multiprocessor use w/ GPC compiled program (OT?)

[Russell Whitaker]

On Mon, 29 Mar 2004, Boris Herman wrote:
[..]
> My program doesn't really do anything much - it performs gazillions of
> computations in arrays that all together consume less than 20 Mb of
> memory.
>
20 Mb is several times the size of your L2 cache. The cpu uses only the
cache with a portion of the program plus some of the data in the cache,
so if the data the program needs isn't in the chunk of data in the cache
the cpu does a store & load cache operation.

For example, this simple program took 1.8 sec to run:

program huge;
var
  i,j : integer;
  BA : array [ 1..10000, 1..10000 ] of integer;
begin
  for i := 1 to 10000 do
    for j := 1 to 10000 do
      BA [ i,j ] := i+j;
end.

Change one line to read: BA [ j,i ] := i+j; and the program now takes
27 sec to run

Hope this helps,
  Russ