Re: [PATCHv2 2/3] perf tools: Add callchain order support for libunwind DWARF unwinder

[Wangnan (F)]

On 2015/11/18 15:52, Jiri Olsa wrote:
> On Wed, Nov 18, 2015 at 12:13:08PM +0800, Wangnan (F) wrote:
> > On 2015/11/17 23:05, Jiri Olsa wrote:
> > > From: Jiri Olsa <jolsa@xxxxxxxxxx>
> > >
> > > As reported by Milian, currently for DWARF unwind (both libdw
> > > and libunwind) we display callchain in callee order only.
> > >
> > > Adding the support to follow callchain order setup to libunwind
> > > DWARF unwinder, so we could get following output for report:
> > >
> > >    $ perf record --call-graph dwarf ls
> > >    ...
> > >    $ perf report --no-children --stdio
> > >
> > >      39.26%  ls       libc-2.21.so      [.] __strcoll_l
> > >                   |
> > >                   ---__strcoll_l
> > >                      mpsort_with_tmp
> > >                      mpsort_with_tmp
> > >                      sort_files
> > >                      main
> > >                      __libc_start_main
> > >                      _start
> > >                      0
> > >
> > >    $ perf report -g caller --no-children --stdio
> > >      ...
> > >      39.26%  ls       libc-2.21.so      [.] __strcoll_l
> > >                   |
> > >                   ---0
> > >                      _start
> > >                      __libc_start_main
> > >                      main
> > >                      sort_files
> > >                      mpsort_with_tmp
> > >                      mpsort_with_tmp
> > >                      __strcoll_l
> > >
> > > Reported-by: Milian Wolff <milian.wolff@xxxxxxxx>
> > > Based-on-patch-by: Milian Wolff <milian.wolff@xxxxxxxx>
> > > Link: http://lkml.kernel.org/n/tip-lmtbeqm403f3luw4jkjevsi5@xxxxxxxxxxxxxx
> > > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > > ---
> > >   tools/perf/util/unwind-libunwind.c | 47 ++++++++++++++++++++++++--------------
> > >   1 file changed, 30 insertions(+), 17 deletions(-)
> > >
> > > diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
> > > index 0ae8844fe7a6..705e1c19f1ea 100644
> > > --- a/tools/perf/util/unwind-libunwind.c
> > > +++ b/tools/perf/util/unwind-libunwind.c
> > [SNIP]
> >
> > > -		unw_get_reg(&c, UNW_REG_IP, &ip);
> > > -		ret = ip ? entry(ip, ui->thread, cb, arg) : 0;
> > In original code if ip == 0 entry() won't be called.
> >
> > > +		if (callchain_param.order == ORDER_CALLER)
> > > +			j = max_stack - i - 1;
> > > +		ret = entry(ips[j], ui->thread, cb, arg);
> ouch.. the intention was not to breake current behaviour ;-)
>
> v2 is attached, it's also in perf/callchain_2 branch
>
> thanks,
> jirka
>
>
> ---
> As reported by Milian, currently for DWARF unwind (both libdw
> and libunwind) we display callchain in callee order only.
>
> Adding the support to follow callchain order setup to libunwind
> DWARF unwinder, so we could get following output for report:
>
>    $ perf record --call-graph dwarf ls
>    ...
>    $ perf report --no-children --stdio
>
>      39.26%  ls       libc-2.21.so      [.] __strcoll_l
>                   |
>                   ---__strcoll_l
>                      mpsort_with_tmp
>                      mpsort_with_tmp
>                      sort_files
>                      main
>                      __libc_start_main
>                      _start
>                      0
>
>    $ perf report -g caller --no-children --stdio
>      ...
>      39.26%  ls       libc-2.21.so      [.] __strcoll_l
>                   |
>                   ---0
>                      _start
>                      __libc_start_main
>                      main
>                      sort_files
>                      mpsort_with_tmp
>                      mpsort_with_tmp
>                      __strcoll_l
>
> Reported-by: Milian Wolff <milian.wolff@xxxxxxxx>
> Based-on-patch-by: Milian Wolff <milian.wolff@xxxxxxxx>
> Link: http://lkml.kernel.org/n/tip-lmtbeqm403f3luw4jkjevsi5@xxxxxxxxxxxxxx
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>

This time behavior is not changed. Thank you.

Tested-by: Wang Nan <wangnan0@xxxxxxxxxx>


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