Regressions of such magnitude can veto such changes, especially when
they hit everyone, not just those who are highly dependent on the
profiling tools the proposal is concerned about.
=== Alternatives to frame pointers ===
There are a few alternative ways to unwind stacks instead of using the
frame pointer:
* [
https://dwarfstd.org DWARF] data - The compiler can emit extra
[...] The problem is that we need to unwind the stack in kernel space
(Are you referring to a novel kernel-resident tool?)
To summarize, if we want complete stacks with reasonably low
overhead
(which we do, there's no other way to get accurate profiling data from
running services), frame pointers are currently the best option.
The proposal doesn't characterize the "reasonably low overhead" that
this operation targets. That makes it hard to judge the tradeoffs.
[...]
Fedora users will be more likely to have a streamlined experience when
trying to debug/profile system executables/libraries. Tools such as
perf will work out of the box instead of requiring to users to provide
extra options (e.g. --call-graph=dwarf/LBR) [...]
If typing that option were a hardship, it could be made default on
Fedora. With broad debuginfod auto-downloading capability, maybe it's
worth considering.
- FChE