Each data stream in a backup job is individually tracked by data agent(s) and media agent(s) in its path, generating performance data packets in-process and merging them into the processed data stream. The data stream thus incrementally accumulates performance data packets from any number of successive backup processes. The in-process tracking also captures hierarchical relationships among backup processes and in-process subtending tasks, so that the resulting performance report can depict parent and child operations. The hierarchical relationships are embedded into the performance data packets and may be analyzed by parsing the data stream. The media agent transfers the data packets belonging to the secondary copy to secondary storage. The media agent analyzes the performance data packets in the data stream and generates a performance report, which covers the data stream from source to destination, based on the accumulated information carried by the performance data packets. The media agent illustratively stores the performance report locally as a flat file.