[lttng-dev] get function names with lttng-ust-cyg-profile

Liu, Changcheng changcheng.liu at intel.com
Fri Jun 26 22:38:30 EDT 2020


Hi Christophe,
    I've checked lots of examples about func_entry/exit. It seems all
    the address are the linked address. However, my result shows that
    they're the loaded running address.

    Do you have some suggestions to check it further?

B.R.
Changcheng

On 22:22 Fri 26 Jun, Liu, Changcheng wrote:
> On 10:19 Fri 26 Jun, Christophe Bédard wrote:
> >    Hi,
> >    On Tue, 23 Jun 2020 at 21:45, Liu, Changcheng
> >    <[1]changcheng.liu at intel.com> wrote:
> > 
> >      Do you know how to print the call site function_name/offset?
> >      For example:
> >                  11     getchar();
> >                  12
> >                  13     x = add3(x);
> >      Currently, it only shows call_site address instead of function name
> >      with offset.
> >      func_entry: { cpu_id = 2 }, { ip = 0x55CFA4F5C1EE, debug_info = {
> >      bin = "instrument+0x11ee", func = "main+0", src = "instrument.c:7"
> >      }, vpid = 8523 }, { addr = 0x55CFA4F5C1EE, call_site =
> >      0x7F27C4B1E0B3 }
> >      func_entry: { cpu_id = 1 }, { ip = 0x55CFA4F5C1A9, debug_info = {
> >      bin = "instrument+0x11a9", func = "add3+0", src = "instrument.c:3"
> >      }, vpid = 8523 }, { addr = 0x55CFA4F5C1A9, call_site =
> >      0x55CFA4F5C237 }
> >      func_exit: { cpu_id = 1 }, { ip = 0x55CFA4F5C1A9, debug_info = { bin
> >      = "instrument+0x11a9", func = "add3+0", src = "instrument.c:3" },
> >      vpid = 8523 }, { addr = 0x55CFA4F5C1A9, call_site = 0x55CFA4F5C237 }
> >      func_exit: { cpu_id = 1 }, { ip = 0x55CFA4F5C1EE, debug_info = { bin
> >      = "instrument+0x11ee", func = "main+0", src = "instrument.c:7" },
> >      vpid = 8523 }, { addr = 0x55CFA4F5C1EE, call_site = 0x7F27C4B1E0B3 }
> > 
> >     Maybe I'm missing something, but isn't it right here? E.g.
>       I'm also curious about the output here. "main+0" the function name
>       "main" is right, but the offset "+0" isn't right.
>       I've run it for several times, it always shows like the above
>       output.
>       So, two questions here:
>       1. How to show the rigth offset?
>       2. How to show call_site in "func/offset" format?
> > 
> >      debug_info = { bin = "instrument+0x11ee", func = "main+0", src =
> >      "instrument.c:7" }
> > 
> >    Otherwise, I don't think babeltrace can provide any more information.
> >    Christophe
> > 
> > References
> > 
> >    1. mailto:changcheng.liu at intel.com


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