Return value while using cProfile

Question

I\'m trying to profile an instance method, so I\'ve done something like:

import cProfile

class Test():

    def __init__(self):
        pass

    def method         


        

Answer 1

I was struggling with the same problem and used a wrapper function to get over direct return values. Instead of

cP.runctx("a=foo()", globals(), locales())

I create a wrapper function

def wrapper(b):
  b.append(foo())

and profile the call to the wrapper function

b = []
cP.runctx("wrapper(b)", globals(), locals())
a = b[0]

extracting the result of foo's computation from the out param (b) afterwards.

Answer 2

An option for any arbitrary code:

import cProfile, pstats, sys
pr = cProfile.Profile()
pr.enable()

my_return_val = my_func(my_arg)

pr.disable()
ps = pstats.Stats(pr, stream=sys.stdout)
ps.print_stats()

Taken from https://docs.python.org/2/library/profile.html#profile.Profile

Answer 3

I think @detly the .runcall() is basically the best answer, but for completeness, I just wanted to take @ThomasH 's answer to be function independent:

def wrapper(b, f, *myargs, **mykwargs):
    try:
        b.append(f(*myargs, **mykwargs))
    except TypeError:
        print 'bad args passed to func.'

# Example run
def func(a, n):
    return n*a + 1

b = []
cProfile.runctx("wrapper(b, func, 3, n=1)", globals(), locals())
a = b[0]
print 'a, ', a

Answer 4

I created a decorator:

import cProfile
import functools
import pstats

def profile(func):

    @functools.wraps(func)
    def inner(*args, **kwargs):
        profiler = cProfile.Profile()
        profiler.enable()
        try:
            retval = func(*args, **kwargs)
        finally:
            profiler.disable()
            with open('profile.out', 'w') as profile_file:
                stats = pstats.Stats(profiler, stream=profile_file)
                stats.print_stats()
        return retval

    return inner

Decorate your function or method with it:

@profile
def somefunc(...):
   ...

Now that function will be profiled.

Alternatively, if you'd like the raw, unprocessed profile data (e.g. because you want to run the excellent graphical viewer RunSnakeRun on it), then:

import cProfile
import functools
import pstats

def profile(func):

    @functools.wraps(func)
    def inner(*args, **kwargs):
        profiler = cProfile.Profile()
        profiler.enable()
        try:
            retval = func(*args, **kwargs)
        finally:
            profiler.disable()
            profiler.dump_stats('profile.out')
        return retval

    return inner

This is a minor improvement on several of the other answers on this page.

Answer 5

I discovered that you can do this:

prof = cProfile.Profile()
retval = prof.runcall(self.method_actual, *args, **kwargs)
prof.dump_stats(datafn)

The downside is that it's undocumented.