[pypy-dev] Towards Milestone 1

[Jacob Hallén]

onsdagen den 10 augusti 2005 22.47 skrev Armin Rigo:

> * threading: implementing this requires a mixture of source-code-level
>   changes and help from the translation process, depending on the
>   approach taken.  At the moment we have no threads at all.  There are
>   two threading models that are relatively easy to implement by now, and
>   more to think about:
...
>   3) there are also other less well-thought ideas for threading, mostly
>      along the lines of per-object locking.  Here too, it should be
>      possible to get a not-too-bad result without having to insert locks
>      everywhere by hand.  For example, we could reuse the proxy object
>      space mechanism for a LockingObjSpace which first acquires the lock
>      of each object involved in each space operation.
>
> * finally, let's consider the translation process itself.  It is
>   flexible in principle, but it's not really designed as a framework
>   with a well-defined API or hooks to plug into.  However, it is
>   possible to hack here and there to change various translation aspects.
>   This is, to some extent, the whole idea of PyPy's flexibility: a
>   framework with hooks and APIs allows only so much experimentation;
>   sooner or later the ability to directly code things differently is
>   more powerful.  Nevertheless I guess that some refactoring would help
>   to make localized translation aspects easier to change, e.g. by providing
>   more "policy" objects to control the process, or (for OOP enthusiasts)
>   by designing the classes with subclassing in mind.

A loose idea that I have had would be to have one object space per thread. 
There would be several different possibilities for how to access an object 
that isn't in your own object space; one would be that the creating thread 
would continue to own the object. Another one would be to marshal the object 
and transfer it. A third one would be to transfer shared object to a shared 
object space.

Jacob