Hello,<br><br> I was searching for the best mcpu option for amcc440, compiling and running a small program you can find here: <br>http://magnux.free.fr/gcc/mandelbrot.c. My distro is a ppc fedora core 6, and results are obviously the same using DENX4.0.<br><br>--------------------<br>-bash-3.00# gcc -O2 ./mandelbrot.c -o ./mandelbrot && time ./mandelbrot && rm -f ./mandelbrot<br><br>real 1m15.059s<br>user 1m14.996s<br>sys 0m0.060s<br>-bash-3.00# gcc -O2 -mcpu=440 ./mandelbrot.c -o ./mandelbrot && time ./mandelbrot && rm -f ./mandelbrot<br><br>real 0m39.606s<br>user 0m39.552s<br>sys 0m0.028s<br>-bash-3.00# gcc -O2 -mcpu=440fp ./mandelbrot.c -o ./mandelbrot && time ./mandelbrot && rm -f ./mandelbrot<br><br>real 1m15.016s<br>user
1m14.988s<br>sys 0m0.024s<br>-bash-3.00# gcc -O2 -msoft-float ./mandelbrot.c -o ./mandelbrot && time ./mandelbrot && rm -f ./mandelbrot<br><br>real 0m39.577s<br>user 0m39.544s<br>sys 0m0.032s<br>--------------------<br><br>* I do not explain why not using FPU gives better results ?<br><br>* I did also a test with bzip2.c ( http://pag.csail.mit.edu/~smcc/projects/single-file-programs/bzip2.c ).<br><br>----------------------<br>-bash-3.00# gcc -O2 ./bzip2.c -o ./bzip2 && time ./bzip2 ./oggenc.c && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2<br><br>real 0m18.478s<br>user 0m18.216s<br>sys 0m0.152s<br>-bash-3.00# gcc -O2 -mcpu=440 ./bzip2.c -o ./bzip2 && time ./bzip2 ./oggenc.c && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2<br><br>real
0m18.786s<br>user 0m18.544s<br>sys 0m0.128s<br>-bash-3.00# gcc -O2 -mcpu=440fp ./bzip2.c -o ./bzip2 && time ./bzip2 ./oggenc.c && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2<br><br>real 0m18.811s<br>user 0m18.548s<br>sys 0m0.144s<br>-bash-3.00# gcc -O2 -mcpu=G3 ./bzip2.c -o ./bzip2 && time ./bzip2 ./oggenc.c && ./bzip2 -d ./oggenc.c.bz2 && rm ./bzip2<br><br>real 0m18.871s<br>user 0m18.644s<br>sys 0m0.104s<br>----------------------<br><br>* mcpu option seems to not have any effect ?<br><br>* My third test was to compile and run mplayer.<br>- With default options (no mcpu specified), my test mpeg was smooth.<br>- With mcpu=440fp, my test mpeg was not smooth.<br><br> Can anybody bring me some lights about the right gcc mcpu option for amcc440 ?<br><br>Best
regards,<br><br> Patrice Bouchand<br><br><p> 
<hr size="1">
Découvrez une nouvelle façon d'obtenir des réponses à toutes vos questions !
Profitez des connaissances, des opinions et des expériences des internautes sur <a href="http://fr.rd.yahoo.com/evt=42054/*http://fr.answers.yahoo.com">Yahoo! Questions/Réponses</a>.