The tool is divided into 3 parts, the first part, the spy_module runs in the kernel world, it collects the data; the second part, the spy_server runs in the user world, it receives results from the spy_module and communicates them to the third part, the third part is the spy_client, it has a tcl-tk graphical interface.
The monitoring tool was conceived to observe the behaviour of the linux hierarchical (or classfull) qdisc. The main idea behind the data acquisition is that the queues are in the leaf qdiscs, that means the gathering of all the data at the leaf level will give exhaustive information on the hierarchical qdisc behaviour.
The results are displayed for each leaf, a leaf having an identification as following: "interface-name qdisc-ident" example: "eth0 2:0" the qdisc-ident displayed is the leaf qdisc handle of the kernel, see the screenshot.