diff options
Diffstat (limited to 'Lib/timeit.py')
| -rw-r--r--[-rwxr-xr-x] | Lib/timeit.py | 73 |
1 files changed, 49 insertions, 24 deletions
diff --git a/Lib/timeit.py b/Lib/timeit.py index 2de88f7271..2770efa35a 100755..100644 --- a/Lib/timeit.py +++ b/Lib/timeit.py @@ -207,6 +207,26 @@ class Timer: r.append(t) return r + def autorange(self, callback=None): + """Return the number of loops so that total time >= 0.2. + + Calls the timeit method with *number* set to successive powers of + ten (10, 100, 1000, ...) up to a maximum of one billion, until + the time taken is at least 0.2 second, or the maximum is reached. + Returns ``(number, time_taken)``. + + If *callback* is given and is not None, it will be called after + each trial with two arguments: ``callback(number, time_taken)``. + """ + for i in range(1, 10): + number = 10**i + time_taken = self.timeit(number) + if callback: + callback(number, time_taken) + if time_taken >= 0.2: + break + return (number, time_taken) + def timeit(stmt="pass", setup="pass", timer=default_timer, number=default_number, globals=None): """Convenience function to create Timer object and call timeit method.""" @@ -295,17 +315,16 @@ def main(args=None, *, _wrap_timer=None): t = Timer(stmt, setup, timer) if number == 0: # determine number so that 0.2 <= total time < 2.0 - for i in range(1, 10): - number = 10**i - try: - x = t.timeit(number) - except: - t.print_exc() - return 1 - if verbose: - print("%d loops -> %.*g secs" % (number, precision, x)) - if x >= 0.2: - break + callback = None + if verbose: + def callback(number, time_taken): + msg = "{num} loops -> {secs:.{prec}g} secs" + print(msg.format(num=number, secs=time_taken, prec=precision)) + try: + number, _ = t.autorange(callback) + except: + t.print_exc() + return 1 try: r = t.repeat(repeat, number) except: @@ -317,20 +336,26 @@ def main(args=None, *, _wrap_timer=None): print("%d loops," % number, end=' ') usec = best * 1e6 / number if time_unit is not None: - print("best of %d: %.*g %s per loop" % (repeat, precision, - usec/units[time_unit], time_unit)) + scale = units[time_unit] else: - if usec < 1000: - print("best of %d: %.*g usec per loop" % (repeat, precision, usec)) - else: - msec = usec / 1000 - if msec < 1000: - print("best of %d: %.*g msec per loop" % (repeat, - precision, msec)) - else: - sec = msec / 1000 - print("best of %d: %.*g sec per loop" % (repeat, - precision, sec)) + scales = [(scale, unit) for unit, scale in units.items()] + scales.sort(reverse=True) + for scale, time_unit in scales: + if usec >= scale: + break + print("best of %d: %.*g %s per loop" % (repeat, precision, + usec/scale, time_unit)) + best = min(r) + usec = best * 1e6 / number + worst = max(r) + if worst >= best * 4: + usec = worst * 1e6 / number + import warnings + warnings.warn_explicit( + "The test results are likely unreliable. The worst\n" + "time (%.*g %s) was more than four times slower than the best time." % + (precision, usec/scale, time_unit), + UserWarning, '', 0) return None if __name__ == "__main__": |