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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: Timing code blocks
Date: Fri, 05 Mar 2010 20:17:27 +0000
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I found the same results as Niklas, the compiler I'm running
is gcc version 4.5.0 20100221 (experimental) [trunk revision 156937]
(GCC) for x86_64-apple-darwin10.2.0.

I just added

   Junk_In    : Natural := 0;
   pragma Volatile (Junk_In);       -- <=====

after which -O[0123] all gave pretty similar results.

I didn't have to add 'delay 0.0;' to get the timings.

I did set

   Test_Dur : constant := 10_000;

and the timings on this Macbook Pro (2.4 GHz Core 2 Duo are of order
0.292 with -gnato, 0.254 without. The second loop is quicker with -O0.