[coyotos-dev] Thoughts on FCRBs and asynchrony

[Jonathan S. Shapiro]

On Tue, 2006-02-07 at 15:20 -0700, Christopher Nelson wrote:

> My first question is, how do activations (or continuations) simplify a
> program versus threads, when you consider that an activation (or
> continuation) is basically just a special thread?  In other words, if
> you do anything that could interfere with the operation of the
> previously interrupted line of execution, you still have to worry about
> synchronization.

In some uses they do not simplify. It depends on your programming idiom.

One idiom where things DO simplify is the event-driven program. I can
have lots of outstanding FCRBs. When the corresponding events arrive, I
will enqueue them for later processing.

In this idiom, you will discover that there are exactly two user-mode
threads: the main worker thread and the thread that performs the
enqueueing of events. The enqueueing thread won't require floating point
state, etc.


shap