2012/1/21 Stefan Behnel <stefan...@behnel.de>: > Vitja Makarov, 19.01.2012 08:49: >> 2012/1/19 Robert Bradshaw: >>> On Wed, Jan 18, 2012 at 12:30 PM, Vitja Makarov wrote: >>>> I tried to optimize module lookups (__pyx_m) by caching internal PyDict >>>> state. >>>> >>>> In this example bar() is 1.6 time faster (500us against 842us): >>>> >>>> C = 123 >>>> def foo(a): >>>> return C * adef bar(): >>>> for i in range(10000): foo(i) >>>> Here is proof of >>>> concept:https://github.com/vitek/cython/commit/1d134fe54a74e6fc6d39d09973db499680b2a8d9 >>>> >>>> So the question is: does it worth it? >>> >>> I think the right thing to do here is make all module-level globals >>> into "cdef public" attributes, i.e. C globals with getters and setters >>> for Python space. I'm not sure whether this would best be done by >>> creating a custom dict or module subclass, but it would probably be >>> cleaner and afford much more than a 1.6x speedup. >> >> Yes, nice idea. >> It's possible to subclass PyModuleObject and I didn't find any use of >> PyModule_CheckExact() in CPython's sources: >> >> import types >> import sys >> >> global_foo = 1234 >> >> class CustomModule(types.ModuleType): >> def __init__(self, name): >> types.ModuleType.__init__(self, name) >> sys.modules[name] = self >> >> @property >> def foo(self): >> return global_foo >> >> @foo.setter >> def foo(self, value): >> global global_foo >> global_foo = value >> >> CustomModule('foo') >> >> import foo >> print foo.foo > > The one thing I don't currently see is how to get the module subtype > instantiated in a safe and portable way. >
We can do the same as types module: ModuleType = type(sys) or type(__builtins__) since we already got it (__pyx_b) > The normal way to create the module in Python 2.x is a call to > Py_InitModule*(), which internally does a PyImport_AddModule(). We may get > away with creating and registering the module object before calling into > Py_InitModule*(), so that PyImport_AddModule() finds it there. At least, > the internal checks on modules seem to use PyModule_Check() and not > PyModule_CheckExact(), so someone seems to have already thought about this. > > In Python 3.x, the situation is different. There is no lookup involved and > the module is always newly instantiated. That may mean that we have to copy > the module creation code into Cython. But that doesn't look like a huge > drawback (except for compatibility to potential future changes), because we > already do most of the module initialisation ourselves anyway, especially > now that we have CyFunction. > > I start feeling a bit like Linus Torvalds when he broke his minix > installation and went: "ok, what else do I need to add to this terminal > emulator in order to make it an operating system?" > -- vitja. _______________________________________________ cython-devel mailing list cython-devel@python.org http://mail.python.org/mailman/listinfo/cython-devel
