def loadavg () :
    """ Get load average from /proc/loadavg

        The first three fields in this file are load average figures
        giving the number of jobs in the run queue (state R) or
        waiting for disk I/O (state D) averaged over 1, 5, and 15
        minutes. They are the same as the load average numbers given
        by uptime(1) and other programs.

        We use the one-minute average.
    """
    with open ('/proc/loadavg') as f :
        l = f.readline ()
        a1m = float (l.split () [0])
    return a1m