Debug Python stacks revisited - experimental build in Rawhide, targetting Fedora 14

[David Malcolm]

On Mon, 2010-05-24 at 20:11 -0400, David Malcolm wrote:
> On Thu, 2010-05-20 at 15:37 -0400, David Malcolm wrote:

[snip]

> I'm working next on enabling more of the debug flags in the debug
> builds;  you can see status on the under-construction feature page here:
> https://fedoraproject.org/wiki/DaveMalcolm/DebugPythonStacks

I've now enabled WITH_TSC, with COUNT_ALLOCS, and CALL_PROFILE for both
python and python3 (see the wiki page above for the specific builds).

[david at surprise devel]$ python3-debug
Python 3.1.2 (r312:79147, May 25 2010, 12:21:20) 
[GCC 4.4.3 20100422 (Red Hat 4.4.3-18)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys ; from pprint import pprint
[32089 refs]
>>> pprint(sys.getcounts())
[('ImportError', 2, 2, 1),
 ('_Helper', 1, 0, 1),
 ('_Printer', 3, 0, 3),
[snip]
 ('dict', 3671, 3325, 389),
 ('str', 16194, 12860, 3334),
 ('tuple', 13995, 12300, 1740)]
[32101 refs]

One issue is that COUNT_ALLOCS seems to unconditionally log debug
information to stdout on exit:
memoryview alloc'd: 2, freed: 2, max in use: 1
ImportError alloc'd: 2, freed: 2, max in use: 1
_Helper alloc'd: 1, freed: 1, max in use: 1
_Printer alloc'd: 3, freed: 3, max in use: 3

which is likely to break scripts that capture stdout from python
scripts.

It seems useful to have sys.getcounts(), so perhaps we should talk with
upstream and instead emit counts to stderr instead, or make this only
happen if an envvar is set, or simply omit it.

Thoughts?
Dave