July 17, 2023 at 11:32 pm
Guilin Sun
Ansys Employee

I guess that you have only one engine license. If so, since one engine license can allow up to 32 cores, it is reasonable that when the two simulation are at the same time, each needs twice the time as when running single file. Please refer to

https://optics.ansys.com/hc/en-us/articles/360052724713-List-of-licensed-features-by-product

and check your license.

 

Please also check if one simulation really needs 32 cores. Maybe 16 or even 8 is sufficient. Due to parallel computing's limit on scaling, not every simulation needs more cores than 4 or 8, since the data communications among different blocks (each core simulate one block of the original file) of the simulation will also need time. when such communication time is not negligible, the scaling will deviate from linear relationship. from there, the more processes are used, the slower the simulation compared to n*#cores. Therefore the simulation efficiency is declined. It might be better to simulate two files at the same time but each simulation just uses 16 cores. Please set the cores/processes properly at "Resources" after some testing.