Re: [dpdk-dev] [PATCH 2/8] trace: simplify trace point registration

[Thomas Monjalon <thomas@monjalon.net>]

05/05/2020 18:46, Jerin Jacob:
> On Tue, May 5, 2020 at 9:58 PM David Marchand <david.marchand@redhat.com> wrote:
> > On Tue, May 5, 2020 at 5:25 PM Jerin Jacob <jerinjacobk@gmail.com> wrote:
> > > On Tue, May 5, 2020 at 5:56 PM Jerin Jacob <jerinjacobk@gmail.com> wrote:
> > > > On Tue, May 5, 2020 at 5:06 PM David Marchand <david.marchand@redhat.com> wrote:
> > > > > On Tue, May 5, 2020 at 12:13 PM Jerin Jacob <jerinjacobk@gmail.com> wrote:
> > > > > > > > Please share the data.
> > > > > > >
> > > > > > > Measured time between first rte_trace_point_register and last one with
> > > > > > > a simple patch:
> > > > > >
> > > > > > I will try to reproduce this, once we finalize on the above synergy
> > > > > > with rte_log.
> > > > >
> > > > > I took the time to provide measure but you won't take the time to look at this.
> > > >
> > > > I will spend time on this. I would like to test with a shared library
> > > > also and more tracepoints.
> > > > I was looking for an agreement on using the constructor for rte_log as
> > > > well(Just make sure the direction is correct).
> > > >
> > > > Next steps:
> > > > - I will analyze the come back on this overhead on this thread.
> > >
> > > I have added 500 constructors for testing the overhead with the shared
> > > build and static build.
> > > My results inline with your results aka negligible overhead.
> > >
> > > David,
> > > Do you have plan for similar RTE_LOG_REGISTER as mentioned earlier?
> > > I would like to have rte_log and rte_trace semantics similar to registration.
> > > If you are not planning to submit the rte_log patch then I can send
> > > one for RC2 cleanup.
> >
> > It won't be possible for me.
> 
> I can do that if we agree on the specifics.
> 
> 
> >
> > Relying on the current rte_log_register is buggy with shared builds,
> > as drivers are calling rte_log_register, then impose a default level
> > without caring about what the user passed.
> > So if we introduce a RTE_LOG_REGISTER macro now at least this must be fixed too.
> >
> > What I wanted to do:
> > - merge rte_log_register_and_pick_level() (experimental) into
> > rte_log_register, doing this should be fine from my pov,
> > - reconsider the relevance of a fallback logtype when registration fails,
> > - shoot the default level per component thing: levels meaning is
> > fragmented across the drivers/libraries because of it, but this will
> > open a big box of stuff,
> 
> This you are referring to internal implementation improvement. Right?
> I was referring to remove the current clutter[1]
> If we stick the following as the interface. Then you can do other
> improvements when you get time
> that won't change the consumer code or interference part.
> 
> #define RTE_LOG_REGISTER(type, name, level)

This discussion is interesting but out of scope for rte_trace.
I am also interested in rte_log registration cleanup,
but I know it is too much work for the last weeks of 20.05.

As Olivier said about rte_trace,
"Since it's a new API, it makes sense to make
it as good as possible for the first version."

So please let's conclude on this rte_trace patch for 20.05-rc2,
and commit to fix rte_log registration in the first days of 20.08.