GCC Benchmarks (coybench), AMD64 and i686, 14 August 2004

[Scott Robert Ladd]

Kaveh R. Ghazi wrote:
>  > >icc -E -dM -O3 -xN qq.c | grep INLINE
>  > #define __NO_MATH_INLINES 1
>  > #define __NO_STRING_INLINES 1
>  > #define __NO_INLINE__ 1
> 
> 
> Well, I for one think this is *highly* unfair. :-)
> If icc gets to avoid using glibc's macros, then so should we!

This issue has arisen before. Let's throw all these suggestions together 
(including the suggested changes in "mole"), run some compiles with GCC 
3.5-20040814, and see what we get:

A = gcc -o bench_3.5_O3_p4 -lrt -lm -std=gnu99
         -O3
         -march=pentium4
         *.c

B = gcc -o bench_3.5_O3_p4_fm -lrt -lm -std=gnu99
         -O3
         -march=pentium4
         -ffast-math
         *.c

C = gcc -o bench_3.5_all -lrt -lm -std=gnu99
         -O3
         -march=pentium4
         -ffast-math
         -mfpmath=sse
         -D__NO_MATH_INLINES
         -D__NO_STRING_INLINES
         -D__NO_INLINE
         *.c

icc = icc -o iccbench -O3 -xN -tpp7 -ipo -lm -lrt *.c

               A      B      C     icc
             -----  -----  -----  -----
      alma:   43.2   22.2   23.7   13.2
      arco:   27.4   27.2   27.2   20.5
       evo:   43.4   42.0   63.8   29.8
       fft:   27.7   27.5   28.4   30.4
      huff:   13.9   13.1   13.2   16.4
       lin:   20.2   19.6   19.8   19.2
      mat1:    7.7    7.5    7.4    7.4
      mole:    8.8    6.7    6.8    2.1
      tree:   26.0   25.7   25.8   28.8
     -----   -----  -----  -----  -----
     total:  218.4  191.7  216.2  167.8

Hmmmm... I don't see where adding the -D__NO_??? options helped GCC -- 
in fact, those options hindered run time severely on the evo test!

Now people know why I don't specify all those #defines when I run my 
tests; I haven't seen a measurable gain in generated code speed from 
their use.

I note that ICC wins 4 benchmarks decisively, including three are are 
wholly of my own design and completely original (alma, arco, evo). 
Furthermore, the code changes in "mole" helped both gcc and icc.

I'm likely to toss out mat1 and mole soon, replacing them with a wavelet 
transform and a particle system computation.

More food for thought, I hope.

-- 
Scott Robert Ladd
Coyote Gulch Productions (http://www.coyotegulch.com)
Software Invention for High-Performance Computing