Neil Schemenauer <nas-pyt...@arctrix.com> added the comment:
As I suspected, the performance impact is significant (although pretty small). Based on Linux perf, it looks like the extra test+branch in _Py_Dealloc adds about 1% overhead. pyperformance shows something similar, see attached reports (pypref-trashcan.txt and perf-annotate-trash.txt). An idea I've been trying is to add another type slot, e.g. tp_call_dealloc. It could be set by PyType_Ready(). It would be called by the Py_DECREF macro on refcnt going to zero. If the object is non-GC and Py_TRACE_REFS is off, can make tp_call_dealloc actually be the tp_dealloc pointer. If the type has the GC flag, point tp_call_dealloc to a _Py_Dealloc version that checks tp_is_gc and does the trashcan stuff. Unfortunately, all types don't have PyType_Ready() called on them. So, we cannot rely on tp_call_dealloc being set correctly. ---------- Added file: https://bugs.python.org/file50219/pyperf-trashcan.txt _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue44897> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
