[etwist] Do not call repository's start_looping_tasks anymore and warn about this
We are about to drop this method from Repository class and replace it by a
blocking alternative. This is not compatible with how things currently work in
a Twisted server implementation. So do not start repository "looping tasks" in
Twisted server anymore and issue a warning about this.
If someone is interested in restoring the "all-in-one" behavior where the
repository runs within a Twisted server, they may start by implementing
repository looping tasks using a Twisted mechanism such as, e.g.,
http://twistedmatrix.com/documents/current/core/howto/time.html and eventually
provide the repository with a compatible scheduler instance so that is can
register its periodic tasks. At the moment, we lack resources to do this (and
maintain the Twisted server of CubicWeb in general).
Related to #17057223.
.. _profiling:
Profiling
=========
Profiling of requests by the pyramid debug toolbar can be a little restrictive
when a specific url needs thin profiling that includes the whole pyramid
dispatch.
Pyramid CubicWeb provides facilities to profile requests as a
:func:`wsgi middleware <cubicweb.pyramid.profile.wsgi_profile>`, and a few
views that facilitate profiling of basic features.
The views and the wsgi middleware are activated when the 'profile' option is
given. This can be done on the command line
(:option:`cubicweb-ctl pyramid --profile`) or in the :ref:`pyramid_settings`.
Views
-----
The following routes and corresponding views are provided when profiling is on:
- ``/_profile/ping``: Reply 'ping' without doing anything else. See also
:func:`cubicweb.pyramid.profile.ping`.
- ``/_profile/cnx``: Reply 'ping' after getting a cnx. See also
:func:`cubicweb.pyramid.profile.cnx`.
Typical Usage
-------------
Let's say we want to measure the cost of having a ``cnx``.
- Start the application with profile enabled:
.. code-block:: console
$ cubicweb-ctl pyramid --no-daemon --profile --profile-dump-every 100
- Use 'ab' or any other http benchmark tool to throw a lot of requests:
.. code-block:: console
$ ab -c 1 -n 100 http://localhost:8080/_profile/cnx
- Analyse the results. I personnaly fancy SnakeViz_:
.. code-block:: console
$ snakeviz program.prof
.. _SnakeViz: http://jiffyclub.github.io/snakeviz/