Re: Feedback on: [RESEND PATCH v2 0/5] perf report: Show inline stack

[Milian Wolff <milian.wolff@kdab.com>]

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On Monday, January 9, 2017 4:17:48 PM CET Jin, Yao wrote:
> Hi Wolff,
> 
> Thanks a lot for your test code!
> 
> I have updated my patch. The new output for your test code (binary name
> is inline) is:
> 
> # Overhead  Command  Shared Object        Symbol
> # ........  .......  ................... ..................................
> #
>      56.76%  inline   inline               [.] main
> 
>              ---main
>                 __libc_start_main
>                 _start
> 
>      40.54%  inline   libm-2.23.so         [.] __hypot_finite
> 
>              ---__hypot_finite
> 
>                  --40.09%--__hypot
>                            main
>                            __libc_start_main
>                            _start
> 
>       1.30%  inline   libm-2.23.so         [.] __hypot
> 
>              ---__hypot
>                 main
> 
>                 ---/usr/include/c++/5/bits/random.h:151 (inline)
>                    /usr/include/c++/5/bits/random.h:332 (inline)
>                    /usr/include/c++/5/bits/random.tcc:3328 (inline)
>                    /usr/include/c++/5/bits/random.h:185 (inline)
>                    /usr/include/c++/5/bits/random.h:1818 (inline)
>                    /usr/include/c++/5/bits/random.h:1809 (inline)
> /home/jinyao/skl-ws/perf-dev/lck-2867/test/inline.cpp:14 (inline)
>                 __libc_start_main
>                 _start
> 
> The inline entry is tagged with "(inline)". Is this result within
> expectation?

No, this is not the expected output. I expect to get information about the 
inlined frames in the middle of the call stack, in this example that happens 
for the first two major hotspots.

Below is the output from my approach to this problem using my -g srcline:

~~~~~~~~~~~~~~ pasted here for readability: https://paste.kde.org/pmq3bc1le
Samples: 149  of event 'cycles:ppp', Event count (approx.): 141334499
  Overhead  Command  Shared Object     Symbol
-   62.24%  inline   inline            [.] main
   - 27.98% std::generate_canonical<double, 53ul, 
std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> > 
random.tcc:3332
        std::__detail::_Adaptor<std::linear_congruential_engine<unsigned long, 
16807ul, 0ul, 2147483647ul>, double>::operator() random.h:185
        std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned 
long, 16807ul, 0ul, 2147483647ul> > random.h:1818
        std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned 
long, 16807ul, 0ul, 2147483647ul> > random.h:1809
        main ine.cpp:14
        __libc_start_main +241
        _start +4194346
   - 25.88% std::__detail::_Mod<unsigned long, 2147483647ul, 16807ul, 0ul, 
true, true>::__calc random.h:143
        std::__detail::__mod<unsigned long, 2147483647ul, 16807ul, 0ul> 
random.h:151
        std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 
2147483647ul>::operator() random.h:332
        std::generate_canonical<double, 53ul, 
std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> > 
random.tcc:3332
        std::__detail::_Adaptor<std::linear_congruential_engine<unsigned long, 
16807ul, 0ul, 2147483647ul>, double>::operator() random.h:185
        std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned 
long, 16807ul, 0ul, 2147483647ul> > random.h:1818
        std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned 
long, 16807ul, 0ul, 2147483647ul> > random.h:1809
        main ine.cpp:14
        __libc_start_main +241
        _start +4194346
   + 4.14% main inline.cpp:13
   + 2.89% 
std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned 
long, 16807ul, 0ul, 2147483647ul> > random.h:1818
   + 0.68% std::_Norm_helper<true>::_S_do_it<double> complex:655
   + 0.67% std::generate_canonical<double, 53ul, 
std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> > 
random.tcc:3326
-   26.24%  inline   libm-2.24.so      [.] __hypot_finite
   - __hypot_finite +179
      - 25.56% hypot +20
           std::__complex_abs complex:589
           std::abs<double> complex:597
           std::_Norm_helper<true>::_S_do_it<double> complex:654
           std::norm<double> complex:664
           main ine.cpp:14
           __libc_start_main +241
           _start +4194346
        0.68% 0x40ead238ed1a2cf4
-    6.85%  inline   libm-2.24.so      [.] hypot
     hypot +40
     std::__complex_abs complex:589
     std::abs<double> complex:597
     std::_Norm_helper<true>::_S_do_it<double> complex:654
     std::norm<double> complex:664
     main ine.cpp:14
     __libc_start_main +241
     _start +4194346
~~~~~~~~~~~~~~

I hope you see the value of such a report versus what you are proposing.

Thanks

-- 
Milian Wolff | milian.wolff@kdab.com | Software Engineer
KDAB (Deutschland) GmbH&Co KG, a KDAB Group company
Tel: +49-30-521325470
KDAB - The Qt Experts

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