Re: [RFC PATCH] libtraceevent: Increase libtraceevent logging when verbose

From: Jiri Olsa <jolsa@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Ian Rogers <irogers@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Namhyung Kim <namhyung@kernel.org>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-trace-users@vger.kernel.org,
	Tzvetomir Stoyanov <tz.stoyanov@gmail.com>,
	eranian@google.com, Michael Petlan <mpetlan@redhat.com>
Subject: Re: [RFC PATCH] libtraceevent: Increase libtraceevent logging when verbose
Date: Thu, 10 Jun 2021 21:08:32 +0200	[thread overview]
Message-ID: <YMJjMPDKo2IdCC6G@krava> (raw)
In-Reply-To: <20210610103927.44462e35@oasis.local.home>

On Thu, Jun 10, 2021 at 10:39:27AM -0400, Steven Rostedt wrote:
> On Wed,  9 Jun 2021 23:06:43 -0700
> Ian Rogers <irogers@google.com> wrote:
> 
> > libtraceevent has added more levels of debug printout and with changes
> > like:
> > https://lore.kernel.org/linux-trace-devel/20210507095022.1079364-3-tz.stoyanov@gmail.com
> > previously generated output like "registering plugin" is no longer
> > displayed. This change makes it so that if perf's verbose debug output
> > is enabled then the debug and info libtraceevent messages can be
> > displayed.
> > As this API isn't present in the deprecated tools version of
> > libtracevent I'm uploading this as an RFC.
> 
> Thanks Ian,
> 
> We need to start porting perf to using the upstream libtraceevent
> library. I think the best way to do that is what we did with trace-cmd.
> That is to have the make files check if the minimum version of
> libtraceevent is installed, and if so, use that instead of the local
> version. If it is not installed, produce a message encouraging the
> developer to install the upstream libtraceevent and warn that it will
> be using a deprecated older versino, then build the deprecated local
> version. After some time, we could simply remove it and make it a
> dependency, but I want to do that when all the main distros being used
> have it.

Michael did the libtraceevent detection and dynamic linking support:
  https://lore.kernel.org/linux-perf-users/20210428092023.4009-1-mpetlan@redhat.com/

I think we should have that in Fedora/RHEL rpms already, or it's on the way.

The detection code could be change to contain things we need.

jirka

> 
> Currently its in the latest Debian, Ubuntu, and Fedora. I also believe
> its in SUSE but have not checked. It's in Fedora 34, but it doesn't
> appear to be in Fedora 33. As that's not too old, I don't think we
> should make it a dependency as of yet.
> 
> -- Steve
> 