Re: question about tasks, multithreading and multi-cpu machines

[Simon Wright <simon@pushface.org>]

Norbert Caspari <nnc@gmx.li> writes:

> In Ada it is possible to declare multiple parallel running "tasks". But for 
> my opinion the keyword "task" is somewhat misleding because in fact, those 
> "tasks" are really threads.

If you used VxWorks you would find that the right word to use was
'task' throughout. Threads/tasks mean different things to different
folk using different languages, get used to it.

On several platforms GNAT uses POSIX threads to implement tasking,
don't know about HPUX.

> If I run such a program on a multi-cpu machine, the process itself will use 
> only one cpu, even though I create several "tasks".
>
> I tested this with gnat v3.15p under HPUX 11 on a multi-cpu server.
>
> How can I write my code to utilize all cpu's on such a machine? Is there a 
> different way in Ada to perform multi-tasking instead of multi-threading?

I have had an SMP Linux x86 box for years, runs tasks on both CPUs
with no trouble (though I haven't used 3.15p for a long time).