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Tutorial: advanced BTF example
It didn't merge this branch with BTF examples as it failed...
It believe it now actually works, as it was a issue in libbpf that caused the BTF code to get rejected on load.
Jesper Dangaard Brouer [email protected] writes:
It didn't merge this branch with BTF examples as it failed...
It believe it now actually works, as it was a issue in libbpf that caused the BTF code to get rejected on load. You can view, comment on, or merge this pull request online at:
So no issue on the kernel side? We are currently recommending people to use 4.20 or higher when running the tutorial...
BTF in the kernel tree have moved away from BPF_ANNOTATE_KV_PAIR define system (which is used in this PR branch)
In kernel v5.5 it will be placed in: tools/testing/selftests/bpf/bpf_legacy.h
- Changed by @anakryiko in commit 36b5d471135c
We should instead have a tutorial that uses the new BTF method... but AFAIK it depends on LLVM version 9, which is not adopted by many distros ...yet.
Yeah, the lack of LLVM9 is a problem; we also want to use the new BTF syntax for map pinning. Should we just tell people to install it? :)
@tohojo, with LLVM9 you also won't need pahole for BTF generation, so that's a double win: you can get rid of a good chunk of sample Makefile ;)
In lack of places to put this, let me link a really advanced example by @chaudron https://lore.kernel.org/bpf/[email protected]/
We unfortunately have to wait for a LLVM release to use this in the tutorial...
My plan is to drop this PR, and create a new one based on LLVM9 and use the new ELF-maps style as an example. I also want to detect the LLVM version, to give users a more clear expectations when compiling the example.
Jesper Dangaard Brouer [email protected] writes:
My plan is to drop this PR, and create a new one based on LLVM9 and use the new ELF-maps style as an example. I also want to detect the LLVM version, to give users a more clear expectations when compiling the example.
SGTM