From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from web23402.mail.ird.yahoo.com (web23402.mail.ird.yahoo.com [217.146.189.87]) by ozlabs.org (Postfix) with SMTP id C115FDDD07 for ; Thu, 22 Feb 2007 17:58:01 +1100 (EST) Date: Thu, 22 Feb 2007 07:57:59 +0100 (CET) From: Patrice Bouchand Subject: RE : Re: mcpu options for AMCC440 with fpu To: linuxppc-embedded@ozlabs.org In-Reply-To: <20070221223543.64d584d7.mh@omnisys.se> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-334689501-1172127479=:61964" Message-ID: <447407.61964.qm@web23402.mail.ird.yahoo.com> List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --0-334689501-1172127479=:61964 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Thanks for your answer but unfortunately, it makes just the thing a bit slower: -bash-3.00# gcc -O2 -mcpu=440fp -ffast-math ./mandelbrot.c -o ./mandelbrot && time ./mandelbrot && rm -f ./mandelbrot real 1m17.901s user 1m17.828s sys 0m0.036s -bash-3.00# gcc -O2 -mcpu=440 -ffast-math ./mandelbrot.c -o ./mandelbrot && time ./mandelbrot && rm -f ./mandelbrot real 0m41.180s user 0m41.116s sys 0m0.040s -bash-3.00# gcc -O2 -mcpu=G3 -ffast-math ./mandelbrot.c -o ./mandelbrot && time ./mandelbrot && rm -f ./mandelbrot real 1m14.820s user 1m14.760s sys 0m0.044s Magnus Hjorth a écrit : Hi, Have you tried using the -ffast-math option? /Magnus On Wed, 21 Feb 2007 20:47:50 +0100 Patrice Bouchand wrote: > > FYI, I got the following answer on mplayer mailing list: > > > Apparently -mcpu=440fp is the one. However, it's possible, that GCC > > "optimizations" actually make the code slower. > > Can someone confirme this possiblity ? > > Any answer would be greatly appreciated ;) > > > Patrice Bouchand > > > > Hello, > > > > I was searching for the best mcpu option for amcc440, compiling and > > running a small program you can find here: > > http://magnux.free.fr/gcc/mandelbrot.c. My distro is a ppc fedora core > > 6, and results are obviously the same using DENX4.0. > > > > -------------------- > > -bash-3.00# gcc -O2 ./mandelbrot.c -o ./mandelbrot && > > time ./mandelbrot && rm -f ./mandelbrot > > > > real 1m15.059s > > user 1m14.996s > > sys 0m0.060s > > -bash-3.00# gcc -O2 -mcpu=440 ./mandelbrot.c -o ./mandelbrot && > > time ./mandelbrot && rm -f ./mandelbrot > > > > real 0m39.606s > > user 0m39.552s > > sys 0m0.028s > > -bash-3.00# gcc -O2 -mcpu=440fp ./mandelbrot.c -o ./mandelbrot && > > time ./mandelbrot && rm -f ./mandelbrot > > > > real 1m15.016s > > user 1m14.988s > > sys 0m0.024s > > -bash-3.00# gcc -O2 -msoft-float ./mandelbrot.c -o ./mandelbrot && > > time ./mandelbrot && rm -f ./mandelbrot > > > > real 0m39.577s > > user 0m39.544s > > sys 0m0.032s > > -------------------- > > > > * I do not explain why not using FPU gives better results ? > > > > * I did also a test with bzip2.c > > ( http://pag.csail.mit.edu/~smcc/projects/single-file-programs/bzip2.c ). > > > > ---------------------- > > -bash-3.00# gcc -O2 ./bzip2.c -o ./bzip2 && time ./bzip2 ./oggenc.c > > && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2 > > > > real 0m18.478s > > user 0m18.216s > > sys 0m0.152s > > -bash-3.00# gcc -O2 -mcpu=440 ./bzip2.c -o ./bzip2 && > > time ./bzip2 ./oggenc.c && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2 > > > > real 0m18.786s > > user 0m18.544s > > sys 0m0.128s > > -bash-3.00# gcc -O2 -mcpu=440fp ./bzip2.c -o ./bzip2 && > > time ./bzip2 ./oggenc.c && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2 > > > > real 0m18.811s > > user 0m18.548s > > sys 0m0.144s > > -bash-3.00# gcc -O2 -mcpu=G3 ./bzip2.c -o ./bzip2 && > > time ./bzip2 ./oggenc.c && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2 > > > > real 0m18.871s > > user 0m18.644s > > sys 0m0.104s > > ---------------------- > > > > * mcpu option seems to not have any effect ? > > > > * My third test was to compile and run mplayer. > > - With default options (no mcpu specified), my test mpeg was smooth. > > - With mcpu=440fp, my test mpeg was not smooth. > > > > Can anybody bring me some lights about the right gcc mcpu option for > > amcc440 ? > > > > Best regards, > > > > Patrice Bouchand > > > > > > > > > > ______________________________________________________________________ > > Découvrez une nouvelle façon d'obtenir des réponses à toutes vos > > questions ! Profitez des connaissances, des opinions et des > > expériences des internautes sur Yahoo! Questions/Réponses. > > _______________________________________________ > > Linuxppc-embedded mailing list > > Linuxppc-embedded@ozlabs.org > > https://ozlabs.org/mailman/listinfo/linuxppc-embedded > > _______________________________________________ > Linuxppc-embedded mailing list > Linuxppc-embedded@ozlabs.org > https://ozlabs.org/mailman/listinfo/linuxppc-embedded --------------------------------- Découvrez une nouvelle façon d'obtenir des réponses à toutes vos questions ! Profitez des connaissances, des opinions et des expériences des internautes sur Yahoo! Questions/Réponses. --0-334689501-1172127479=:61964 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit
Thanks for your answer but unfortunately, it makes just the thing a bit slower:

