def pax_to_human_time(num):
    """Converts a pax time to a human-readable representation"""
    for x in ['ns', 'us', 'ms', 's', 'ks', 'Ms', 'G', 'T']:
        if num < 1000.0:
            return "%3.3f %s" % (num, x)
        num /= 1000.0
    return "%3.1f %s" % (num, 's')