eBPF is an amazing technology that allows safely running user-supplied functions at pretty much arbitrary probe points in a kernel/user space context. Much has been written about how amazing this feature is for kernel observability. But as someone who writes user space code, what I find even more amazing is the support for tracing arbitrary user space programs, with no code changes and low overhead.

However, doing in-depth analysis can get complicated and time-consuming. My goal with wachy was to make this debugging significantly easier/faster to use, by displaying traces in a TUI next to the source code and allowing for interactive drilldown analysis. If you get a chance, check out the start of the demo video since (AFAIK) it's quite unique and gives a much clearer idea than I can provide with just text.