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From: "Martin Dowie" <martin.dowie@nospam.baesystems.com>
Newsgroups: comp.lang.ada
References: <e7ebd224.0202210437.1c7d0fbf@posting.google.com>
Subject: Re: How to speed up stream & record handling?
Date: Thu, 21 Feb 2002 14:17:00 -0000
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"Karl Ran" <karlran1234@yahoo.com> wrote in message
news:e7ebd224.0202210437.1c7d0fbf@posting.google.com...
> I've a problem getting a reasonable IO preformance from an Ada
> program (source is attached)
>
> The environment looks like this:
> OS: linux-2.4.16
> CPU: Intel P3/700 MHz / BX chipset
> compiler: gnat-3.14p

Have you tried varying compiler optimisations? i.e. -O3 instead of -O0?

The swap routine looks a little extravagant. You already know that
B_And_C is 2 bytes. Try:

   type Byte_Array is array (Positive range 1 .. 2) of Unsigned_8;

   -- This procedure reverses the oder of the bytes in its argument.
   procedure Swap (
         The_Bytes : in out Byte_Array ) is
      Temp : Unsigned_8 := The_Bytes (1);
   begin
      The_Bytes (1) := The_Bytes (2);
      The_Bytes (2) := Temp;
   end Swap;

and see if that makes any difference.

You could also try inlining your swap routine.

Hope this helps!

Slainte!
Martin