Messages in this thread | | | Date | Fri, 24 Jan 2003 16:11:35 -0800 | From | Dan Kegel <> | Subject | Re: debate on 700 threads vs asynchronous code |
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Randy.Dunlap wrote: > 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. ... > | 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.
There's also an elegant implementation that uses switch statements or computed gotos; see http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html I'm using it. It's a bit limited, but hey, it works for me.
> 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/)
IMHO coroutines are harder to use than either threads or nonblocking I/O. Then again, I don't like Scheme; many things in this world are a matter of taste. - Dan
-- Dan Kegel http://www.kegel.com http://counter.li.org/cgi-bin/runscript/display-person.cgi?user=78045
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