OpenMP benchmark

[neapel]

Measure speedup

[mariomulansky]

I suggest to use nonlinear oscillator lattices, I have some tuned codes for that already we can check against.

[neapel]

1725e45 has a trivial benchmark to check if there's any kind of speedup but the values vary wildly with gcc's OpenMP library, with Intel's it's more stable...

[mariomulansky]

Maybe 1024 lorenz systems is still not enough to benefit from parallelization? For a proper benchmark I suggest to look at the scaling with cores. For such a loranz example, which is completely uncoupled, it should scale almost perfectly with the number of cores (or memory bandwidth for that matter)

[neapel]

Benchmark results for GCC 4.7.3 and ICC 13.1.1 on i7-3770 with (short) n=4096, 1024steps; (long) n=4194304, 1step; using (split) openmp_algebra=openmp_nested_algebra<range_algebra> with openmp_state or (simple) openmp_range_algebra with vector. All cases with schedule(runtime) and OMP_SCHEDULE=static.

[neapel]

Times for split/simple not comparable because simple case doesn't store values between cycles of the loop see here; all with release build; speedup with debug builds tend to be much larger but the times longer.