Missing either libigdml.so.1 or libigdmd.so.1 causes unitrace's "[WARNING] No metrics found (status = 0x0) group_count = 0"

[kefeiyao]

Do "unitrace --metric-list" at the absense of libigdml.so.1 or libigdmd.so.1 and observe the result ([WARNING] No metrics found (status = 0x0) group_count = 0)
Libigdml and libigdmd are not required to run a workload which makes it possible to not have them within a runtime environment. But when a performance caring user wants to collect some metrics for a workload, they will be suprised here.
That would be more user friendly if clear indication is added to unitrace .md that metrics collection depends on both libigdml and libigdmd and/or dump useful information about possible reasons of getting 0 metric group.