Re: [RFC PATCH 2/3] tracing: Introduce "rel_stack" option

[Steven Rostedt]

On Wed, 29 Jan 2025 00:37:15 +0900
"Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> 
> Since the relative offset stacktrace requires a special module loading
> events to decode binary, it should be an optional for normal use case.
> User can enable this feature via `options/relative-stacktrace`.
> 

Let's make this an entirely new event and not based on an option. Reason
being, there's no way for libtraceevent to know which this is. We could
even have a mixture of these in the trace.

Instead of an option, we can add a new trigger: stacktrace_rel that will do
a relative stack trace. And the event can be kernel_stack_rel

Then it can be enabled via:

  echo 'stacktrace_rel if prev_state & 3' > events/sched/sched_switch/trigger

-- Steve