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Date:   Tue, 7 Jul 2020 23:19:31 +0800
From:   Changbin Du <changbin.du@gmail.com>
To:     Namhyung Kim <namhyung@kernel.org>
Cc:     Changbin Du <changbin.du@gmail.com>, Jiri Olsa <jolsa@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 09/15] perf ftrace: add support for tracing option
 'func_stack_trace'
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 <CAM9d7ch7gPmen8TJ9PbiK-QnQ_ojGVGqbR3bGYT4AMNW3Odp+A@mail.gmail.com>
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On Fri, Jul 03, 2020 at 03:30:32PM +0900, Namhyung Kim wrote:
> On Sat, Jun 27, 2020 at 10:38 PM Changbin Du <changbin.du@gmail.com> wrote:
> >
> > This adds support to display call trace for function tracer. To do this,
> > just specify a '--func-call-graph' option.
> 
> What if it's used with -G option?  Also it might be used only with
> the -T option..  How about showing a warning if it's missing.. ?
>
All '--func-xxx' options are function tracer only. The warning message is a
good idea.

> Thanks
> Namhyung
> 
> >
> > $ sudo perf ftrace -T vfs_read --func-call-graph
> >  iio-sensor-prox-855   [003]   6168.369657: vfs_read <-ksys_read
> >  iio-sensor-prox-855   [003]   6168.369677: <stack trace>
> >  => vfs_read
> >  => ksys_read
> >  => __x64_sys_read
> >  => do_syscall_64
> >  => entry_SYSCALL_64_after_hwframe
> >  ...
> >
> > Signed-off-by: Changbin Du <changbin.du@gmail.com>

-- 
Cheers,
Changbin Du