Author: Wim Lavrijsen <wlavrij...@lbl.gov> Branch: Changeset: r54600:e6931441abcb Date: 2012-04-20 15:28 -0700 http://bitbucket.org/pypy/pypy/changeset/e6931441abcb/
Log: cppyy doc: introduction of the fast path diff --git a/pypy/doc/cppyy.rst b/pypy/doc/cppyy.rst --- a/pypy/doc/cppyy.rst +++ b/pypy/doc/cppyy.rst @@ -37,7 +37,7 @@ easily provided by the packager of your system. If you read up on gccxml, you'll probably notice that it is no longer being developed and hence will not provide C++11 support. -That's why the medium plan is to move to `cling`_. +That's why the medium term plan is to move to `cling`_. .. _`Download`: http://root.cern.ch/drupal/content/downloading-root .. _`source`: http://root.cern.ch/drupal/content/installing-root-source @@ -241,6 +241,35 @@ You can always find more detailed examples and see the full of supported features by looking at the tests in pypy/module/cppyy/test. + +The fast lane +============= + +The following is an experimental feature of cppyy, and that makes it doubly +experimental, so caveat emptor. +With a slight modification of Reflex, it can provide function pointers for +C++ methods, and hence allow PyPy to call those pointers directly, rather than +calling C++ through a Reflex stub. +This results in a rather significant speed-up. +Mind you, the normal stub path is not exactly slow, so for now only use this +out of curiosity or if you really need it. + +To install this patch of Reflex, locate the file genreflex-methptrgetter.patch +in pypy/module/cppyy and apply it to the genreflex python scripts found in +``$ROOTSYS/lib``:: + + $ cd $ROOTSYS/lib + $ patch -p2 < genreflex-methptrgetter.patch + +With this patch, ``genreflex`` will have grown the ``--with-methptrgetter`` +option. +Use this option when running ``genreflex``, and add the +``-Wno-pmf-conversions`` option to ``g++`` when compiling. +The rest works the same way: the fast path will be used transparently (which +also means that you can't actually find out whether it is in use, other than +by running a micro-benchmark). + + CPython ======= _______________________________________________ pypy-commit mailing list pypy-commit@python.org http://mail.python.org/mailman/listinfo/pypy-commit
