Re: [PATCH 0/4] tracing: improve symbolic printing

On 04/10/2023 18:29, Steven Rostedt wrote:

On Wed, 4 Oct 2023 09:54:31 -0700
Jakub Kicinski [off-list ref] wrote:

quoted

On Wed, 4 Oct 2023 12:35:24 -0400 Steven Rostedt wrote:

quoted

quoted

Potentially naive question - the trace point holds enum skb_drop_reason.
The user space can get the names from BTF. Can we not teach user space
to generically look up names of enums in BTF?    

That puts a hard requirement to include BTF in builds where it was not
needed before. I really do not want to build with BTF just to get access to
these symbols. And since this is used by the embedded world, and BTF is
extremely bloated, the short answer is "No".  

Dunno. BTF is there most of the time. It could make the life of
majority of the users far more pleasant.

BTF isn't there for a lot of developers working in embedded who use this
code. Most my users that I deal with have minimal environments, so BTF is a
showstopper.

One thing we've heard from some embedded folks [1] is that having
kernel BTF loadable as a separate module (rather than embedded in
vmlinux) would help, as there are size limits on vmlinux that they can
workaround by having modules on a different partition. We're hoping
to get that working soon. I was wondering if you see other issues around
BTF adoption for embedded systems that we could put on the to-do list?
Not necessarily for this particular use-case (since there are
complications with trace data as you describe), but just trying to make
sure we can remove barriers to BTF adoption where possible.

Thanks!

Alan

[1]
https://lore.kernel.org/bpf/CAHBbfcUkr6fTm2X9GNsFNqV75fTG=aBQXFx_8Ayk+4hk7heB-g@mail.gmail.com/ (local)

quoted

I hope we can at least agree that the current methods of generating 
the string arrays at C level are... aesthetically displeasing.

I don't know, I kinda like it ;-)

-- Steve