New submission from STINNER Victor: Attached patch adds the following new function:
PyObject* _PyObject_CallStack(PyObject *func, PyObject **stack, int na, int nk); where na is the number of positional arguments and nk is the number of (key, pair) arguments stored in the stack. Example of C code to call a function with one positional argument: PyObject *stack[1]; stack[0] = arg; return _PyObject_CallStack(func, stack, 1, 0); Simple, isn't it? The difference with PyObject_Call() is that its API avoids the creation of a tuple and a dictionary to pass parameters to functions when possible. Currently, the temporary tuple and dict can be avoided to call Python functions (nice, isn't it?) and C function declared with METH_O (not the most common API, but many functions are declared like that). The patch only modifies property_descr_set() to test the feature, but I'm sure that *a lot* of C code can be modified to use this new function to beneift from its optimization. Should we make this new _PyObject_CallStack() function official: call it PyObject_CallStack() (without the understand prefix) or experiment it in CPython 3.6 and decide later to make it public? If it's made private, it will require a large replacement patch later to replace all calls to _PyObject_CallStack() with PyObject_CallStack() (strip the underscore prefix). The next step is to add a new METH_STACK flag to pass parameters to C functions using a similar API (PyObject **stack, int na, int nk) and modify the argument clinic to use this new API. Thanks to Larry Hasting who gave me the idea in a previous edition of Pycon US ;-) This issue was created after the discussion on issue #26811 which is an issue in a micro-optimization in property_descr_set() to avoid the creation of a tuple: it caches a private tuple inside property_descr_set(). ---------- files: call_stack.patch keywords: patch messages: 263899 nosy: haypo, larry, rhettinger, serhiy.storchaka priority: normal severity: normal status: open title: Add a new _PyObject_CallStack() function which avoids the creation of a tuple or dict for arguments type: performance versions: Python 3.6 Added file: http://bugs.python.org/file42549/call_stack.patch _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue26814> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com