Aahz wrote:
On Sun, Mar 25, 2007, Talin wrote:
Thinking more about this, it seems to me that discussions of syntax for doing parallel operations and nifty classes for synchronization are a bit premature. The real question, it seems to me, is how to get Python to operate concurrently at all.
Maybe that's what it seems to you; to others of us who have been looking at this problem for a while, the real question is how to get a better multi-process control and IPC library in Python, preferably one that is cross-platform. You can investigate that right now, and you don't even need to discuss it with other people.
If you mean some sort of inter-process messaging system, there are a number that already exist; I'd look at IPython and py-globus for starters. My feeling is that while such an approach is vastly easier from the standpoint of Python developers, and may be easier from the standpoint of a typical Python programmer, it doesn't actually solve the problem that I'm attempting to address, which is figuring out how to write client-side software that dynamically scales to the number of processors on the system. My view is that while the number of algorithms that we have that can be efficiently parallelized in a fine-grained threading environment is small (compared to the total number of strictly sequential algorithms), the number of algorithms that can be adapted to heavy-weight, coarse-grained processes is much smaller still. For example, it is easy to imagine a quicksort routine where different threads are responsible for sorting various sub-partitions of the array. If this were to be done via processes, the overhead of marshalling and unmarshalling the array elements would completely swamp the benefits of making it concurrent. -- Talin