Re: Ada tasking question

[Stefan Bellon <sbellon@sbellon.de>]

Jeffrey R. Carter wrote:

> Randy Brukardt wrote:
> > 
> > I'd suggest organizing the tasks as workers and the buckets as
> > jobs. The idea is that each task is a loop that just gets a job (a
> > bucket in your case), processes it, sends the result, and gets
> > another job, etc. You just need a protected data structure to serve
> > the jobs, and an array of worker tasks, and then you can easy vary
> > N to any value you want to try.

Thanks for this excellent idea! I have implemented that now.

> In this case, I'd say all that's needed is a protected object to
> supply the index into the Buckets array of the next bucket needing
> processing.

Yes, in fact I already implemented it this way before I saw your
posting. :-)

   protected Bucket_Jobs is
      procedure Init (Index : in Integer);
      entry Next (Index : out Integer);
   private
      Current : Integer;
   end Bucket_Jobs;

   protected body Bucket_Jobs is
      procedure Init (Index : in Integer) is
      begin
         Current := Index;
      end Init;

      entry Next (Index : out Integer) when True is
      begin
         Index := Current;
         Current := Current + 1;
      end Next;
   end Bucket_Jobs;

Initialization is done with Bucket_Jobs.Init (Buckets'First) and the
tasks themselves check for Current in Buckets'Range.

It kind of works, but I experience some other strange effect (see my
reply to Leif Holmgren).

-- 
Stefan Bellon