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

[Martin Krischik <krischik@users.sourceforge.net>]

Norbert Caspari wrote:

> 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".

That's not a (missing) language feature it's a GNAT bug. Or prephaps not a
bug as such. See down below.

> I tested this with gnat v3.15p under HPUX 11 on a multi-cpu server.

When the GNAT compiler is compiled a specific thread can be activated. The
default for GNAT is "--enable-thread=gnat". This tread model has the
advantage that it is compatible with all gcc target operating systems. But
it won't have all the features available.

If you where a paying AdaCore customer you could just file an error report
at AdaCore and you would probably get a new compiler with a better thread
model activated pretty soon.

But since you use 3.15p I guess you are not a paying customer and here come
the bitter news: You have to to it yourself. That is: you need to get the
gcc sources (i.e from http://gnuada.sf.net) and compile your own compiler.
For unix systems I would suggest "--enable-theads=posix".

If you are successful: how about uploading the finshed compiler to The GNU
Ada Project?

Martin
-- 
mailto://krischik@users.sourceforge.net
Ada programming at: http://ada.krischik.com