CPU usage issue

[reinh-bader]

CPU usage issue

[tschoonj]

That's a pretty big matrix so I am not surprised it eats into your CPU usage.

FGSL is really just a thin wrapper around GSL, so any performance issues will be due to the underlying GSL methods that are being called. You can confirm this by rewriting your program into C and use GSL directly.

[OakleyYoung]

Thank you for the quick response! Sorry, I should have said that the CPU usage is over multiple CPUs. I have run the same program in c and it uses 100% of 1 CPU, but when I write the same code in Fortran with fgsl it starts using nearly 100% of multiple CPUs.

[tschoonj]

Oh I understand now.

You seem to be using a for loop in your Fortran code that calls fgsl_splinalg_itersolve_iterate . Given that the top-level for loop iterations look independent to me, perhaps the Fortran compiler parallellized them out? Did you use some aggressive optimisation option while compiling? Perhaps try with all optimisations turned off (-O0) and see if the multithreading persists.

Either way, I am not convinced that FGSL could be responsible for this.

[OakleyYoung]

Thank you! Unfortunately turning off the optimizations seems to not work either. I am going to do a bit of research and see if other FORTRAN flags could be anyway related to multi-threading. Again thanks so much for the help and quick responses. Hopefully, I will be able to get it working!

[reinh-bader]

I am closing this issue as not directly related to the FGSL implementation.

[reinh-bader]

Question on usage was answered.