> Is DWARF unwinding so slow that that is actually faster?
No. The only reason it works like this is because the upstream Linux kernel has thus far rejected in-kernel dwarf unwinders, but copying the stack is simpler and available / implemented.
No. The only reason it works like this is because the upstream Linux kernel has thus far rejected in-kernel dwarf unwinders, but copying the stack is simpler and available / implemented.
The elephant in the room btw is LBR call stacks, but they aren't exposed in the kernel/BPF yet. Userland perf has them and they recently became available on AMD.
> Why not implement your approach and mail it to LKML :-)
because this would still be an in-kernel dwarf unwinder and I would expect an instant reject, and because I am lazy and/or don’t care enough about this problem or linux to work on it. Even if people could be persuaded, I don’t have the interest or temperance to debate this with LKML.