STINNER Victor added the comment: 2013/10/6 Raymond Hettinger <rep...@bugs.python.org>: > I recommend that tracemalloc focus exclusively on real allocations and ignore > freelisting. The former are interesting because they directly affect > performance. Freelists on the other hand are close to being free (as in > beer).
The version of tracemalloc available on PyPI has patches to disable completly freelists or trace usage of freelists. It is important in Python 2 because some lists had no limit, especially int types. The version I wrote for Python 3.4 does not anything on freelists. Did you read the source code of the repository on python.org? > Measuring the freelist usage (or disabling it and then measuring) makes the > proposal more complex than necessary and doesn't provide useful information > (freelisting is no more interesting to track than saving a value in a static > variable). I would be nice to add metrics on freelists: number and size. Using tracemalloc, I'm trying to trace any byte. Such metrics can be optional (ex: a new method added to the Snapshot class). sys._debugmalloc() does already print all free lists. It should not be hard to write these information into structures, as I did for pymalloc statistics. Adding a method to read memory usage once is different than maintaining a structure (hash tables) to know that status anytime. > Another suggestion is to expand the API to provide a way to identify a > potential performance killer: the number of reallocs() than result in a new > pointer (because the data moved). I can add a global counter for each allocator (malloc, realloc, free) and each domain (raw, mem, obj). But I don't want to add a counter per trace, it would have a price on performances and memory footpring. > If you use hash table code from another project, be sure to check its > licensing. Done: see https://mail.python.org/pipermail/python-legal-sig/2013-September/000044.html ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue18874> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