-bash-3.00# gcc -O2 -mcpu=440fp -ffast-math ./mandelbrot.c -o ./mandelbrot && time ./mandelbrot && rm -f ./mandelbrot

real    1m17.901s
user    1m17.828s
sys     0m0.036s
-bash-3.00# gcc -O2 -mcpu=440 -ffast-math ./mandelbrot.c -o ./mandelbrot && time ./mandelbrot && rm -f ./mandelbrot

real    0m41.180s
user    0m41.116s
sys     0m0.040s
-bash-3.00# gcc -O2 -mcpu=G3 -ffast-math ./mandelbrot.c -o ./mandelbrot && time ./mandelbrot && rm -f ./mandelbrot

real    1m14.820s
user    1m14.760s
sys     0m0.044s


Magnus Hjorth <mh@omnisys.se> a écrit :
Hi,

Have you tried using the -ffast-math option?

/Magnus


On Wed, 21 Feb 2007 20:47:50 +0100
Patrice Bouchand wrote:

>
> FYI, I got the following answer on mplayer mailing list:
>
> > Apparently -mcpu=440fp is the one. However, it's possible, that GCC
> > "optimizations" actually make the code slower.
>
> Can someone confirme this possiblity ?
>
> Any answer would be greatly appreciated ;)
>
>
> Patrice Bouchand
>
>
> > Hello,
> >
> > I was searching for the best mcpu option for amcc440, compiling and
> > running a small program you can find here:
> > http://magnux.free.fr/gcc/mandelbrot.c. My distro is a ppc fedora core
> > 6, and results are obviously the same using DENX4.0.
> >
> > --------------------
> > -bash-3.00# gcc -O2 ./mandelbrot.c -o ./mandelbrot &&
> > time ./mandelbrot && rm -f ./mandelbrot
> >
> > real 1m15.059s
> > user 1m14.996s
> > sys 0m0.060s
> > -bash-3.00# gcc -O2 -mcpu=440 ./mandelbrot.c -o ./mandelbrot &&
> > time ./mandelbrot && rm -f ./mandelbrot
> >
> > real 0m39.606s
> > user 0m39.552s
> > sys 0m0.028s
> > -bash-3.00# gcc -O2 -mcpu=440fp ./mandelbrot.c -o ./mandelbrot &&
> > time ./mandelbrot && rm -f ./mandelbrot
> >
> > real 1m15.016s
> > user 1m14.988s
> > sys 0m0.024s
> > -bash-3.00# gcc -O2 -msoft-float ./mandelbrot.c -o ./mandelbrot &&
> > time ./mandelbrot && rm -f ./mandelbrot
> >
> > real 0m39.577s
> > user 0m39.544s
> > sys 0m0.032s
> > --------------------
> >
> > * I do not explain why not using FPU gives better results ?
> >
> > * I did also a test with bzip2.c
> > ( http://pag.csail.mit.edu/~smcc/projects/single-file-programs/bzip2.c ).
> >
> > ----------------------
> > -bash-3.00# gcc -O2 ./bzip2.c -o ./bzip2 && time ./bzip2 ./oggenc.c
> > && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2
> >
> > real 0m18.478s
> > user 0m18.216s
> > sys 0m0.152s
> > -bash-3.00# gcc -O2 -mcpu=440 ./bzip2.c -o ./bzip2 &&
> > time ./bzip2 ./oggenc.c && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2
> >
> > real 0m18.786s
> > user 0m18.544s
> > sys 0m0.128s
> > -bash-3.00# gcc -O2 -mcpu=440fp ./bzip2.c -o ./bzip2 &&
> > time ./bzip2 ./oggenc.c && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2
> >
> > real 0m18.811s
> > user 0m18.548s
> > sys 0m0.144s
> > -bash-3.00# gcc -O2 -mcpu=G3 ./bzip2.c -o ./bzip2 &&
> > time ./bzip2 ./oggenc.c && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2
> >
> > real 0m18.871s
> > user 0m18.644s
> > sys 0m0.104s
> > ----------------------
> >
> > * mcpu option seems to not have any effect ?
> >
> > * My third test was to compile and run mplayer.
> > - With default options (no mcpu specified), my test mpeg was smooth.
> > - With mcpu=440fp, my test mpeg was not smooth.
> >
> > Can anybody bring me some lights about the right gcc mcpu option for
> > amcc440 ?
> >
> > Best regards,
> >
> > Patrice Bouchand
> >
> >
> >
> >
> > ______________________________________________________________________
> > Découvrez une nouvelle façon d'obtenir des réponses à toutes vos
> > questions ! Profitez des connaissances, des opinions et des
> > expériences des internautes sur Yahoo! Questions/Réponses.
> > _______________________________________________
> > Linuxppc-embedded mailing list
> > Linuxppc-embedded@ozlabs.org
> > https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded

Découvrez une nouvelle façon d'obtenir des réponses à toutes vos questions ! Profitez des connaissances, des opinions et des expériences des internautes sur Yahoo! Questions/Réponses. --0-334689501-1172127479=:61964--