Re: [PATCH 14/14] scripts/sorttable: ftrace: Do not add weak functions to available_filter_functions

Peter Zijlstra
2025-01-02T20:36:34Z

On Thu, Jan 02, 2025 at 03:30:16PM -0500, Steven Rostedt wrote:
> On Thu, 2 Jan 2025 21:24:04 +0100
> Peter Zijlstra <peterz@infradead.org> wrote:
>
> > It is not. If kallsyms is fixed, you can use that to tell which
> > fentry/mcount sites are 'invalid'.
>
> I can't use kallsyms for valid tests at boot up. Even with a binary search,
> it's still rather slow. The ftrace table is created at early boot, even
> before scheduling (it's needed before you can enable boot time function
> tracing), so any slow down in creating that table slows down the boot, and
> people will notice.

I'm not sure I understand, up until you've started userspace, nobody
cares about those weird indexes.