I have no idea what’s causing the “Undocumented” keys but let’s put that aside for now.
I ran your case on a Linux system with MFiX 25.1, using the serial solver and the SMP solver with 16 threads. I can reproduce your results:
Serial:
SMP
I also note that despite using 16 threads there is only a very slight speedup:
Serial:
SMP:
In serial mode, we reach t=10s in about 600 sec, in SMP we reach t=10 in 550 seconds. Not much of a speedup.
perf top shows that we are spending most of our time waiting, in the SMP case:
We need to look into the reasons for the different behavior, but in the meanwhile I’d advise that you simply not use SMP, as there seems to be little advantage in doing so.
I ran the case with a DMP configuration of 4x1x1 and got a slightly better speedup (and no anomalies):
This is about a 2X speedup over the serial case. If you have access to a Linux host you could try running with DMP. I’m not sure how well it will work on a Linux VM on a Windows host, but you could try it.