talks/2020-en-attendant-la-pycon-fr-perf.md

Performance

• cProfile
• pstats

::: notes

Se présenter.

Le code

def main():
    already_checked = []
    while True:
        c = "".join(choice(ascii_letters) for _ in range(10))
        if c in already_checked: continue
        already_checked.append(c)
        digest = sha512(
            (c + args.string).encode("UTF-8")).hexdigest()
        if digest.startswith(args.sha_prefix):
            print(f"sha512({c} + {args.string}) = {digest}")
            sys.exit(0)
        print("Searching")

Premiers tests

$ time python perf.py AFPy 00
Searching
[...]
Searching
Found: sha512(5NX3dB0BrO + AFPy) = 00…

real 0m0.048s
user 0m0.040s
sys 0m0.008s

Premiers tests

$ time python perf.py AFPy 000
Searching
[...]
Searching
Found: sha512(UYb0z6nac1 + AFPy) = 000…

real 0m2.797s
user 0m2.773s
sys 0m0.024s

Premiers tests

$ time python perf.py AFPy 0000
Searching
[...]
Searching
Found: sha512(dX0oAzvOmm + AFPy) = 0000…

real 0m16.381s
user 0m16.375s
sys 0m0.004s

C'est long mais ça passe …

Premiers tests

$ time python perf.py AFPy 00000
Searching
[...]
Searching
Searching
Searching
Searching

Bon, on a un sushi.

cProfile

$ python -m cProfile -o prof perf.py AFPy 0000

pstats

$ python -m pstats prof
Welcome to the profile statistics browser.
prof% sort cumulative
prof% stats 10

pstats

ncalls  cumtime  percall filename:lineno(function)
  12/1   17.007   17.007 {built-in method builtins.exec}
     1   17.007   17.007 /tmp/perf.py:1(<module>)
     1   16.996   16.996 /tmp/perf.py:20(main)
 36429    0.869    0.000 {method 'join' of 'str' objects}

snakeviz

$ pip install snakeviz
Collecting snakeviz
  Using cached snakeviz-2.1.0-py2.py3-none-any.whl (282 kB)
Collecting tornado>=2.0
  Using cached tornado-6.1-cp39-cp39-manylinux2010_x86_64.whl (427 kB)
Installing collected packages: tornado, snakeviz
Successfully installed snakeviz-2.1.0 tornado-6.1

snakeviz

$ snakeviz prof

snakeviz

vprof

$ pip install vprof
Collecting vprof
  Using cached vprof-0.38-py3-none-any.whl (319 kB)
Collecting psutil>=3
  Using cached psutil-5.7.3-cp39-cp39d-linux_x86_64.whl
Installing collected packages: psutil, vprof
Successfully installed psutil-5.7.3 vprof-0.38

vprof

$ vprof -c h "perf.py AFPy 0000"

vprof

Le code, v1

def main():
    already_checked = []
    while True:
        c = "".join(choice(ascii_letters) for _ in range(10))
        if c in already_checked: continue
        already_checked.append(c)
        digest = sha512(
            (c + args.string).encode("UTF-8")).hexdigest()
        if digest.startswith(args.sha_prefix):
            print(f"sha512({c} + {args.string}) = {digest}")
            sys.exit(0)
        print("Searching")

Le code, v2

def main():
    already_checked = set()
    while True:
        c = "".join(choice(ascii_letters) for _ in range(10))
        if c in already_checked: continue
        already_checked.add(c)
        digest = sha512(
            (c + args.string).encode("UTF-8")).hexdigest()
        if digest.startswith(args.sha_prefix):
            print(f"sha512({c} + {args.string}) = {digest}")
            sys.exit(0)
        print("Searching")

Les perfs

$ hyperfine 'python perf.py AFPy 00000'

