Re: ____wcstold_l_internal Question

[Noah Goldstein <goldstein.w.n@gmail.com>]

On Thu, Dec 1, 2022 at 10:09 PM Florian Weimer via Libc-help
<libc-help@sourceware.org> wrote:
>
> * Samir Droubi via Libc-help:
>
> > I was profiling a project that I have been working on and the function
> > above shows up amongst other internal functions. I was wondering if
> > you could shed a light on what could possibly be happening to cause
> > calls to this function to be so frequent. Here is the profiling
> > result:
> >
> >   13.72%  mitscriptbc  libc.so.6             [.] ____wcstold_l_internal
> >    5.45%  mitscriptbc  libc.so.6             [.] ____wcstof_l_internal
> >    2.46%  mitscriptbc  libc.so.6             [.] round_and_return
> >    2.28%  mitscriptbc  libc.so.6             [.] ____wcstod_l_internal
> >
> > The libc version being used is 2.35.
I've noticed on ubuntu 22.04 (2.35 as well) `__wcstold_l` is showing up
in perf profiles incorrectly. It's usually malloc / memcpy / whatever other
functions are usually hot if you look at the asm.

Not sure where the bug is but don't think `__wcstold` is whats taking up
all those cycles.
>
> The external name is wcstold or wcstold_l.  If your application isn't
> calling that, the profiling data is wrong.  You might find out by
> setting a breakpoint or probe on the function.
>
> Thanks,
> Florian
>