Version 10 (modified by 15 years ago) ( diff ) | ,
---|
Profiling Django
Profiling Specific Code
Python has several profiling modules, the least worst of which is the apparently unmaintained hotshot. It's better than the Profiler module for our purposes as it has simple 'start' and 'stop' methods, as well as a method that takes a callable and it's arguments.
I wrap views and other callables I want to examine in a decorator like this one:
import hotshot import os import time import settings try: PROFILE_LOG_BASE = settings.PROFILE_LOG_BASE except: PROFILE_LOG_BASE = "/tmp" def profile(log_file): """Profile some callable. This decorator uses the hotshot profiler to profile some callable (like a view function or method) and dumps the profile data somewhere sensible for later processing and examination. It takes one argument, the profile log name. If it's a relative path, it places it under the PROFILE_LOG_BASE. It also inserts a time stamp into the file name, such that 'my_view.prof' become 'my_view-20100211T170321.prof', where the time stamp is in UTC. This makes it easy to run and compare multiple trials. """ if not os.path.isabs(log_file): log_file = os.path.join(PROFILE_LOG_BASE, log_file) def _outer(f): def _inner(*args, **kwargs): # Add a timestamp to the profile output when the callable # is actually called. (base, ext) = os.path.splitext(log_file) base = base + "-" + time.strftime("%Y%m%dT%H%M%S", time.gmtime()) final_log_file = base + ext prof = hotshot.Profile(final_log_file) try: ret = prof.runcall(f, *args, **kwargs) finally: prof.close() return ret return _inner return _outer
Set a base path for storing profiling logs in your settings.py
using PROFILE_LOG_BASE
, then use it like this:
@profile("my_view.prof") def myview(request): ...
This will produces files of the form /path/to/logs/my_view-20100211T170321.prof
, so you can test your view under various input conditions and compare the results.
To actually examine the results, you'll need to use the hotshot.stats
module. A simple script like this:
#!/usr/bin/python import hotshot.stats import sys stats = hotshot.stats.load(sys.argv[1]) #stats.strip_dirs() stats.sort_stats('time', 'calls') stats.print_stats(20)
(stats.strip_dirs()
results in a more compact output, but I prefer to know which __init__.py
I'm dealing with.)
Here's some output from a profile of an authentication module I was having trouble with:
7986 function calls (7850 primitive calls) in 1.725 CPU seconds Ordered by: internal time, call count List reduced from 392 to 20 due to restriction <20> ncalls tottime percall cumtime percall filename:lineno(function) 2 1.570 0.785 1.570 0.785 /usr/local/lib/python2.5/django/db/backends/__init__.py:36(_commit) 15 0.043 0.003 0.043 0.003 /usr/local/lib/python2.5/linecache.py:68(updatecache) 1 0.020 0.020 0.027 0.027 /usr/local/lib/python2.5/django/contrib/auth/models.py:1(<module>) 12 0.014 0.001 0.030 0.002 /usr/local/lib/python2.5/django/utils/importlib.py:18(import_module) 1013 0.010 0.000 0.010 0.000 /usr/local/lib/python2.5/posixpath.py:56(join)
This shows that the culprit is the database commit code; while my queries where fast, actually committing the results to a SQLite database is causing me grief.
You can use gather_profile_stats.py in the Django distribution to aggregate the generated profile logs and open them with pstats.Stats
.
You can also examine the results with KCacheGrind by using it's hotshot2calltree
conversion scripts.
Profiling Everything
Middleware
Profiling Middleware and Extended Profiling Middleware print profile results for method, additionally groups results by files and by modules. Add the "&prof=" query parameter and you'll see the profiling results in your browser.
Unfortunately, these are both items on Django Snippets, so you should treat them as being untested abandonware, or, more charitably, example code.
django-profiling seems to be another variant of the profiling middleware, which declares itself superseded by django-logging, which declares itself unmaintained.
Profiling at the server
mod_python
django.core.handlers.profiler-hotshot
provides profiling support for Django when using mod_python
. TODO: describe how to use this.
Development Server
django-command-extensions provides a runprofileserver
command for running the development server using the hotshot library.
A similar solution for the internal development webserver: apply the included patch to django/core/management.py
and start Django with manage.py runserver
. Each request will create a .prof
file in your /tmp
directory.
WSGI
An alternative approach to using the built in development server is to run Django from a trivial WSGI server and profile that. For example, using wsgiref
:
from wsgiref.simple_server import make_server from django.core.handlers.wsgi import WSGIHandler httpd = make_server('', 8000, WSGIHandler()) httpd.serve_forever()
Run this using:
$ DJANGO_SETTINGS_MODULE=mysite.settings python myserver.py
To profile this run using cProfile (or profile):
$ DJANGO_SETTINGS_MODULE=mysite.settings python -m cProfile myserver.py
The default invocation will print the profile stats when you kill the server, it's probably more useful to write to a file and use pstats to read it:
$ DJANGO_SETTINGS_MODULE=mysite.settings python -m cProfile -o mysite.profile myserver.py ... lots of requests ... $ python >>> import pstats >>> s = pstats.Stats("mysite.profile") >>> s.sort_stats("time").print_stats(20)
Other Approaches
django-profile.py is a script that can be used to profile any Django-powered web-site and find how many SQL-queries are used per page, how heavy html-pages are, etc. See also django snippet 461.
Attachments (5)
-
runserver-profiler.diff
(1.3 KB
) - added by 19 years ago.
patch for management.py enables profiling for runserver
-
runserver-profiler2.diff
(1.2 KB
) - added by 18 years ago.
updated the patch against the latest revision
-
runserver-profiler2.2.diff
(1.2 KB
) - added by 18 years ago.
updated the patch against the latest revision and made the path configurable
-
profiler-cprofile.py
(547 bytes
) - added by 17 years ago.
Adapted profile handler to use cProfile module. Place in django/core/handlers and set PythonHandler in apache conf
-
runserver-profiler3.diff
(2.3 KB
) - added by 16 years ago.
New patch against r7569. Extend runserver command with '--profile' argument. Will run djangos development server with profiling output into systems temporary directory.
Download all attachments as: .zip