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timeit: start autorange with 1 iteration, not 10 

Issue #28240: timeit autorange now uses a single loop iteration if the
benchmark takes less than 10 seconds, instead of 10 iterations.

"python3 -m timeit -s 'import time' 'time.sleep(1)'" now takes 4 seconds
instead of 40 seconds.
This commit is contained in:
Victor Stinner 2016-10-18 17:06:56 +02:00
parent bf9655854b
commit f8fb82cd25
3 changed files with 32 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
Lib/test/test_timeit.py
View File

@ -226,7 +226,7 @@ class TestTimeit(unittest.TestCase):
t.print_exc(s)
self.assert_exc_string(s.getvalue(), 'ZeroDivisionError')
MAIN_DEFAULT_OUTPUT = "10 loops, best of 3: 1 sec per loop\n"
MAIN_DEFAULT_OUTPUT = "1 loop, best of 3: 1 sec per loop\n"
def run_main(self, seconds_per_increment=1.0, switches=None, timer=None):
if timer is None:
@ -252,7 +252,7 @@ class TestTimeit(unittest.TestCase):
def test_main_seconds(self):
s = self.run_main(seconds_per_increment=5.5)
self.assertEqual(s, "10 loops, best of 3: 5.5 sec per loop\n")
self.assertEqual(s, "1 loop, best of 3: 5.5 sec per loop\n")
def test_main_milliseconds(self):
s = self.run_main(seconds_per_increment=0.0055)
@ -280,11 +280,11 @@ class TestTimeit(unittest.TestCase):
def test_main_fixed_reps(self):
s = self.run_main(seconds_per_increment=60.0, switches=['-r9'])
self.assertEqual(s, "10 loops, best of 9: 60 sec per loop\n")
self.assertEqual(s, "1 loop, best of 9: 60 sec per loop\n")
def test_main_negative_reps(self):
s = self.run_main(seconds_per_increment=60.0, switches=['-r-5'])
self.assertEqual(s, "10 loops, best of 1: 60 sec per loop\n")
self.assertEqual(s, "1 loop, best of 1: 60 sec per loop\n")
@unittest.skipIf(sys.flags.optimize >= 2, "need __doc__")
def test_main_help(self):
@ -308,14 +308,15 @@ class TestTimeit(unittest.TestCase):
def test_main_verbose(self):
s = self.run_main(switches=['-v'])
self.assertEqual(s, dedent("""\
10 loops -> 10 secs
raw times: 10 10 10
10 loops, best of 3: 1 sec per loop
1 loop -> 1 secs
raw times: 1 1 1
1 loop, best of 3: 1 sec per loop
"""))
def test_main_very_verbose(self):
s = self.run_main(seconds_per_increment=0.000050, switches=['-vv'])
self.assertEqual(s, dedent("""\
1 loop -> 5e-05 secs
10 loops -> 0.0005 secs
100 loops -> 0.005 secs
1000 loops -> 0.05 secs
@ -328,15 +329,15 @@ class TestTimeit(unittest.TestCase):
unit_sec = self.run_main(seconds_per_increment=0.002,
switches=['-u', 'sec'])
self.assertEqual(unit_sec,
"1000 loops, best of 3: 0.002 sec per loop\n")
"100 loops, best of 3: 0.002 sec per loop\n")
unit_msec = self.run_main(seconds_per_increment=0.002,
switches=['-u', 'msec'])
self.assertEqual(unit_msec,
"1000 loops, best of 3: 2 msec per loop\n")
"100 loops, best of 3: 2 msec per loop\n")
unit_usec = self.run_main(seconds_per_increment=0.002,
switches=['-u', 'usec'])
self.assertEqual(unit_usec,
"1000 loops, best of 3: 2e+03 usec per loop\n")
"100 loops, best of 3: 2e+03 usec per loop\n")
# Test invalid unit input
with captured_stderr() as error_stringio:
invalid = self.run_main(seconds_per_increment=0.002,
@ -354,8 +355,8 @@ class TestTimeit(unittest.TestCase):
s = self.run_main(switches=['-n1', '1/0'])
self.assert_exc_string(error_stringio.getvalue(), 'ZeroDivisionError')
def autorange(self, callback=None):
timer = FakeTimer(seconds_per_increment=0.001)
def autorange(self, seconds_per_increment=0.001, callback=None):
timer = FakeTimer(seconds_per_increment=seconds_per_increment)
t = timeit.Timer(stmt=self.fake_stmt, setup=self.fake_setup, timer=timer)
return t.autorange(callback)
@ -364,14 +365,20 @@ class TestTimeit(unittest.TestCase):
self.assertEqual(num_loops, 1000)
self.assertEqual(time_taken, 1.0)
def test_autorange_second(self):
num_loops, time_taken = self.autorange(seconds_per_increment=1.0)
self.assertEqual(num_loops, 1)
self.assertEqual(time_taken, 1.0)
def test_autorange_with_callback(self):
def callback(a, b):
print("{} {:.3f}".format(a, b))
with captured_stdout() as s:
num_loops, time_taken = self.autorange(callback)
num_loops, time_taken = self.autorange(callback=callback)
self.assertEqual(num_loops, 1000)
self.assertEqual(time_taken, 1.0)
expected = ('10 0.010\n'
expected = ('1 0.001\n'
'10 0.010\n'
'100 0.100\n'
'1000 1.000\n')
self.assertEqual(s.getvalue(), expected)

10
Lib/timeit.py
View File

@ -218,7 +218,7 @@ class Timer:
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):
for i in range(0, 10):
number = 10**i
time_taken = self.timeit(number)
if callback:
@ -318,8 +318,10 @@ def main(args=None, *, _wrap_timer=None):
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))
msg = "{num} loop{s} -> {secs:.{prec}g} secs"
plural = (number != 1)
print(msg.format(num=number, s='s' if plural else '',
secs=time_taken, prec=precision))
try:
number, _ = t.autorange(callback)
except:
@ -333,7 +335,7 @@ def main(args=None, *, _wrap_timer=None):
best = min(r)
if verbose:
print("raw times:", " ".join(["%.*g" % (precision, x) for x in r]))
print("%d loops," % number, end=' ')
print("%d loop%s," % (number, 's' if number != 1 else ''), end=' ')
usec = best * 1e6 / number
if time_unit is not None:
scale = units[time_unit]

5
Misc/NEWS
View File

@ -88,6 +88,11 @@ Core and Builtins
Library
-------
- Issue #28240: timeit autorange now uses a single loop iteration if the
benchmark takes less than 10 seconds, instead of 10 iterations.
"python3 -m timeit -s 'import time' 'time.sleep(1)'" now takes 4 seconds
instead of 40 seconds.
- Distutils.sdist now looks for README and setup.py files with case
sensitivity. This behavior matches that found in Setuptools 6.0 and
later. See `setuptools 100