[New-bugs-announce] [issue22676] _pickle.c

[kbengine]

New submission from kbengine:

I have an application, the use of Python3.2.3 development.
When I upgrade to Python3.4.2, found a problem.

I have an extended "xxx.c (c-python)" module, I call pickle to serialize and deserialize, _pickle.c calls the whichmodule to look for this module, The final will be to find the module from sys.modules.

But probably there are 200 elements in sys.modules, Use the "obj = getattribute (module, global_name, allow_qualname)" to try to get the object:

static PyObject *
getattribute(PyObject *obj, PyObject *name, int allow_qualname) {
        ...
        ...
        ...

        tmp = PyObject_GetAttr(obj, subpath);
        Py_DECREF(obj);
 
// There will be hundreds of times to return to NULL
// There will be hundreds of times calls "PyErr_Format           
// (PyExc_AttributeError," Can't get attribute%R on%R ", name, obj);"
// This process will lead to hundreds of calls to "moduleobject.c-
// module_repr(PyModuleObject *m)".

// So I frequently call pickle.dumps CPU consumption sharply.

        if (tmp == NULL) {
            if (PyErr_ExceptionMatches(PyExc_AttributeError)) {
                PyErr_Clear();


                PyErr_Format(PyExc_AttributeError,
                             "Can't get attribute %R on %R", name, obj);
            }
            Py_DECREF(dotted_path);
            return NULL;
        }
       ...
       ...
}

------------------------------------------------------
   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
      315    0.001    0.000    0.004    0.000 <frozen importlib._bootstrap>:690(_module_repr)




I went wrong?
Look forward to answer, thanks!

----------
components: Extension Modules
files: 20141020193031.jpg
messages: 229723
nosy: kbengine
priority: normal
severity: normal
status: open
title: _pickle.c
type: performance
versions: Python 3.4
Added file: http://bugs.python.org/file36980/20141020193031.jpg

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue22676>
_______________________________________