[Bug-gnubg] compiling with optimization

[Achim Mueller]

Hi folks,

I just did a small test with different optimization flags.

machine:toshiba satellite 2430-101, 512mb RAM, 2,5 ghz pentium4
os:     SuSE-Linux 9.0, glibc-2.3.2-88, gcc-3.3.1

#: cat /proc/cpuinfo

cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Intel(R) Pentium(R) 4 CPU 2.53GHz
stepping        : 7
cpu MHz         : 2522.959
cache size      : 512 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge
                  mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2
                  ss ht tm
bogomips        : 4980.73


./configure:    --without-guile --without-gdbm --with-python
                --without-sound --without-board3d

without opt:    CFLAGS=""
i686:           CFLAGS="-march=i686 -mcpu=i686"
i686-O2:        same + O2
i686-O3:        same + O3
pentium4:       CFLAGS="-march=pentium4 -mcpu=pentium4"
pentium4-O2:    same + O2
pentium4-O3:    same + O3
pentium4-all:   same + -pipe -fomit-frame-pointer -fforce-addr
                       -falign-functions=4 -ffast-math


Results (gnubg -t "calibrate"):

without opt:    10954   12642
i686:           10985   11272
i686-O2:        22119   22125
i686-O3:        22386   22438
pentium4:       10996   11186
pentium4-O2:    23307   23255
pentium4-O3:    22849   22783
pentium4-all:   22815   22852


Interesting: If you don't use "-O" you get only half of the maximum.

Another point: While experimenting with the flag
"-fprefetch-loop-arrays" I get also only round about 12000.

Comments?

Ciao

Achim


-- 
achim mueller, anne-frank-str. 25, D-48431 rheine
+49 (0)5971 83767, +49 (0)163 8458340
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