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Message-ID: <20141113172506.GB22994@krava.redhat.com>
Date: Thu, 13 Nov 2014 18:25:07 +0100
From: Jiri Olsa <jolsa@...hat.com>
To: Jiri Olsa <jolsa@...nel.org>
Cc: linux-kernel@...r.kernel.org,
Arnaldo Carvalho de Melo <acme@...hat.com>,
Corey Ashford <cjashfor@...ux.vnet.ibm.com>,
David Ahern <dsahern@...il.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Paul Mackerras <paulus@...ba.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH] perf tools: Fix ftrace:function event recording
On Thu, Nov 13, 2014 at 06:21:03PM +0100, Jiri Olsa wrote:
> Following patch fails (-EINVAL) ftrace:function with enabled user
> space callchains:
> cfa77bc4af2c perf: Disallow user-space callchains for function trace events
>
> We need to follow in perf tool itself and explicitly set the
> perf_event_attr::exclude_callchain_user flag for ftrace:function
> event.
forgot:
Reported-by: Steven Rostedt <rostedt@...dmis.org>
thanks,
jirka
>
> Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
> Cc: Corey Ashford <cjashfor@...ux.vnet.ibm.com>
> Cc: David Ahern <dsahern@...il.com>
> Cc: Frederic Weisbecker <fweisbec@...il.com>
> Cc: Ingo Molnar <mingo@...nel.org>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Paul Mackerras <paulus@...ba.org>
> Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
> Cc: Steven Rostedt <rostedt@...dmis.org>
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
> tools/perf/util/evsel.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index ec5eb8033296..a3baaa31231e 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -658,6 +658,14 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts)
> attr->mmap_data = track;
> }
>
> + /*
> + * We don't allow user space callchains for function trace
> + * event, due to issues with page faults while tracing page
> + * fault handler and its overall trickiness nature.
> + */
> + if (perf_evsel__is_function_event(evsel))
> + evsel->attr.exclude_callchain_user = 1;
> +
> if (callchain_param.enabled && !evsel->no_aux_samples)
> perf_evsel__config_callgraph(evsel);
>
> --
> 1.9.3
>
--
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