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Date:   Thu, 10 Jun 2021 22:47:41 +0200
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
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References: <20210610060643.595673-1-irogers@google.com>
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 <YMJjMPDKo2IdCC6G@krava>
 <20210610155915.20a252d3@oasis.local.home>
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On Thu, Jun 10, 2021 at 03:59:15PM -0400, Steven Rostedt wrote:
> On Thu, 10 Jun 2021 21:08:32 +0200
> Jiri Olsa <jolsa@redhat.com> wrote:
> 
> > 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.
> 
> Or it can also be changed to export the version too?
> 
> LIBTRACEEVENT_VERSION = $(shell pkg-config --modversion libtraceevent | perl -e '$ver=<>; @v=split /,/,$ver; printf "%d\n", $v[0] * 255 * 255 | $v[1] * 255 | $v[2];')
> 
> -DLIBTRACEFS_VERSION=$(LIBTRACEEVENT_VERSION)

so the feature detection just gives out on/off answers,
but we can easily put above to perf's makefile

jirka

> 
> Then in C have:
> 
> #define VERSION(a,b,c) ((a)*255*255|(b)*255|(c))
> 
> #if LIBTRACEEVENT_VERSION >= VERSION(1,2,3)
> 
> To test if the libtraceevent feature is available?
> 
> -- Steve
>