[SciPy-dev] Valgrind primer
oliphant at ee.byu.edu
Fri Nov 4 18:27:52 CST 2005
I've been playing with valgrind to detect memory leaks and other memory
errors in scipy. It's a pretty nice tool. It often comes with most
Linux distributions (on my system urpmi valgrind installed it for me).
To use it to debug extension modules, you should have a Python compiled
with debugging symbols (-g) option. This will add debugging symbols to
extension modules as well. There is a file Misc/valgrind-python.supp
in the standard Python distribution that is needed to suppress some
useless Python memory warnings.
Then you can generate some useful output to the file testmem.pid<num>
using something like
valgrind --tool=memcheck --leak-check=yes --error-limit=no -v
--show-reachable=yes --num-callers=7 python leaktest.py
where leaktest.py is a file that exercises your code: i.e
Currently, my version of valgrind is issuing an illegal instruction in
eigenvalue computation when I run scipy.test(10,10) under valgrind.
That's probably O.K. because it would take a long time to finish anyway.
Everything runs a lot slower under valgrind, but you get some useful
information when it's done.
Feel free to post questionable items from your valgrind-generated log
files to this list (be sure they involve the PyArray_<something> or
PyUFunc_<something> C-API though. You may get errors from the Python
C-API too, but we can't fix those if needed here.).
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