Re: [PATCH][RFC] tracing: Enable tracepoints via module parameters

[Mathieu Desnoyers]

----- On Apr 20, 2021, at 8:55 AM, rostedt rostedt@xxxxxxxxxxx wrote:
[...]
> 
> Would adding automatic module parameters be an issue? That is, you can add
> in the insmod command line a parameter that will enable tracepoints. We
> could have a way to even see them from the modinfo. I think I had that
> working once, and it wasn't really that hard to do.

There is one thing we should consider here in terms of namespacing: those module
command line parameters should be specific to each tracer (e.g. ftrace, perf, ebpf).

LTTng for instance already tackles early module load tracing in a different
way: users can enable instrumentation of yet-to-be loaded kernel modules. So
it would not make sense in that scheme to have module load parameters.

It's a different trade-off in terms of error reporting though: for instance,
LTTng won't report an error if a user does a typo when entering an event name.

So I think those command line parameters should be tracer-specific, do you agree ?

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com