Re: Developing multi-threading applications

From: Roberto Fichera (
Date: Thu Jun 13 2002 - 06:21:54 EST

At 03.13 13/06/02 -0700, you wrote:

>On Thu, 13 Jun 2002 11:08:27 +0200, Roberto Fichera wrote:
> >You are right! But "computational intensive" is not totaly right as I say ;-
> >),
> It's really not fair to change the premises in the middle of an
> argument.

Sorry ;-)!

> >because most of thread are waiting for I/O,
> Still wrong. You don't tie up threads waiting for I/O. You can
> wait without
>having a thread doing the waiting.
> >after I/O are performed the
> >computational intensive tasks, finished its work all the result are sent
> >to thread-father,
> Okay, so you need a new abstraction -- separate the waiting from the
>working. Create as many threads to do the work as you have processors to do
>the work on. As for the waiting, minimize threads waiting, they're pure
>overhead. If it's sockets, use 'poll' so one thread can do lots of waiting.

This's a possible solution.

> >the father collect all the child's result and perform some
> >computational work and send its result to its father and so on with many
> >thread-father controlling other child. So I think the main problem/overhead
> >is thread creation and the thread's numbers.
> So get rid of the problem! Don't create so many threads, create
> only as many
>threads as can do useful work and reuse them rather than destroying and
>recreating them. Solve the actual problem/overhead since it's totally
>artificial and due to your model rather than your problem!

Depending by the applications. With my simulation/emulation program I need
to create
many thread because each thread resolve/manage/compute a specific problem and
it's live depend by some factors. Each thread is create only if needed to
avoid the
overhead. The simulation/emulation is a "merge" of many and many object,
each object
work to resolve/manage/compute a specific problem. All the low objects are
grouped to
resolve a specific problem and are managed by a thread controller that
should take some
decision or doing some work. Some thread controller are grouped and managed
by another
thread controller and so on. Do not think that I need always 400 threads
active they are
create only if need by the controller. You must thinks this
simulation/emulation as collection
of many and many object that should interoperate, and the model is designed
to scale easily
on a distribuite environment.

> DS

Roberto Fichera.

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