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pythonprofilingcherrypymiddleware

Profiling CherryPy

I've been trying to start profiling my CherryPy webserver, but the documentation is lacking in detail in how this should be set up. I understand that I should be able to use cherrypy.lib.profiler as middleware to mount my initial server. Right now, I have code like the following:

server_app = ServerClass()
cherrypy.tree.mount(server_app, '/', '/path/to/config/file.cfg')
cherrypy.engine.start()
cherrypy.engine.block()

I want to mount the profiling middleware, and it seems that something like the following is required:

from cherrypy.lib import profiler

server_app = ServerClass()
server_cpapp = cherrypy.Application(server_app, '/', '/path/to/config/file.cfg')
server_profile_cpapp = profiler.make_app(server_cpapp, '/home/ken/tmp/cprofile', True)
#cherrypy.tree.mount(server_profile_cpapp)
cherrypy.tree.graft(server_profile_cpapp)

cherrypy.engine.start()
cherrypy.engine.block()

For some reason cherrypy.tree.mount doesn't work, but if I use cherrypy.tree.graft all seems to operate fine (I can make requests to the server as normal)

However, the above code generates a cp_0001.prof file under /home/ken/tmp/cprofile and I am not sure how to interpret it. I have tried using pyprof2calltree to read the data into KCacheGrind, but I get a parsing error. Does what I'm doing seem correct, and if so how do I interpret the output file?

Solution

  • It turns out that the profile files generated by CherryPy can be interpreted using the profiler.py script shipped as part of CherryPy. Simply run profiler.py in the <site-packages>/cherrypy/lib directory as follows:

    python profiler.py /directory/containing/prof/files 8080

    Then navigate to localhost:8080 in your browser and the profiling results for all .prof files in the target directory will be displayed in a simple text interface.

    I would still prefer to be able to export the results into a calltree to profile using KCacheGrind, but this seems to do for basic profiling.

    This is documented in the change log for v2.1 of CherryPy when the profiler was introduced (although the other details on that page describing how to set up the profiler has since become deprecated)