RE: [PATCH v4] eal: add build-time option to omit trace

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Jerin Jacob [mailto:jerinjacobk@gmail.com]
> Sent: Tuesday, 1 October 2024 17.02
> 
> On Tue, Oct 1, 2024 at 7:44 PM Morten Brørup <mb@smartsharesystems.com>
> wrote:
> >
> > > From: Jerin Jacob [mailto:jerinjacobk@gmail.com]
> > > Sent: Tuesday, 1 October 2024 16.05
> > >
> > > On Tue, Oct 1, 2024 at 7:19 PM Morten Brørup
> <mb@smartsharesystems.com>
> > > wrote:
> > > >
> > > > Jerin,
> > > >
> > > > If you have no further comments, please add review/ack tag, to
> help
> > > Thomas see that the patch has been accepted by the maintainer, and
> can
> > > be merged.
> > >
> > > There was a comment to make the function as rte_trace_is_enabled()
> and
> > > remove internal. The rest looks good to me. I will Ack in the next
> > > version.
> >
> > Perhaps my reply to that comment was unclear... such a public
> function already exists in the previous API:
> 
> I see. It was not clear.
> 
> >
> https://elixir.bootlin.com/dpdk/v24.07/source/lib/eal/include/rte_trace
> .h#L36
> >
> > That function tells if trace enabled at both build time and runtime,
> and returns false if not.
> >
> > A separate public function to tell if trace is enabled at build time
> seems like overkill to me. Is that what you are asking for?
> 
> No. Just use rte_trace_is_enabled() in app/test instead of
> __rte_trace_point_generic_is_enabled() as it is internal.

Just tested it, and it didn't have the wanted effect.
I think rte_trace_is_enabled() returns false until at least one tracepoint has been enabled, which seems like a good optimization.
But it also means that we cannot use it to replace __rte_trace_point_generic_is_enabled() in test/app, because no tracepoints have been enabled at this point of execution, so it returns false here.

I looked around in the code, and cannot find a method without looking at internals, or duplicating a test case.

I could test if rte_trace_point_lookup("app.dpdk.test.tp") returns non-NULL, but that would duplicate the same test in test_trace_points_lookup().

What do you think...
Keep using internal function __rte_trace_point_generic_is_enabled(),
test rte_trace_point_lookup("app.dpdk.test.tp") != NULL,
or any other idea?