Re: [PATCH v1 1/3] libtracefs: Add user_events to libtracefs sources

[Steven Rostedt <rostedt@goodmis.org>]

On Tue, 22 Feb 2022 08:27:31 +0200
Yordan Karadzhov <y.karadz@gmail.com> wrote:

> I have one last question. Do you consider as a valid use case that
> the library must support, someone to do a just 'test" without writing
> after this, or to "write" without testing first?

Actually, that's a very good point.

I was thinking that I didn't like the "test" name, and was thinking of
having it be:

	if (tracefs_user_event_enabled(event)) {
		tracefs_user_event_record(event, ...);
	}

But I think you have a good point. Perhaps we should just have:

	tracefs_user_event_trace(event, ...);

and it do all the work. But it would need to be a macro, that does:

#define tracefs_user_event_trace(event, ...)			\
	do {							\
		if (tracefs_user_event_enabled(event)) {	\
			tracefs_user_event_record(event, ##__VA_ARGS); \
		}						\
	} while (0)

Because we do not want to have the compiler process the arguments when
the event is not enabled. That would be too much overhead.

But as a macro, it would work.

Thoughts?

-- Steve