ptime.py

#!/usr/bin/env python3

import ctypes
import datetime
import time
import multiprocessing
import itertools

libc = ctypes.CDLL('libc.so.6')

class struct_tm(ctypes.Structure):
    _fields_ = [
        ('tm_sec', ctypes.c_int),
        ('tm_min', ctypes.c_int),
        ('tm_hour', ctypes.c_int),
        ('tm_mday', ctypes.c_int),
        ('tm_mon', ctypes.c_int),
        ('tm_year', ctypes.c_int),
        ('tm_wday', ctypes.c_int),
        ('tm_yday', ctypes.c_int),
        ('tm_isdst', ctypes.c_int),
        ('tm_gmtoff', ctypes.c_long),
        ('tm_zone', ctypes.c_int)]

strptime_proto = ctypes.CFUNCTYPE(ctypes.c_char_p, ctypes.c_char_p,
                                                   ctypes.c_char_p,
                                                   ctypes.POINTER(struct_tm))

strptime = strptime_proto(('strptime', libc), ((1, 's'),
                                              (1, 'format'),
                                              (2, 'tm')))

def strptime_errcheck(result, func, args):
    if result is None:
        raise ValueError("strptime error.")
    return datetime.datetime(args[2].tm_year + 1900,
                             args[2].tm_mon,
                             args[2].tm_mday,
                             args[2].tm_hour,
                             args[2].tm_min,
                             args[2].tm_sec)

strptime.errcheck = strptime_errcheck

res = strptime(b"2001-11-12 18:31:01",
               b"%Y-%m-%d %H:%M:%S")

print('libc.strptime: parse "2001-11-12 18:31:01" against format "%Y-%m-%d %H:%M:%S":', res)

ts1 = time.time()
for _ in range(1000000):
    datetime.datetime.strptime("2001-11-12 18:31:01", "%Y-%m-%d %H:%M:%S")
print("datetime.strptime single thread:", time.time() - ts1)

ts2 = time.time()
for _ in range(1000000):
    res = strptime("2001-11-12 18:31:01".encode('ascii'),
                   "%Y-%m-%d %H:%M:%S".encode('ascii'))
print("libc.strptime single thread:", time.time() - ts2)

def T1(args):
    return datetime.datetime.strptime(*args)

def T2(args):
    return strptime(*args)

ts3 = time.time()
with multiprocessing.Pool(2) as p:
    it = p.imap(T1,
                itertools.repeat(("2001-11-12 18:31:01", "%Y-%m-%d %H:%M:%S"), 1000000),
                1000)
    for _ in it:
        pass
print("datetime.strptime MP:", time.time() - ts3)

ts4 = time.time()
with multiprocessing.Pool(2) as p:
    it = p.imap(T2,
                itertools.repeat((b"2001-11-12 18:31:01", b"%Y-%m-%d %H:%M:%S"), 1000000),
                1000)
    for _ in it:
        pass
print("libc.strptime MP:", time.time() - ts4)

Output (on Intel Pentium G4400, Fedora 30, Python 3.7):

[user@dt1 ~]$ ./ptime.py 
libc.strptime: parse "2001-11-12 18:31:01" against format "%Y-%m-%d %H:%M:%S": 2001-10-12 18:31:01
datetime.strptime single thread: 8.794349908828735
libc.strptime single thread: 1.8633613586425781
datetime.strptime MP: 6.025797128677368
libc.strptime MP: 1.9151949882507324