[fpc-devel] Vector Pascal (AKA Glasgow Pascal etc.)

[Mark Morgan Lloyd]

I see it gets discussed here once every three or four years, but I just 
thought I'd throw in that I've been playing briefly with the Vector (AKA 
Glasgow) compiler and get a quite impressive speedup when telling it to 
compile for two cores rather than one:

0 1>markMLl at pye-dev-07:~$ time ./test  # Compiled for 1 core

real    0m18.753s
user    0m18.733s
sys     0m0.000s

0 1>markMLl at pye-dev-07:~$ time ./test  # Compiled for two cores

real    0m11.908s
user    0m20.425s
sys     0m2.036s

Test program, based on an example in their manual:


program Test;

var     i: integer;

   procedure sub2d;

   type  range= 0..127;

   var   x, y, z: array[range, range] of single { real } ;

   begin
     x := y - z
   end;


begin
   {  WriteLn('Hello, World!') }
   for i := 0 to 65535 do
     sub2d
end.


I know it's pretty crappy and doesn't initialise variables etc., but I 
was interested to see if it really did distribute work properly.

I note FPC's undocumented -Sv option from earlier discussion, but it 
appears not to like the 2D array so compilation fails at the subtraction.

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]