[REBOL] Re: Multithreading with Rebol
From: andreas:bolka:gmx at: 17-Oct-2003 14:40
Friday, October 17, 2003, 2:11:47 PM, Robert wrote:
> On Tue, 14 Oct 2003 19:18:36 -0400, Brian Parkinson
> <[parki--whatevernot--com]> wrote:
>> I want to set up (say) a Rugby server, which will accept client
>> connections and process them. I'd like each connection to be handled in
>> its own thread (let's keep it simple and leave thread pools, resource
>> utilization and the like out of this) as I need each client's response
>> to be in reasonable time (pretend the processing involves I/O or
>> something). I'm kinda astonished that I can't do this in Rebol proper.
>> Unless I'm missing something real obvious, the only way that I can do
>> this is to rely on code that implements a cooperative multitasking
>> queue (a la Rugby) or roll my own (!).
> Hi, don't bee fooled by all this multi-threading hype. For example,
> have a look at www.xitami.com and theire LRWP protocol. This is done
> using a cooperative multi-tasking. Very cool and fast, and it can be
> coupled with Rebol quite easy.
The problem I see w/ coop multi-tasking (and I've implemented two coop
mt server frameworks in REBOL) is that it's a viral, an all-or-nothing
approach. If I have e.g. disk IO, I've to impl a simple file IO in a
coop way, i.e. decompositing it into a state machine w/ small tasks
that preferrably don't block. If I've some computing intensive
algorithm, once more, I've to state it in a coop way. And I (my very
personal opinion based on my experiences with that kind of stuff in
REBOL) find that decomposition rather boring and the result quite hard
to maintain. Imho, first class continuations would help in this
situation, but that's another topic.
So, when you control the whole application, it's at least possible to
completely adhere to a coop oriented programming approach. Once I want
to cleanly integrate with external apps or other libraries, yeah,
problems may arise - who guarantees that the library of my choice does
not use blocking IO, for example?
I'm in no way an expert in the theoretical issues surrounding this
topic, nor am I a REBOL guru. So it may well be that I've missed some
nifty ways to write something that won't require complete changes in
all my coding habits. So - questions, corrections and suggestions are
welcome :)
--
Best regards,
Andreas
