Re: How are CPU Speed and Overall CPW Related?

["Alexei Pytel" <pytel@xxxxxxxxxx>]

1. There are very few purely interpretive languages today. They all
precompile the source to some internal form, which is really very close to
compile. Which is especially true in your test, where you have very short
loop. Do you really think that FoxPro interprets every statement in your
loop as it is encountered ?

2. I want to attract once again your attention to the fact that you trim
*constant string* every time. Smart compiler will eliminate your entire
loop and replace it with a single statement. Change number of repetitions
from 500000 to 5000000. I will not be surprised if the timing will be
exactly the same.

3. I dare remind you that you constantly leave software out of the scope of
this discussion.
You want to compare PowerPC speed to Pentium speed. But what you do
actually compare is speed of RPG implementation in OS/400 environment on
PowerPC to speed of FoxPro implementation in Windows environment on
Pentium. Which is somewhat different thing, don't you think ?
Try some other programming languages on OS/400 for a better perspective.
Try C/C++ instead of RPG.
Several years ago when RISC was first out I took some standard LinPack
numerical benchmarks (they are all in C and with some massaging can be
easily ported to OS/400) and ran them on PC and OS/400. Results were quite
comparable.

So I personally suspect BIF implementation in RPG can be better. You may
ask RPG developers - maybe they will have some good answers - they could
have good reasons to implement it this way.

    Alexei Pytel



                                                                                
                   
                    "Nathan M. Andelin"                                         
                   
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> From: "Alexei Pytel" <pytel@us.ibm.com>

> I can't understand your obsession with "artificial constraints".
> It's much more complicated than that.

I'll try to address your comments in a future post, but while I have your
attention, I'll add a little more fuel to the fire.  Foxpro is an
interpreted language, and relatively slow.  So what about a compiled
language like Pascal?  Consider the following Delphi code:

procedure TForm1.Button1Click(Sender: TObject);
var
  theString : String;
  theShorter : String;
  i : integer;
  timeNow : TDateTime;
  timeThen : TDateTime;
  timeDiff : Real;

begin
  theShorter := 'TEST STRING                                        ';
  timeThen := Now;
  for i := 0 to 500000 do
  begin
   theString := TrimAll(theShorter);
  end;
  timeNow := Now;
  timeDiff := timeNow - timeThen;
  stringBox.text := theString;
  timeBox.text := FloatToStr(timeDiff);
end;


***
My older version of Delphi didn't have a TrimAll() function.  I had to
write
my own BIF:
***


function TrimAll(const S: string): string;
var
  I, L: Integer;
begin
  L := Length(S);
  I := 1;
  while (I <= L) and (S[I] < #33) do Inc(I);
  if I > L then Result := '' else
  begin
    while (S[L] < #33) do Dec(L);
    Result := Copy(S, I, L - I + 1);
  end;
end;

Like the RPG code, this program TRIMS all BLANKS off a 50 byte
string and assigns the result to another string variable.  The difference
is that the Intel based Pascal program runs 10 times faster.

What is constraining the AS/400 CPU?

Nathan.



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