Reply To: Parallel simulations slowing down significantly

[Maarten Vanierschot]

Thank you very much for your fast response! We have observed this behavior on hardware that should be supported (Intel IceLake 8360Y CPUs; a RHEL8-derived OS; with both ANSYS Fluent versions 2021R2 and 2022R2). Please also note that:

- it is a simple URANS simulation with only fluid flow and no special features
- these simulations employ dual-time stepping,
- the gradual slowdown also occurs when running on a single core (just a single MPI process),
- by printing timestamps at every step and iteration, we see that it is the individual iterations that are gradually taking more and more time,
- partial filling of RAM with file buffer caches can be excluded as a possible cause (the problem persists after flushing the cache).