Parallel Efficiency Benchmarks about amgcl_benchmarks

[ddemidov]

AMGCL, as most iterative methods, is memory-bound. That is, its performance is limited by the available memory bandwidth. I believe the main difference between our results is hardware. The results in amgcl documentation are reported for a dual socket system with two Intel Xeon E5-2640 v3 CPUs. Each of the CPUs has 4 memory channels:

So the theoretical speedup limit on the system is around 8x. Your CPU has 2 memory channels, which agrees with the 2x speedup factor you observed.

You could also confirm this by running the stream benchmark on your system, which specifically tests the available memory bandwidth.

[garyyan123]

Thanks for pointing this out; we will pursue this direction further.