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Re: revivesa status 2008/07/09

On Jul 24, 2008, at 9:37 AM, Jason Thorpe wrote:
The right model for that is to use a continuation. Threads by their nature have stacks and other resources that make them too heavyweight to be appropriate for this type of processing.

No argument here. However, in practice there's no decent scheme compiler to use for this, so people wind up doing it in C with threads or state threads. In my experience, the cases where you need threads and not continuations are rare, and a lot of extra work is needed when doing threads that's completely unnecessary. Nevertheless, people persist in programming in C because there are good compilers, and continuations are... hard... in C.

Anyway, the more I think about this the more it seems to me that the need being discussed is specialized, and therefore probably doesn't need to be addressed by the default libc. It still seems like the work Bill is doing is worthwhile in this case, if a consequence of it is that someone who needs this functionality on their OLPC can choose the SCHEDULER_ACTIVATIONS option in the kernel and build a libc that will do what they want.

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