Re: Robert Dewar's great article about the Strengths of Ada over other langauges in multiprocessing!

[Pascal Obry <pascal@obry.net>]

Maciej,

> I've seen 80x (eighty times) penalty when comparing Ada's protected
> objects with basic usage of mutexes in C++.
> 80x is not something to be taken lightly.

I've never seen such penalty. Maybe in theory or in a very specific part 
of the code. But let's compare the *final* application speed. I have 
gone this path in a medium simulation, the Ada implementation was slower 
in some part, the C++/OpenMP implementation was slower on some other 
part. The final application was running at same speed in Ada and C++ 
(well in fact the Ada implementation was a bit less than 1% faster than 
the C++ one).

Also, one point about the C++/MPI version (we also worked on a 
distributed version even if I don't have the final data, but speed was 
almost comparable) compared to the Ada Annex-E version. My co-worker 
were amazed at how fast I was able to re-configure the distributed 
application. Where it took days/weeks to change the MPI implementation, 
it took me hours to change the GLADE configuration file. Also, the 
facility to exchange Ada Containers objects across partitions was pretty 
amazing. No tweak, no hack, clean code, just plain Ada.

I know a group of C++ hackers still trying to come up with a clean 
solution to exchange objects (class instance) across nodes... Impossible 
to stream properly objects in C++, or you have to code almost all by 
hand! All these aspects are far more important to me than pure speed. I 
understand that this tradeoff can be different on some other 
applications, but I won't buy that this is majority of cases!

Pascal.

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