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Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling taken at 'callq' instruction

From Jiri Olsa <jolsa@redhat.com>
Newsgroups linux.kernel
Subject Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling taken at 'callq' instruction
Date 2015-11-18 09:50 +0100
Message-ID <qw6Bc-vx-11@gated-at.bofh.it> (permalink)
References <qw5lL-8cX-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Wed, Nov 18, 2015 at 03:20:36PM +0800, Wangnan (F) wrote:

SNIP

> 
> Then use perf to trace it:
> 
> # ./pref record  -g -F 9 --call-graph dwarf ./test_dwarf_unwind
> # ./perf report  --no-children --stdio
>      ...
>      1.23%  test_dwarf_unwi  test_dwarf_unwind  [.] funcc
>             |
>             ---funcc
>                |
>                |--0.62%-- funcb
>                |          funca
>                |          main
>                |          __libc_start_main
>                |          _start
>                |
>                 --0.62%-- 0   <-- I applied Jiri's patch in [1] so see this
> 0,
>                                   which indicates a broken call chain.

can't see this case after multiple running your test,
just the 'end-of-the-callchain' zeros

    49.14%  test_dwarf_unwi  [vdso]             [.] __vdso_gettimeofday  
            |
            ---__vdso_gettimeofday
               funcc
               funcb
               funca
               main
               __libc_start_main
               _start
               0

    40.78%  test_dwarf_unwi  [vdso]             [.] 0x0000000000000987   
            |
            ---0x7ffe28ab7987
               __vdso_gettimeofday
               funcc
               funcb
               funca
               main
               __libc_start_main
               _start
               0


what kernel do you have?

jirka
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[BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-18 08:30 +0100
  Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-18 09:20 +0100
    Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction Ingo Molnar <mingo@kernel.org> - 2015-11-18 09:30 +0100
      Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-18 10:00 +0100
        Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction Ingo Molnar <mingo@kernel.org> - 2015-11-19 07:40 +0100
          Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-19 07:50 +0100
            Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction Ingo Molnar <mingo@kernel.org> - 2015-11-19 11:30 +0100
              Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-19 11:50 +0100
                Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-19 12:30 +0100
              Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-19 12:30 +0100
                Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction Ingo Molnar <mingo@kernel.org> - 2015-11-27 09:40 +0100
                Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-30 10:30 +0100
      Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-18 10:10 +0100
  Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction Jiri Olsa <jolsa@redhat.com> - 2015-11-18 09:50 +0100
    Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling  taken at 'callq' instruction "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-18 10:20 +0100

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