Darshan instrumentation on ThetaGPU is not automatically included into the binary like Theta. The user must set the LD_PRELOAD variable as part of running the job.
Logs will be generated in the directory: /lus/grand/logs/darshan/thetagpu/<YEAR>/<MONTH>/<DAY>
In order to view a log, use the darshan-parser utility.
module load darshan
mpirun ... -x LD_PRELOAD=$DARSHAN_PRELOAD
See the Theta documentation for more ALCF specific Darshan usage.