• v1 : ∞
• v2 (set) : 23 s ± 23 s

::: notes

Il existe aussi pyperf: https://github.com/psf/pyperf

cProfile + pstats

$ python -m cProfile -o prof perf.py AFPy 0000
$ python -m pstats prof

cProfile + pstats

  ncalls  cumtime  percall filename:lineno(function)
    12/1    1.156    1.156 {built-in method builtins.exec}
       1    1.156    1.156 perf.py:1(<module>)
       1    1.143    1.143 perf.py:35(main)
   34215    0.771    0.000 {method 'join' of 'str' objects}
  371647    0.681    0.000 perf.py:39(<genexpr>)
  337860    0.526    0.000 /python3.9/random.py(choice)
  337860    0.283    0.000 /python3.9/random.py(randbelow)
   33786    0.134    0.000 built-in method print
  372745    0.037    0.000 method 'getrandbits' of Random'
   33786    0.037    0.000 method 'hexdigest' of hashlib

snakeviz

$ snakeviz prof

snakeviz

Le code, v2

def main():
    already_checked = set()
    while True:
        c = "".join(choice(ascii_letters) for _ in range(10))
        if c in already_checked: continue
        already_checked.add(c)
        digest = sha512(
            (c + args.string).encode("UTF-8")).hexdigest()
        if digest.startswith(args.sha_prefix):
            print(f"sha512({c} + {args.string}) = {digest}")
            sys.exit(0)
        print("Searching")

Le code, v3

def main():
    already_checked = set()
    while True:
        c = "".join(choices(ascii_letters, k=10))
        if c in already_checked: continue
        already_checked.add(c)
        digest = sha512(
            (c + args.string).encode("UTF-8")).hexdigest()
        if digest.startswith(args.sha_prefix):
            print(f"sha512({c} + {args.string}) = {digest}")
            sys.exit(0)
        print("Searching")

Les perfs

$ hyperfine 'python perf.py AFPy 00000'

• v1 : ∞
• v2 (set) : 23 s ± 23 s
• v3 (choices): 8.591 s ± 6.525 s

snakeviz

Le code, v4

def main():
    already_checked = set()
    for c in product(ascii_letters, repeat=10):
        c = "".join(c)
        if c in already_checked: continue
        already_checked.add(c)
        digest = sha512(
            (c + args.string).encode("UTF-8")).hexdigest()
        if digest.startswith(args.sha_prefix):
            print(f"sha512({c} + {args.string}) = {digest}")
            sys.exit(0)
        print("Searching")

Les perfs

$ hyperfine 'python perf.py AFPy 00000'

• v1 : ∞
• v2 (set) : 23 s ± 23 s
• v3 (choices): 8.591 s ± 6.525 s
• v4 (deterministic) : 3.900 s ± 0.121 s

snakeviz

Le code, v5

def main():
    already_checked = set()
    for c in product(ascii_letters, repeat=10):
        c = "".join(c)
        if c in already_checked: continue
        already_checked.add(c)
        digest = sha512(
            (c + args.string).encode("UTF-8")).hexdigest()
        if digest.startswith(args.sha_prefix):
            print(f"sha512({c} + {args.string}) = {digest}")
            sys.exit(0)
        # print("Searching")

Les perfs

$ hyperfine 'python perf.py AFPy 00000'

• v1 : ∞
• v2 (set) : 23 s ± 23 s
• v3 (choices): 8.591 s ± 6.525 s
• v4 (deterministic) : 3.900 s ± 0.121 s
• v5 (print) : 3.120 s ± 0.062 s

Snakeviz

Il reste du hexdigest, du encode, et du join.

vprof

Ligne 26 et 28 !?

Le code, v6

def main():
    for c in product(ascii_letters, repeat=10):
        c = "".join(c)
        digest = sha512(
            (c + args.string).encode("UTF-8")).hexdigest()
        if digest.startswith(args.sha_prefix):
            print(f"sha512({c} + {args.string}) = {digest}")
            sys.exit(0)

Snakeviz

Il reste du hexdigest, du encode, et du join.

Le code, v7

def main():
    string = args.string.encode("UTF-8")
    pool = ascii_letters.encode("UTF-8")
    for c in product(pool, repeat=10):
        digest = sha512(bytes(c) + string).hexdigest()
        if digest.startswith(args.sha_prefix):
            print(f"sha512({bytes(c)} + {args.string}) = "
                  f"{digest}")
            sys.exit(0)

Les perfs

$ hyperfine 'python perf.py AFPy 00000'

• v1 : ∞
• v2 (set) : 23 s ± 23 s
• v3 (choices): 8.591 s ± 6.525 s
• v4 (deterministic) : 3.900 s ± 0.121 s
• v5 (print) : 3.120 s ± 0.062 s
• v6 (dead code): 2.844 s ± 0.059 s
• v7 (bytes) : 1.837 s ± 0.067 s

Encore plus d'expériences

• pypy: 3.8s
• python: 1.8s
• cython (hashlib) 1.3s
• cython (crypto) 0.8s
• c: 0.3s