[capi-sig] running C method, benchmarks

[Campbell Barton]

Discussing if its worth moving Py/C functions from METH_VARARGS to
METHO when they only recieve 1 argument on the PyGame mailing list.
Crossposting here since some of you might be interested in the results.

tested different ways to evaluate args to see how much speed
difference there was
* 10,000,000 tests, python 2.6 on 32bit arch linux
* included a pass and NOARGS metrhod to see the difference in overhead
of the loop and parsing an arg compared to running a method with no
args.

---- output
pass 1.85659885406
METH_NOARGS 3.24079704285
METH_O 3.66321516037
METH_VARARGS 6.09881997108
METH_KEYWORDS 6.037307024
METH_KEYWORDS (as keyword) 10.9263861179

------- Python Script, (used blender module for testing)

import time

from Blender.sys import test_METHO, test_METH_VARARGS,
test_METH_KEYWORDS, test_METH_NOARGS

RUN = 10000000

t = time.time()
for i in xrange(RUN):   pass
print 'pass', time.time()-t

t = time.time()
for i in xrange(RUN):   test_METH_NOARGS()
print 'METH_NOARGS', time.time()-t

t = time.time()
for i in xrange(RUN):   test_METHO(1)
print 'METH_O', time.time()-t

t = time.time()
for i in xrange(RUN):   test_METH_VARARGS(1)
print 'METH_VARARGS', time.time()-t

t = time.time()
for i in xrange(RUN):   test_METH_KEYWORDS(1)
print 'METH_KEYWORDS', time.time()-t

t = time.time()
for i in xrange(RUN):   test_METH_KEYWORDS(val=1)
print 'METH_KEYWORDS (as keyword)', time.time()-t

------------------- C functions

static PyObject *test_METHO( PyObject * self, PyObject * value )
{
       int val = (int)PyInt_AsLong(value);

       if( val==-1 && PyErr_Occurred() ) {
               PyErr_SetString(PyExc_AttributeError, "not an int");
               return NULL;
       }

       Py_RETURN_NONE;
}

static PyObject *test_METH_VARARGS( PyObject * self, PyObject * args )
{
       int val;

       if( !PyArg_ParseTuple( args, "i", &val ) )
               return NULL;

       Py_RETURN_NONE;
}

static PyObject *test_METH_KEYWORDS( PyObject * self, PyObject * args,
PyObject *kwd)
{
       int val;
       static char *kwlist[] = {"val", NULL};

       if( !PyArg_ParseTupleAndKeywords(args, kwd, "i", kwlist, &val) )
               return NULL;

       Py_RETURN_NONE;
}

static PyObject *test_METH_NOARGS( PyObject * self, PyObject * args )
{
       Py_RETURN_NONE;
}

struct PyMethodDef M_sys_methods[] = {
       {"test_METHO", test_METHO, METH_O, ""},
       {"test_METH_KEYWORDS", test_METH_KEYWORDS, METH_KEYWORDS, ""},
       {"test_METH_NOARGS", test_METH_NOARGS, METH_NOARGS, ""},
       {"test_METH_VARARGS", test_METH_VARARGS, METH_VARARGS, ""},
       {NULL, NULL, 0, NULL}
};

-- 
- Campbell