I don't think ceval is the issue here.

> the code has changed a great deal with regards to xmlrpc 
I am not sure to understand what you mean: xmlrpc is mostly written in
python code.

ceval.c is the place where the interpreter executes python code.
PyEval_EvalFrame is the loop that reads and dispatches each python
instruction.
Of course this function is time-critical, but the problem probably is
that too many python code is executed.

I suggest you to use the python-level profiler:
http://docs.python.org/lib/profile-instant.html
This may reveal some interesting things in the xmlrpclib module.