Model performance on NCAR's new 'Derecho' Cray EX system is worse than previous 'Cheyenne' SGI system.
Expected Behavior
In theory, Derecho should be 20-30% faster than Cheyenne.
Current Behavior
Initial model testing shows WRF-Hydro on Derecho to be 15% slower on average than the same runs on Cheyenne
Possible Solution
Communications fabric on Cray appears to favor fewer, larger transfers. Change small point-to-point MPI calls in the model to use larger Collective calls.
Your Environment
Version of the code used: v5.3.0
Operating System and version: SUSE Linux Enterprise Server 15 SP4
Compiler and version: Cray Compiler Environment
Other relevant information: NCAR Derecho Supercomputer
Model performance on NCAR's new 'Derecho' Cray EX system is worse than previous 'Cheyenne' SGI system.
Expected Behavior
In theory, Derecho should be 20-30% faster than Cheyenne.
Current Behavior
Initial model testing shows WRF-Hydro on Derecho to be 15% slower on average than the same runs on Cheyenne
Possible Solution
Communications fabric on Cray appears to favor fewer, larger transfers. Change small point-to-point MPI calls in the model to use larger Collective calls.
Your Environment