[Valgrind-users] Valgrind to profile CPython and Nuitka

[Kay H. <kay...@gm...>]

Hello there,

my name is Kay Hayen, I am the author of the Python compiler Nuitka 
(http://nuitka.net) and so far I have very successfully used Valgrind to 
analyse the performance of my created binaries in comparison to original 
CPython bytecode interpretation.

However, I am kind of set now, on creating a comparison tool. The user 
should be allowed to run his code with Nuitka and CPython, and it should 
be possible to compare the performance. I sort of promised this to my 
users during Europython this week.

For CPython, and partially Nuitka, where bytecode becomes evaluated, and 
effectively always in a Python frame, function or module, this is 
basically is just PyEval_CallFrame (or similar) on the C call stack, and 
as such totally impossible to associate to decode without looking at its 
arguments.

(For Nuitka, there also may be possibly inlining, which will not have a 
call made, but instead a debugging information change only. But lets 
ignore that, I probably need to solve that when presenting the data.)

I am therefore considering an improvement to callgrind, that would try 
to make it emit the Python function name, and the Python source file 
instead. Do you think that is possible, and can you give me pointers to 
inside the valgrind source distribution, what to change, where to hook?

Looking at callstack.c in callgrind directory, would it be possible to 
make direct accesses to the running binary to capture stuff from its 
data, from function arguments, or is that not possible?

Should this be possible, it would enable profiling of Python code with 
valgrind that is accurate for even single iterations as it's based on 
ticks. So please help me there, if you can.

Yours,
Kay Hayen