Re: [PATCH v1] x86: Fix incorrect scope of setting `shared_per_thread`

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

On Thu, Aug 10, 2023 at 8:38 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Thu, Aug 10, 2023 at 5:31 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > The:
> >
> > ```
> >     if (shared_per_thread > 0 && threads > 0)
> >       shared_per_thread /= threads;
> > ```
> >
> > Code was accidentally moved to inside the else scope.  This doesn't
> > match how it was previously (before af992e7abd).
> >
> > This patch fixes that by putting the division after the `else` block.
>
> Since it is a regression, we should open a bug and backport this
> fix.

Done: See https://sourceware.org/bugzilla/show_bug.cgi?id=30745
FYI: I changed title to include BZ number so doesn't reply in chain.
>
> > ---
> >  sysdeps/x86/dl-cacheinfo.h | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/sysdeps/x86/dl-cacheinfo.h b/sysdeps/x86/dl-cacheinfo.h
> > index 285773039f..88316a7818 100644
> > --- a/sysdeps/x86/dl-cacheinfo.h
> > +++ b/sysdeps/x86/dl-cacheinfo.h
> > @@ -770,11 +770,10 @@ get_common_cache_info (long int *shared_ptr, long int * shared_per_thread_ptr, u
> >              level.  */
> >           threads = ((cpu_features->features[CPUID_INDEX_1].cpuid.ebx >> 16)
> >                      & 0xff);
> > -
> > +        }
> >           /* Get per-thread size of highest level cache.  */
> >           if (shared_per_thread > 0 && threads > 0)
> >             shared_per_thread /= threads;
> > -       }
> >      }
> >
> >    /* Account for non-inclusive L2 and L3 caches.  */
> > --
> > 2.34.1
> >
>
>
> --
> H.J.