Re: Developing multi-threading applications

[Roberto Fichera <kernel@tekno-soft.it>]

At 11.31 13/06/02 +0200, Ingo Oeser wrote:

>On Thu, Jun 13, 2002 at 11:08:27AM +0200, Roberto Fichera wrote:
> > You are right! But "computational intensive" is not totaly right as I 
> say ;-),
> > because most of thread are waiting for I/O, after I/O are performed the
> > computational intensive tasks, finished its work all the result are sent
> > to thread-father, 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 you are creating a simulation/emulation application/engine, right?
>Or a measured data analysis engine? (which is basically the same
>task)

Yes! It's a simulation/emulation application.

>For these kind of tasks creating your own kind of "threads" is
>probably better.
>
>Split it in the following data structure:
>
>struct my_thread {
>    actor_function_t actor;
>    input_t inbuf;
>    output_t outbuf;
>    state_t statebuf;
>}
>
>And provide rules and primitives for accessing inbuf/outbuf, if
>they might be shared (which is probable).

This can be a solution.


>Now you can build a dependency tree/graph for the whole stuff
>easily and schedule works of the same level to some real worker
>threads (which might be on different machines), which are one per CPU.
>
>The problem is to build the actor as a REAL primitive, that
>scales only by the size of inbuf and not by the contents of it.

Yes!

>Everything else is going to be bloated and not really scalable,
>but can be implemented by every "Joe Programmer" after finishing
>high school ;-)

Depending by the threading library, if it's totaly userspace or not!
With so many thread that aren't totaly userspace the scheduler
performances/caratteristics are much important. I prefer a mixed
solution for example. Because some problem can be easily resolved
with a userspace threads and other not.


>Regards
>
>Ingo Oeser
>--
>Science is what we can tell a computer. Art is everything else. --- D.E.Knuth

Roberto Fichera.