SpurTracer is a push-notification based monitoring solution for heterogenous loosely coupled IT infrastructures. It complements a service-endpoint monitoring solution like Nagios with a component-level interface auto-discovery. It automatically provides a certain level of functional tracing along with many non-functional measurements (e.g. call, error and timeout rates, interface latency, component execution, etc.). While being zero config itself, SpurTracer relies on you adding push notification support to the components you want to monitor. The best way to use SpurTracer is by adding punctual tracing to components in your infrastructure on-demand.
x11vis is a visual and interactive tool for debugging X11 clients. Unlike other tools such as xtrace, it displays human readable IDs on all requests, no matter at which point in time the information becomes available. To help you cope with large amounts of data, it displays only the most important information by default, automatically folds sequences of boring requests, allows you to filter by packet type or client, and provides markers for navigation. Instead of assigning a number to each connection, it displays the command line with which that client was started.