pyprof progresses

It has been a week since the beginning of pyprof. The project is progressing well.

The code is in the usual place:
https://fepy.svn.sourceforge.net/svnroot/fepy/trunk/pyprof/

There are some Makefile updates. Some variables are now defined at the top of the file. You may want to change the path to Mono, Python, and IronPython there.

I wrote a call tracer in pure Python using sys.setprofile which should print the essentially same output as pyprof. The filename is prof.py, and you can type "make testpy" to see its output. Compare the output with one from "make test".

You can type "make test.out" to update the reference output. This file is quite long, as I swapped the sample script to one using nntplib from the Python standard library. The script connects to Gmane and print the description of comp.lang.python newsgroup.

Some new features of the call tracer includes obvious ones like printing method leave events, and indenting messages to show the call depth. After some refactoring, logic for filtering non-Python assemblies and IronPython-internal methods now live in the separate function. I plan to split them to the separate file actually.

IronPython-internal TryGetExtraValue calls are now ignored. This was obvious once I moved to profiling real programs.

In the last post, I wrote that test output assumes you have blank site.py. Then I remembered that Python has a command line option -S to disable importing of site.py. Unfortunately, this revealed a bug in IronPython. I reported the bug to the IronPython mailing list and wrote a patch to fix it.

Development of pyprof also revealed a bug in the Mono runtime. When the method is left by throwing an exception, the profiler was not notified about the event. This is problematic, because the Python Library Reference specifies about sys.setprofile (link) that "the return event is reported even when an exception has been set".

I reported the bug to the Mono mailing list and subsequently wrote a 4-line patch. That patch actually took 4 hours to come with (a line per an hour :-), but I learned a lot in the process. Miguel de Icaza promptly applied the patch for me.

Now I need to look at the profiling API for Microsoft .NET runtime, as demanded by Michael Foord.