst_time)*
* worst_time=process_time;*
And I result after several hours running:
rpi process_time (us) worst_time (us)
0,1 ~100 115
2,3 ~90 373
It is clear that process time on rpi2,3 is shorter than that on rpi0,1 due
to higher speed CPU. However, I don't understand why worst case on rpi2,3
is much larger than that on rpi0,1. I have repeated this test on both
xenomai 2 and 3, kernel 4.1 and 4.9 (only xenomai 3 in this case) and with
different task priority, the result is quite consistent.
Does anyone have explanation and solution?
Thanks and regards,
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