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@xxxxxxxxxxxxx> 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.
