Spark/Databricks: GPU does not appear to be utilized for ML regression (cross-validation, prediction) notebook
Spark itself does not use GPUs at all, so this is not surprising.

The operations it performs are at best L3 BLAS ops of moderate size, and most are small L1 operations, so generally a GPU isn't a win. It does use BLAS to accelerate those ops in hardware if a BLAS library like MKL or OpenBLAS is present.