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


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@redhat.com>
>>>
>>> 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@kdab.com>
>>> Based-on-patch-by: Milian Wolff <milian.wolff@kdab.com>
>>> Link: http://lkml.kernel.org/n/tip-lmtbeqm403f3luw4jkjevsi5@git.kernel.org
>>> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
>>> ---
>>> 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@kdab.com>
> Based-on-patch-by: Milian Wolff <milian.wolff@kdab.com>
> Link: http://lkml.kernel.org/n/tip-lmtbeqm403f3luw4jkjevsi5@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>

This time behavior is not changed. Thank you.

Tested-by: Wang Nan <wangnan0@huawei.com>




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