Model speed not increasing with additional CPU cores

danski

New member
I recently upgraded from a Ryzen 2700x (8 cores) to a Ryzen 5950x (16 cores). I am not seeing anywhere near the performance increase I was expecting. In fact, the model runtime does not improve beyond 8 processes on the 5950x. Given how WRF is able to scale well beyond this I find this unusual. Does anybody have any suggetions on identifying bottlenecks or other issues?

  • WRF 4.4.1 (dm) compiled with gcc/gfortran
  • Ubuntu 22.04.1 LTS
  • 32gb 3200mhz ram
  • 1 TB ssd
  • SMT off.
 
Did you change the mpirun -np (value) when you increased your cores?

For example

mpirun -np 6 ./real.exe -> mpirun -np 14 ./real.exe
 
Yes I did. I wonder if this has anything to do with using Ryzen consumer hardware. Does anybody have experience using Ryzen processors?
 
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Yes I did. I wonder if this has anything to do with using Ryzen consumer hardware. Does anybody have experience using Ryzen processors?
Can you attached your namelist.input and name list.wps so I can look at it.
 
@danski, Unfortunately our group does not have any experience using that hardware, but it's possible someone else who has will see this post and have some insight.
 
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