Re: Structure of the multitasking server

[Jean-Pierre Rosen <rosen@adalog.fr>]

Maciej Sobczak a �crit :
> Hi all,
> 
> Imagine a server with fixed number of worker tasks. There is no queue
> of jobs and jobs are immediately passed to one of the tasks that is
> currently idle. There is a separate task (or just the main one) that
> provides jobs for worker tasks.
[...]

Why not simply use a rendezvous?
Each worker has an entry Get_Job:

     task body Worker_Task is
        Job : Job_Type;
     begin
        loop
           Get_Job (Job);

           --  do the job ...

        end loop;
     end Worker_Task;

and the server is simply (assuming Servers is an array of Worker_Task):

     loop
        Job := ...

        Found_Worker := False;
        for I in Servers'Range loop
           select
              Server (I).Get_Job (Job);
              Found_Worker := True;
              exit;
           else
              -- This server is busy
              null;
           end select;
        end loop;

        if not Found_Worker then
           --  all pipelines are busy,
           --  but the overflow handling is not shown...
        end if;
     end loop;
-- 
---------------------------------------------------------
            J-P. Rosen (rosen@adalog.fr)
Visit Adalog's web site at http://www.adalog.fr