Concepts

The Guide tells you what to type. These pages explain how stax works — enough that, when something is missing from a profile or a number looks off, you know where to look.

• Architecture — the three processes, what staxd does on each platform, and the sockets between them
• Platform Support — what macOS and Linux each capture, and what they don't
• Stack Unwinding — frame pointers, DWARF .eh_frame, and what your build needs
• Sampling — what a profiler actually measures, on-CPU and off-CPU
• Symbolication — turning raw addresses into names: symbol tables, debuginfod, the dyld shared cache
• Target Observability Roadmap — the plan for target lanes, origins, sources, attachments, counters, and critical-path views

If you only read one, read Stack Unwinding — on macOS a build without frame pointers produces a profile with no call stacks, and that surprises people.