Re: [PATCH dwarves v2 07/10] btf_encoder: introduce btf_encoding_context

[Eduard Zingerman <eddyz87@gmail.com>]

On Tue, 2024-12-17 at 16:03 -0800, Andrii Nakryiko wrote:

[...]

> I agree with Ihor. I think he invested a lot of time into these
> improvements, and asking him to re-do the series just to shuffle a few
> patches around is just an unnecessary overhead (which also delays the
> ultimate outcome: faster BTF generation with pahole).

Patches #1-4 are good refactorings.
Patches #5-7 introduce a global state and complication where this
could be avoided. (These were necessary before Ihor figured out the
trick with patch #10).
E.g. 'elf_functions_list':
- there is no reason for it to be global, it could be a part of the
  encoder, as it is now;
- there is no reason for it to be a list, encoding works with a single
  function table and keeping it as a list just confuses reader.

Same for btf_encoder_list_lock / btf_encoder_list.

> And as Ihor mentioned, we might improve upon this series by
> parallelizing encoders to gain some further improvements, so I think
> all the internal refactoring and preparations are setting up a good
> base for further work.

Not really, the main insight found by Ihor is that parallel BTF
encoding doesn't make much sense: constructing BTF is as cheap as
copying it. I don't see much room for improvement here.

[...]