[Qgis-developer] Poor asynchronous performance of Python threads?

[Charlie Sharpsteen]

Hello list,

I have been playing around with the development branch of IPython (0.11-dev)
as they have built a PyQt-based console that supports all sorts of awesome
features like tab-completion, paged browsing of function code and
docstrings, and Pygments-powered syntax highlighting in addition to the
normal IPython goodness.  I slapped together a quick plugin that adds an
IPython-based console to QGIS.  The code is available at:

    https://github.com/Sharpie/qgis-ipython

To use it, you will need to install ZeroMQ, pyzmq, pygments and the dev
version of IPython from:

    https://github.com/ipython/ipython

The console fires up allright, but unfortunately very, very, very slow.
 There is about ~1-2 seconds of lag between invoking a command
and receiving a response.  For comparison, I threw together a minimal PyQGIS
application that also uses the IPython console:

    https://gist.github.com/817914

The PyQGIS version is very snappy and there is no lag.  I suspect the
difference is due to the PyQt widget is talking to an external IPython
process through ZeroMQ.  When a command is executed, the console sends a
message and then a Python thread waits for the response.  With PyQGIS,
Python is controlling the execution of the entire application.  However,
when the console is used as a plugin it is running in an embedded
interpreter and it looks like QGIS takes a while to schedule the execution
of the Python threads.

Does anyone have any suggestions for solving or working around this issue?

-Charlie
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/qgis-developer/attachments/20110208/6d6c549b/attachment-0001.html