[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: (re)compiling debian packages with ccc

Bas Zoetekouw <bas@debian.org> writes:

> I'm not sure if the gap has become smaller, but ccc still generated code
> that is a lot faster than gcc-3.2.
> For example, take a look at these results from SCIbench
> (http://math.nist.gov/scimark2), generated on an quadruple-proc EV67
> machine (running Tru64 Unix btw, not Linux):
> Compaq C compiler, V6.4-014 
> CFLAGS = -arch ev67 -fast -O4
> | Composite Score:          195.47
> GNU C compiler, V3.2.1
> CFLAGS = -O3 -fomit-frame-pointer -ffast-math -mcpu=ev67
> | Composite Score:          137.18

Well, you can beef up gcc's score a bit with -funroll-loops and
-fprefetch-array-loops (ccc does these optimizations without needing
to be kicked). On an 800MHz ev68 (with some background load) I get:

gcc version 3.2.2 20030131 (Debian prerelease)
CFLAGS = -O3 -fomit-frame-pointer -ffast-math -mcpu=ev67 -funroll-loops -fprefetch-loop-arrays 
| Composite Score:          149.17
| FFT             Mflops:   226.05    (N=1024)
| SOR             Mflops:   186.61    (100 x 100)
| MonteCarlo:     Mflops:    57.64
| Sparse matmult  Mflops:   106.21    (N=1000, nz=5000)
| LU              Mflops:   169.36    (M=100, N=100)

Compaq C V6.5-001
CFLAGS = -arch ev67 -fast -O4
| Composite Score:          170.43
| FFT             Mflops:   247.80    (N=1024)
| SOR             Mflops:   226.62    (100 x 100)
| MonteCarlo:     Mflops:    53.78
| Sparse matmult  Mflops:    92.64    (N=1000, nz=5000)
| LU              Mflops:   231.30    (M=100, N=100)

Well, still 14% better, but this is with a benchmark from an area
where ccc really excels. However, this benchmark is way from
representive for most stuff in Debian; it uses lots of floating point,
a tiny code working set, large data working sets, and simple data
access patterns. (BTW, I guess it could be sped up a lot with the
superpage kernel patch

It would really be nice if there was a useful free benchmark, like
specint, with real world code from diverse areas... does any body know


Reply to: