Re: [PATCH v2 09/15] perf ftrace: add support for tracing option 'func_stack_trace'

[Changbin Du]

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@xxxxxxxxx> 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@xxxxxxxxx>

-- 
Cheers,
Changbin Du