I am getting "Unrecognized function or variable 'ddBlk'." error while creating performance plot of memory controller block

I need to create a performance plot for memory controller for bandwidth and latencies for model shown below:

I have logged all the signals in the model shown above. But when I am trying to create performace plot for the memory controller then I am getting error mentioned below:

Please help me to solve this issue or if some tutorials are available that explains in detail how to create performance plot for memory controller and memory channel then let me know