ctypes slow

gistfile1.py

import ctypes, time, array

count = 64 ** 2 * 24

t0 = time.time()
for x in range(100):
	v = [0] * count
t1 = time.time()
print "python list", (t1-t0)*10, 'ms'

t2 = time.time()
for x in range(100):
	cv = (ctypes.c_float * count)(*v) 
t3 = time.time()
print "ctypes constructor", (t3-t2)*10, 'ms'

t4 = time.time()
cv = (ctypes.c_float * count)()
for x in range(100):
	for v in range(count):
		cv[v] = 0.0
t5 = time.time()
print "ctypes setitem", (t5-t4)*10, 'ms'

t6 = time.time()
cv = [0] * count
for x in range(100):
	for v in range(count):
		cv[v] = 0.0
t7 = time.time()
print "list setitem", (t7-t6)*10, 'ms'


t8 = time.time()
for x in range(100):
	cv = array.array('f', [0] * count)
t9 = time.time()
print "array constructor", (t9-t8)*10, 'ms'

"""
Results:
(Windows 7)

$ pypy ./gistfile1.py
python list 0.350000858307 ms
ctypes constructor 50.720000267 ms
ctypes setitem 44.5799994469 ms
list setitem 0.95999956131 ms
array constructor 6.07000112534 ms

$ python ./gistfile1.py
python list 0.490019321442 ms
ctypes constructor 22.9613208771 ms
ctypes setitem 19.2010879517 ms
list setitem 15.6108999252 ms
array constructor 5.01028060913 ms
"""