linux-kernel - Re: [PATCH 3/3] perf-probe: Do not show the skipped events

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Date:   Fri, 24 Apr 2020 08:33:05 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        stable@...r.kernel.org
Subject: Re: [PATCH 3/3] perf-probe: Do not show the skipped events

On Thu, 23 Apr 2020 11:01:39 -0300
Arnaldo Carvalho de Melo <acme@...nel.org> wrote:

> Em Thu, Apr 23, 2020 at 08:01:22PM +0900, Masami Hiramatsu escreveu:
> > When a probe point is expanded to several places (like inlined) and
> > if some of them are skipped because of blacklisted or __init function,
> > those trace_events has no event name. It must be skipped while showing
> > results.
> > 
> > Without this fix, you can see "(null):(null)" on the list,
> > ===========
> 
> Ok, you broke the patch in two, I think its better to combine both, ok?

No, if an inlined function is embedded in blacklisted areas, it also
shows same "(null):(null)" without [2/3].

Reordering the patches is OK, but this is still an independent fix.

Thank you,

> 
> - Arnaldo
> 
> >   # ./perf probe request_resource
> >   reserve_setup is out of .text, skip it.
> >   Added new events:
> >     (null):(null)        (on request_resource)
> >     probe:request_resource (on request_resource)
> > 
> >   You can now use it in all perf tools, such as:
> > 
> >   	perf record -e probe:request_resource -aR sleep 1
> > 
> > ===========
> > 
> > With this fix, it is ignored.
> > ===========
> >   # ./perf probe request_resource
> >   reserve_setup is out of .text, skip it.
> >   Added new events:
> >     probe:request_resource (on request_resource)
> > 
> >   You can now use it in all perf tools, such as:
> > 
> >   	perf record -e probe:request_resource -aR sleep 1
> > 
> > ===========
> > 
> > Fixes: 5a51fcd1f30c ("perf probe: Skip kernel symbols which is out of .text")
> > Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
> > Cc: stable@...r.kernel.org
> > ---
> >  tools/perf/builtin-probe.c |    3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
> > index 70548df2abb9..6b1507566770 100644
> > --- a/tools/perf/builtin-probe.c
> > +++ b/tools/perf/builtin-probe.c
> > @@ -364,6 +364,9 @@ static int perf_add_probe_events(struct perf_probe_event *pevs, int npevs)
> >  
> >  		for (k = 0; k < pev->ntevs; k++) {
> >  			struct probe_trace_event *tev = &pev->tevs[k];
> > +			/* Skipped events have no event name */
> > +			if (!tev->event)
> > +				continue;
> >  
> >  			/* We use tev's name for showing new events */
> >  			show_perf_probe_event(tev->group, tev->event, pev,
> > 
> 
> -- 
> 
> - Arnaldo


-- 
Masami Hiramatsu <mhiramat@...nel.org>