  Porting codes to GPU often requires major efforts. While several tools exist
for automatically offload numerical libraries such as BLAS and LAPACK, they
often prove impractical due to the high cost of mandatory data transfer. The
new unified memory architecture in NVIDIA Grace-Hopper allows high bandwidth
cache-coherent memory access of all memory from both CPU and GPU, potentially
eliminating bottleneck faced in conventional architecture. This breakthrough
opens up new avenues for application development and porting strategies. In
this study, we introduce a new tool for automatic BLAS offload, the tool
leverages the high speed cache coherent NVLink C2C interconnect in
Grace-Hopper, and enables performant GPU offload for BLAS heavy applications
with no code changes or recompilation. The tool was tested on two quantum
chemistry or physics codes, great performance benefits were observed.
