From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,7767a311e01e1cd
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII
Path: 
 g2news2.google.com!news4.google.com!news2.volia.net!news.ecp.fr!news.in2p3.fr!in2p3.fr!proxad.net!193.252.118.146.MISMATCH!news.wanadoo.fr!news.wanadoo.fr!not-for-mail
Message-ID: <453A532F.2070709@obry.net>
Date: Sat, 21 Oct 2006 19:04:47 +0200
From: Pascal Obry <pascal@obry.net>
Organization: Home - http://www.obry.net
User-Agent: Thunderbird 1.5 (Windows/20051201)
MIME-Version: 1.0
Newsgroups: comp.lang.ada
To: Jeffrey Creem <jeff@thecreems.com>
Subject: Re: GNAT compiler switches and optimization
References: <1161341264.471057.252750@h48g2000cwc.googlegroups.com>
 <9Qb_g.111857$aJ.65708@attbi_s21> <434o04-7g7.ln1@newserver.thecreems.com>
 <4539ce34$1_2@news.bluewin.ch> <nrup04-5hj.ln1@newserver.thecreems.com>
In-Reply-To: <nrup04-5hj.ln1@newserver.thecreems.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
NNTP-Posting-Date: 21 Oct 2006 19:04:51 CEST
NNTP-Posting-Host: 82.120.16.202
X-Trace: 1161450291 news.orange.fr 25940 82.120.16.202:4639
X-Complaints-To: abuse@orange.fr
Xref: g2news2.google.com comp.lang.ada:7117
Date: 2006-10-21T19:04:51+02:00
List-Id: <comp.lang.ada>

Jeffrey Creem a �crit :

> I'd certainly be willing to run a few benchmarks but the important thing
> here is that rather innocent looking code is running 2-4x slower than it
>  "should".

The first thing is to be sure that we are running the same program.

Running your program with the following changes (as done in Fortran):

1. Using Sum tmp var for the computation

   for I in A'range (1) loop
      for J in A'range (2) loop
         Sum := 0.0;
         for R in A'range (2) loop
            Sum := Sum + A (I, R) * B (R, J);
         end loop;
         C (I, J) := Sum;
      end loop;
   end loop;

2. Using Long_Float instead of Float (I think Fortran float is a
Long_Float, to be checked).

I went from 7.8s to 4.8s (with 1) and to 4.2s (with 2).

Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|              http://www.obry.net
--| "The best way to travel is by means of imagination"
--|
--| gpg --keyserver wwwkeys.pgp.net --recv-key C1082595