Bas Zoetekouw <[EMAIL PROTECTED]> 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 (http://shimizu-lab.dt.u-tokai.ac.jp/lsp.html).) 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 one? -- Falk
