perf-probe : error "Rebuild with -g, or install an appropriate debuginfo package"

perf-probe : error "Rebuild with -g, or install an appropriate debuginfo package"

[HOUSSEN Franck]

I compiled myApp.cpp (that contains a function named myFunction) with:
~>mpic++ -O2 -ggdb -fno-omit-frame-pointer -o myApp myApp.cpp

When I try to probe a function from the myApp binary, I get:
~> sudo perf probe --exe ./myApp --add "myFunction:2"
The /home/path/to/myApp file has no debug information.
Rebuild with -g, or install an appropriate debuginfo package.
  Error: Failed to add events.

... -g has been set a t compile time and libelf (and libelf-dev) seems
to be installed:
~> dpkg -l *elf*
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                                  Version
Architecture            Description
+++-=====================================-=======================-===================
un  elf-binutils                          <none>
<none>                  (no description available)
un  libelf                                <none>
<none>                  (no description available)
ii  libelf-dev:amd64                      0.166-2.2
amd64                   libelf1 development libraries and header files
un  libelf0                               <none>
<none>                  (no description available)
ii  libelf1:amd64                         0.166-2.2
amd64                   library to read and write ELF files
ii  libelf1:i386                          0.166-2.2               i386
                   library to read and write ELF files
rc  libelfg0:amd64                        0.8.13-5
amd64                   an ELF object file access library
un  libelfg0-dev                          <none>
<none>                  (no description available)

I googled that without any relevant answer... Could somebody help me
on this ? What's wrong ?

Franck

PS : When I do that
~>sudo perf probe --exe ./myApp --add "myFunction"
Added new event:
  probe_myApp:myFunction (on myFunction in /home/path/to/myApp)

It works !?... I need to place the tracepoint at the second line below
the entry of myFunction => replacing "myFunction" with "myFunction:2"
does not work ! Why ?...

Re: perf-probe : error "Rebuild with -g, or install an appropriate debuginfo package"

[Masami Hiramatsu]

On Wed, 30 Nov 2016 14:49:09 +0100
HOUSSEN Franck <fghoussen@gmail.com> wrote:

> I compiled myApp.cpp (that contains a function named myFunction) with:
> ~>mpic++ -O2 -ggdb -fno-omit-frame-pointer -o myApp myApp.cpp
> 
> When I try to probe a function from the myApp binary, I get:
> ~> sudo perf probe --exe ./myApp --add "myFunction:2"
> The /home/path/to/myApp file has no debug information.
> Rebuild with -g, or install an appropriate debuginfo package.
>   Error: Failed to add events.

Could you run `eu-readelf -S myApp` ?
Could you also try to build your app with '-g' instead of '-ggdb'?
I guess mpic++ might generate some extened debuginfo or just ignored
the option.

> 
> ... -g has been set a t compile time and libelf (and libelf-dev) seems
> to be installed:

No, libelf is not related to this issue.

[...]
> PS : When I do that
> ~>sudo perf probe --exe ./myApp --add "myFunction"
> Added new event:
>   probe_myApp:myFunction (on myFunction in /home/path/to/myApp)
> 
> It works !?... I need to place the tracepoint at the second line below
> the entry of myFunction => replacing "myFunction" with "myFunction:2"
> does not work ! Why ?...

Without line number, perf probe tries to find symbols from symtab in
the binary. DWARF (a.k.a. debuginfo) has much more information, like
line-to-addr, local variable assignment etc.

Thanks,


-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: perf-probe : error "Rebuild with -g, or install an appropriate debuginfo package"

[HOUSSEN Franck]

Installing dwarf was the solution. Now, compiling with either -g or
-ggdb, I can probe the function.

Thanks !

Franck

2016-12-01 6:26 GMT+01:00 Masami Hiramatsu <mhiramat@kernel.org>:
> On Wed, 30 Nov 2016 14:49:09 +0100
> HOUSSEN Franck <fghoussen@gmail.com> wrote:
>
>> I compiled myApp.cpp (that contains a function named myFunction) with:
>> ~>mpic++ -O2 -ggdb -fno-omit-frame-pointer -o myApp myApp.cpp
>>
>> When I try to probe a function from the myApp binary, I get:
>> ~> sudo perf probe --exe ./myApp --add "myFunction:2"
>> The /home/path/to/myApp file has no debug information.
>> Rebuild with -g, or install an appropriate debuginfo package.
>>   Error: Failed to add events.
>
> Could you run `eu-readelf -S myApp` ?
> Could you also try to build your app with '-g' instead of '-ggdb'?
> I guess mpic++ might generate some extened debuginfo or just ignored
> the option.
>
>>
>> ... -g has been set a t compile time and libelf (and libelf-dev) seems
>> to be installed:
>
> No, libelf is not related to this issue.
>
> [...]
>> PS : When I do that
>> ~>sudo perf probe --exe ./myApp --add "myFunction"
>> Added new event:
>>   probe_myApp:myFunction (on myFunction in /home/path/to/myApp)
>>
>> It works !?... I need to place the tracepoint at the second line below
>> the entry of myFunction => replacing "myFunction" with "myFunction:2"
>> does not work ! Why ?...
>
> Without line number, perf probe tries to find symbols from symtab in
> the binary. DWARF (a.k.a. debuginfo) has much more information, like
> line-to-addr, local variable assignment etc.
>
> Thanks,
>
>
> --
> Masami Hiramatsu <mhiramat@kernel.org>



-- 
Bonne journée,

Franck HOUSSEN