How profilers work - deterministic approach

det_prof.py

def is_prime(n):
    for i in range(2, n):
        if n % i == 0:
            return False
    return True

def sum_of_digits(n):
    s = 0
    while n:
        s += n % 10
        n //= 10
    return s

def get_primes(n):
    primes = []
    candidate = 2
    while len(primes) < n:
        if is_prime(candidate) and sum_of_digits(candidate) % 2 == 0:
            primes.append(candidate)
        candidate += 1
    return primes

import time
start_time = time.time()
primes = get_primes(1000)
total_time = time.time() - start_time
print("Total time is %f s" % total_time)

# Decorator approach
def profile(func):
    def wrapper(*args, **kwargs):
        start_time = time.time()
        result = func(*args, **kwargs)
        print("Function %s run time is %f s" % (
            func.__name__, time.time() - start_time))
        return result
    return wrapper

# is_prime = profile(is_prime)
# get_n_primes = profile(get_primes)
# sum_of_digits = profile(sum_of_digits)
# primes = get_primes(1000)\

# Decorator with stats
def profile_stats(func):
    def wrapper(*args, **kwargs):
        start_time = time.time()
        # We need this small hack to keep things simple.
        caller = sys._getframe(1).f_code.co_name
        result = func(*args, **kwargs)
        stats[func.__name__][caller] += time.time() - start_time
        return result
    return wrapper

import sys
import time
from collections import defaultdict

is_prime = profile_stats(is_prime)
get_n_primes = profile_stats(get_primes)
sum_of_digits = profile_stats(sum_of_digits)
stats = defaultdict(lambda: defaultdict(float))

start_time = time.time()
primes = get_primes(1000)
end_time = time.time()

def print_summary(stats, total_time):
    print('Total runtime: %f s' % total_time)
    for f_name in stats:
        func_time = 0
        for caller in stats[f_name]:
            func_time += stats[f_name][caller]
            percentage = float(func_time) / total_time
        print('Function: %s, caller: %s, function run time: %f s, percentage: %f %%' % (
            f_name, caller, func_time, 100 * percentage))

print_summary(stats, end_time - start_time)