Messages in this thread | | | Date | Fri, 24 Jan 2003 15:29:40 -0800 (PST) | From | "Randy.Dunlap" <> | Subject | Re: debate on 700 threads vs asynchronous code |
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On Sat, 25 Jan 2003, Matti Aarnio wrote:
| On Fri, Jan 24, 2003 at 04:53:46PM -0600, Corey Minyard wrote: | ... | > I would disagree. One thread per connection is easier to conceptually | > understand. In my experience, an event-driven model (which is what you | > end up with if you use one or a few threads) is actually easier to | > correctly implement and it tends to make your code more modular and | > portable. | | An old thing from early annals of computer science (I browsed Knuth's | "The Art" again..) is called Coroutine. | | Gives you "one thread per connection" programming model, but without | actual multiple scheduling threads in the kernel side. | | Simplest coroutine implementations are truly simple.. Pagefull of C. | Knuth shows it with very few MIX (assembly) instructions. | | Throwing in non-blocking socket/filedescriptor access, and in event | of "EAGAIN", coroutine-yielding to some other coroutine, does complicate | things, naturally. | | Good coder finds balance in between various methods, possibly uses | both coroutine "userspace threads", and actual kernel threads. | | Doing coroutine library all in portable C (by means of setjmp()/longjmp()) | is possible, but not very efficient. A bit of assembly helps a lot. | | > -Corey | | /Matti Aarnio | -
Davide Libenzi (epoll) likes and discusses coroutines on one of his web pages: http://www.xmailserver.org/linux-patches/nio-improve.html (search for /coroutine/)
-- ~Randy
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