On Tue, Feb 18, 2020 at 11:02 AM Michal Rostecki [off-list ref] wrote:

This patch series extend the "bpftool feature" subcommand with the
new positional arguments:

- "section", which allows to select a specific section of probes (i.e.
  "system_config", "program_types", "map_types");
- "filter_in", which allows to select only probes which matches the
  given regex pattern;
- "filter_out", which allows to filter out probes which do not match the
  given regex pattern.

The main motivation behind those changes is ability the fact that some
probes (for example those related to "trace" or "write_user" helpers)
emit dmesg messages which might be confusing for people who are running
on production environments. For details see the Cilium issue[0].

[0] https://github.com/cilium/cilium/issues/10048

The motivation is clear, but I think the users shouldn't be made
aware of such implementation details. I think instead of filter_in/out
it's better to do 'full or safe' mode of probing.
By default it can do all the probing that doesn't cause
extra dmesgs and in 'full' mode it can probe everything.