Can Go really be that much faster than Python?

Question

I think I may have implemented this incorrectly because the results do not make sense. I have a Go program that counts to 1000000000:

package main

import (
             


        

Answer 1

@troq

I'm a little late to the party but I'd say the answer is yes and no. As @gnibbler pointed out, CPython is slower in the simple implementation but pypy is jit compiled for much faster code when you need it.

If you're doing numeric processing with CPython most will do it with numpy resulting in fast operations on arrays and matrices. Recently I've been doing a lot with numba which allows you to add a simple wrapper to your code. For this one I just added @njit to a function incALot() which runs your code above.

On my machine CPython takes 61 seconds, but with the numba wrapper it takes 7.2 microseconds which will be similar to C and maybe faster than Go. Thats an 8 million times speedup.

So, in Python, if things with numbers seem a bit slow, there are tools to address it - and you still get Python's programmer productivity and the REPL.

def incALot(y):
    x = 0
    while x < y:
        x += 1

@njit('i8(i8)')
def nbIncALot(y):
    x = 0
    while x < y:
        x += 1
    return x

size = 1000000000
start = time.time()
incALot(size)
t1 = time.time() - start
start = time.time()
x = nbIncALot(size)
t2 = time.time() - start
print('CPython3 takes %.3fs, Numba takes %.9fs' %(t1, t2))
print('Speedup is: %.1f' % (t1/t2))
print('Just Checking:', x)

CPython3 takes 58.958s, Numba takes 0.000007153s
Speedup is: 8242982.2
Just Checking: 1000000000