Hi Andrew, On Thu, Apr 19, 2012 at 19:43, Andrew Francis <andrewfr_...@yahoo.com> wrote: > I am trying to understand enough to get into a position to attempt an > integration.
I believe you are trying to approach the problem from the bottom-most level up --- which is a fine way to approach problems; but in this case, you are missing that there are still a few levels between were you got so far and the destination, which is the stackless.py module in pure Python. Let us try to approach it top-down instead, because there are far less levels to dig through. The plan is to make any existing stackless-using program work on multiple cores. Take a random existing stackless example, and start to work by editing the pure Python lib_pypy/stackless.py (or, at first, writing a new version from scratch, copying parts of the original). The idea is to use the "transaction" module. The goal would be to not use the _squeue, which is a deque of pending tasklets, but instead to add pending tasklets with transaction.add(callback). Note how the notion of tasklets in the _squeue (which offers some specific order) is replaced by the notion of which callbacks have been added. See below for what is in each callback. The transaction.run() would occur in the main program, directly called by stackless.schedule(). So the callbacks are all invoked in the main program too; in fact all the "transaction" dispatching is done in the main program, and only scheduling new tasklets can occur anywhere. The callbacks would just contain a switch to the tasklet. When the tasklet comes back, if it is not finished, re-add() it. This is all. You have to make sure that all tasklet.switch()es internally go back to the main program, and not directly to another tasklet. This should ensure that the duration of every transaction is exactly the time in a tasklet between two calls to switch(). Of course, this can all be written and tested against "transaction.py", the pure Python emulator. Once it is nicely working, you are done. You just have to wait for a continuation-capable version of pypy-stm; running the same program on it, you'll get multi-core usage. A bientôt, Armin. _______________________________________________ pypy-dev mailing list pypy-dev@python.org http://mail.python.org/mailman/listinfo/pypy-dev
