MPI_Direct benefits ?

Describe the issue

I see no gain using MPI_Direct during solve except during setup.
Environment information:

• OS: Linux
• CUDA runtime: All
• MPI version (if applicable):All
• AMGX version: 2.5.0
• NVIDIA GPU: All

AMGX solver configuration

AmgX config file

config_version=2
solver(s)=PCG
s:convergence=RELATIVE_INI_CORE
s:tolerance=1.000000e-06
s:preconditioner(p)=AMG
s:use_scalar_norm=1
p:error_scaling=0
p:print_grid_stats=1
p:max_iters=1
p:cycle=V
p:min_coarse_rows=2
p:max_levels=100
p:smoother(smoother)=BLOCK_JACOBI
p:presweeps=1
p:postsweeps=1
p:coarsest_sweeps=1
p:coarse_solver=DENSE_LU_SOLVER
p:dense_lu_num_rows=2
p:algorithm=CLASSICAL
p:selector=PMIS
p:interpolator=D2
p:strength=AHAT
p:strength_threshold=0.25
smoother:relaxation_factor=0.8
s:print_config=1
s:print_solve_stats=1
s:obtain_timings=1
s:store_res_history=1
s:monitor_residual=1
s:max_iters=10000

Matrix Data

Constant symmetric matrix

Reproduction steps

Additional context

The MPI library is Cuda-Aware (I check it).

Add any other context about the problem here.

Start by reproducing the supplied AMGX 2.5.0 configuration with the constant symmetric matrix, comparing MPI_Direct timing during setup and solve. Check the result with the stated CUDA-aware MPI environment and the enabled timing output; done means the observed lack of solve-time benefit is explained or the issue is characterized with reproducible measurements.