Re: [PATCH V5 3/9] perf tools: workaround objdump difficulties withkcore

[Jiri Olsa]

On Wed, Oct 09, 2013 at 10:33:25AM +0300, Adrian Hunter wrote:
> On 08/10/13 17:02, Jiri Olsa wrote:
> > On Tue, Oct 08, 2013 at 11:45:50AM +0300, Adrian Hunter wrote:
> >> objdump fails to annotate module symbols when looking
> >> at kcore.  Workaround this by extracting object code
> >> from kcore and putting it in a temporary file for
> >> objdump to use instead.  The temporary file is created
> >> to look like kcore but contains only the function
> >> being disassembled.
> > 
> > Excited to ses this one, but looks like I'm hitting some
> > issue.  All annotation starts for me like this:
> > 
> >                                                                                                        â
> >        â              Disassembly of section load0:                                                            â
> >        â                                                                                                       â
> >        â              ffffffff815eee80 <load0>:                                                                â
> >   9.33 âffffffff815eee80:   data32 data32 data32 xchg %ax,%ax                                                  
> > 
> > 
> > which does not seem right
> 
> Can you tell me the commits of the kernel and perf tools you
> were using, plus the commands and what symbol it was?

kernel: 3.9.10-100.fc17.x86_64
perf:   latest acme's perf/core (06de626 perf evlist: Fix perf_evlist__mmap_read event overflow )
        plus your V5 patches

commands:
  sudo ./perf record -e cycles:k -a 
  sudo ./perf report

---
Samples: 2K of event 'cycles:k', Event count (approx.): 445188286                                               
 14.73%          swapper  [kernel.kallsyms]   [k] intel_idle                                                   â
  3.19%                X  [kernel.kallsyms]   [k] smp_call_function_many                                       â
  1.58%                X  [kernel.kallsyms]   [k] i915_gem_write_fence__ipi                                    â
  1.58%          swapper  [kernel.kallsyms]   [k] iwl_trans_pcie_read32                                        â


annotation of 1st 4 symbols:

---
intel_idle  /proc/kcore                                                                                         
       â                                                                                                       â
       â                                                                                                       â
       â                                                                                                       â
       â     Disassembly of section load0:                                                                     â
       â                                                                                                       â
       â     ffffffff8135f490 <load0>:                                                                         â
  1.18 â       data32 data32 data32 xchg %ax,%ax                                                               â


---
smp_call_function_many  /proc/kcore                                                                             
       â                                                                                                       â
       â                                                                                                       â
       â                                                                                                       â
       â     Disassembly of section load0:                                                                     â
       â                                                                                                       â
       â     ffffffff810bc270 <load0>:                                                                         â
       â       data32 data32 data32 xchg %ax,%ax                                                               â

---
i915_gem_write_fence__ipi  /proc/kcore                                                                          
       â
       â
       â
       â    Disassembly of section load0:
       â
       â    ffffffffa0086630 <load0>:
       â      data32 data32 data32 xchg %ax,%ax

---
iwl_trans_pcie_read32  /proc/kcore                                                                              
       â
       â
       â
       â    Disassembly of section load0:
       â
       â    ffffffffa0414a50 <load0>:
       â      data32 data32 data32 xchg %ax,%ax


the rest of the instruction decode differs.. just the first
line is same for all

addresses seem ok:

[jolsa@krava perf]$ egrep 'ffffffff8135f490|ffffffff810bc270|ffffffffa0086630|ffffffffa0414a50' /proc/kallsyms 
ffffffff810bc270 T smp_call_function_many
ffffffff8135f490 t intel_idle
ffffffffa0414a50 t iwl_trans_pcie_read32        [iwlwifi]
ffffffffa0086630 t i915_gem_write_fence__ipi    [i915]

so.. the name of the section, name of the <function> plus the first
instruction decode seem wrong.. I can see that in every symbol I
annotate in the report and in annotate command as well.

jirka
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