The BTF file format, more than just debugging
summary
BTF starts as a compact way to encode C types by converting DWARF via pahole into BTF as compact ELF section and now adds line numbers, original BPF bytecode and JIT info; libbpf, perf, bcc and bpftrace use it to pretty-print maps, validate types and associate metadata; recent toolchain work means clang emits BTF and pahole can generate it; Facebook prototypes combine all kernel CUs into one payload claiming 97x size reduction; kernel validates BTF and tooling uses it to enable portable BPF tracing while bailing out on incompatible changes.
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chapters (11)
- 0:00BPF observability challenges
- 1:53Introduction to BTF
- 4:40Using BTF for maps
- 7:57Filtering with BPF
- 12:16Dumping map contents
- 13:55Generating BTF information
- 19:21BTF loading and validation
- 22:52Compressing kernel debug info
- 25:41BTF for portable BPF
- 27:48New kernel tracing events
- 30:21Future developments and Q&A
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