How do I ensure that a Python while-loop takes a particular amount of time to run?

Question

I\'m reading serial data with a while loop. However, I have no control over the sample rate.

The code itself seems to take 0.2s to run, so I know I won\'t be able to

Answer 1

An rather elegant method is you're working on UNIX : use the signal library

The code :

import signal


def _handle_timeout():
    print "timeout hit" # Do nothing here

def second(count):
    signal.signal(signal.SIGALRM, _handle_timeout)
    signal.alarm(1)
    try:
        count += 1 # put your function here
        signal.pause()

    finally:
        signal.alarm(0)
        return count


if __name__ == '__main__':

    count = 0
    count = second(count)
    count = second(count)
    count = second(count)
    count = second(count)
    count = second(count)

    print count

And the timing :

 georgesl@cleese:~/Bureau$ time python timer.py
 5

 real   0m5.081s
 user   0m0.068s
 sys    0m0.004s

Two caveats though : it only works on *nix, and it is not multithread-safe.