[Python-Dev] microthreading vs. async io

[Joachim König-Baltes]

Adam Olsen schrieb:
> I don't think we're on the same page then.  The way I see it you want
> a single async IO implementation shared by everything while having a
> collection of event loops that cooperate "just enough".  The async IO
> itself would likely end up being done in C.
>
No, I'd like to have:

- An interface for a task to specifiy the events it's interested in, and 
waiting
  for at least one of the events (with a timeout).
- an interface for creating a task (similar to creating a thread)
- an interface for a schedular to manage the tasks

When a task resumes after a wait(...) it knows which of the events it was
waiting for have fired. It can then do whatever it wants, do the low 
level non
blocking IO on its own or using something else. Of course, as these are
cooperative tasks, they still must be careful not to block, e.g. not reading
to much from a file descriptor that is readable, but these problems have
been solved in a lot of libraries, and I would not urge the task to use a
specific way to accomplish its "task".

The problem solved by this approach is to allow a number of cooperating
threads to wait for an event without the need to busy loop or block by 
delegating
the waiting to a central instance, the scheduler. How this efficient 
waiting is
implemented is the responsability of the scheduler, but the schedular would
not do the (possibly blocking) io operation, it would only guaranty to
continue a task, when it can do an IO operation without blocking.

Joachim