Following test program:
import time
import marshal
try:
import cPickle as pickle
str_ = unicode
except:
import pickle
str_ = str
def TestPrc(rd):
d = rd.recv()
print("OK")
def TestPrc2(rd):
d = pickle.loads(rd.recv())
print("OK")
if __name__ == "__main__":
from multiprocessing import freeze_support, Process, Pipe
freeze_support()
d = { str_(x) : u"Hello World" + str_(x + 1) for x in range(1000000) }
wr, rd = Pipe()
p = Process(target = TestPrc, args = ( rd, ))
p.start()
t1 = time.time()
wr.send(d)
print("#1", time.time() - t1)
p.join()
print("#2", time.time() - t1)
p = Process(target = TestPrc2, args = ( rd, ))
p.start()
t1 = time.time()
wr.send(pickle.dumps(d, pickle.HIGHEST_PROTOCOL))
print("#3", time.time() - t1)
p.join()
print("#4", time.time() - t1)
I get the following results:
Python 2.7:
('#1', 0.33500003814697266)
OK
('#2', 0.7890000343322754)
('#3', 0.36300015449523926)
OK
('#4', 0.8059999942779541)
Python 3.4:
#1 0.7770781517028809
OK
#2 1.4451451301574707
#3 0.7410738468170166
OK
#4 1.3691368103027344
Python 3.6:
#1 0.681999921798706
OK
#2 1.1500000953674316
#3 0.6549999713897705
OK
#4 1.1089999675750732
The results show that in Python 3 it is faster to do the (un-)pickling in the
Python code. I would expect to have no real performance difference, or at least
the more straight forward way to send Python objects directly to be a bit
faster, as it is in Python 2.
Some other interesting results from this example:
- Python 2 is much faster
- At least Python 3.6 is much faster than Python 3.4
Regards,
Martin
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