Load Testing

Server Side

Legacy Tests - https://github.com/edx/load-tests (internal-only repo)

Current Tests - https://github.com/edx/edx-load-tests

Framework - https://github.com/locustio/locust(used currently in edx-load-tests. We also have a fork, and some legacy JMeter scripts)

How to Run Load Tests

Client Side (Browser)

Framework - http://www.sitespeed.io/ (Install via npm)

Useful add-in - https://github.com/edx/edx-sitespeed (for logged-in sessions)

Network throttling tools: Network Link Conditioner, tc (ubuntu native), wondersharper (which does not work on virtual machines), etc

Monitoring in Environments

New Relic

https://rpm.newrelic.com/accounts/88178/browser/1588430

Profiling

PyInstrument

PyInstrument can be helpful because of the way it writes output data as a call tree. More info here:

https://github.com/joerick/pyinstrument

Example of a profile using pyinstrument, writing output to a file:

from pyinstrument import Profiler
profiler = Profiler(use_signal=False)
profiler.start()
# Do stuff here
profiler.stop()
 
# write profile data to file
with open('my.log', 'w') as f:
  f.write(profiler.output_text())

SnakeViz

Here are the steps to profile your python code with cProfile and then view the results using SnakeViz.

1. export VAGRANT_X11=1
2. vagrant ssh
3. First time only: Install SnakeViz. Please update this document with the steps you used if you do it.
4. sudo su edxapp
5. Add the following to the code that you want to profile
  from openedx.core.djangoapps.performance.utils import collect_profile with collect_profile: <python_code_to_profile>
6. Then use SnakeViz by issuing:
  1. snakeviz DIRECTORY/FILE_NAME.profile

Tips

When profiling locally, disable features that would affect performance numbers. For instance, the following can be set in the a local [lms/cms]/envs/private.py file:

from .common import INSTALLED_APPS, MIDDLEWARE_CLASSES, FEATURES
def tuple_without(source_tuple, exclusion_list):
    """Return new tuple excluding any entries in the exclusion list. Needed because tuples
    are immutable. Order preserved."""
    return tuple([i for i in source_tuple if i not in exclusion_list])
INSTALLED_APPS = tuple_without(INSTALLED_APPS, ['debug_toolbar', 'debug_toolbar_mongo'])
MIDDLEWARE_CLASSES = tuple_without(MIDDLEWARE_CLASSES, [
    'django_comment_client.utils.QueryCountDebugMiddleware',
    'debug_toolbar.middleware.DebugToolbarMiddleware',
])
DEBUG_TOOLBAR_MONGO_STACKTRACES = False

import contracts
contracts.disable_all()

Performance tools