[Python-Dev] microthreading vs. async io (original) (raw)

Joachim König-Baltes joachim.koenig-baltes at emesgarten.de
Mon Feb 26 15:22:59 CET 2007

Adam Olsen wrote:

That would depend on whether Joachim's wait() refers to the individual tasks' calls or the scheduler's call. I assumed it referred to the scheduler. In the basic form it would literally be select.select(), which has O(n) cost and often fairly large n. The wait(events, timeout) call of a task would only mention the events that the task is interested in. The wait() call yields that list to the scheduler.

The scheduler then analyzes the list of events that tasks are waiting for and compares it to it's last call to select/poll/kevent and continues tasks in a round robin fashion until all events have been scheduled to the waiting tasks. Only when the scheduler has no events to deliver (e.g. all tasks are waiting) a new select/poll/kevent OS call is made by the scheduler, with a computed timeout to the lowest timeout value of all the tasks, so that a timeout can be delivered at the right time.

Joachim

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