linux-kernel - Re: [PATCH 1/5] ftrace perf: Check sample types only for sampling events

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Date:	Tue, 15 Mar 2016 22:51:24 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Jiri Olsa <jolsa@...nel.org>, lkml <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Arnaldo Carvalho de Melo <acme@...nel.org>
Subject: Re: [PATCH 1/5] ftrace perf: Check sample types only for sampling
 events

On Tue, Mar 15, 2016 at 04:06:46PM -0400, Steven Rostedt wrote:
> On Wed,  9 Mar 2016 21:46:41 +0100
> Jiri Olsa <jolsa@...nel.org> wrote:
> 
> > Currently we check sample type for ftrace:function event
> > even if it's not created as sampling event. That prevents
> > creating ftrace_function event in counting mode.
> > 
> > Making sure we check sample types only for sampling events.
> > 
> > Before:
> >   $ sudo perf stat -e ftrace:function ls
> >   ...
> > 
> >    Performance counter stats for 'ls':
> > 
> >      <not supported>      ftrace:function
> > 
> >          0.001983662 seconds time elapsed
> > 
> > After:
> >   $ sudo perf stat -e ftrace:function ls
> 
> I'm assuming you gave yourself admin capabilities, and not any normal
> user may sample function tracing, right?

right ;-)

jirka