From: Noah Goldstein <goldstein.w.n@gmail.com>
Date: Tue, 18 Jul 2023 04:14:33 +0000 (-0500)
Subject: x86: Fix slight bug in `shared_per_thread` cache size calculation.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=31b06441f9f82be270b3fe486eaa76bd1d866477;p=thirdparty%2Fglibc.git

x86: Fix slight bug in `shared_per_thread` cache size calculation.

After:
```
    commit af992e7abdc9049714da76cae1e5e18bc4838fb8
    Author: Noah Goldstein <goldstein.w.n@gmail.com>
    Date:   Wed Jun 7 13:18:01 2023 -0500

        x86: Increase `non_temporal_threshold` to roughly `sizeof_L3 / 4`
```

Split `shared` (cumulative cache size) from `shared_per_thread` (cache
size per socket), the `shared_per_thread` *can* be slightly off from
the previous calculation.

Previously we added `core` even if `threads_l2` was invalid, and only
used `threads_l2` to divide `core` if it was present. The changed
version only included `core` if `threads_l2` was valid.

This change restores the old behavior if `threads_l2` is invalid by
adding the entire value of `core`.
Reviewed-by: DJ Delorie <dj@redhat.com>

(cherry picked from commit 47f747217811db35854ea06741be3685e8bbd44d)
---

diff --git a/sysdeps/x86/dl-cacheinfo.h b/sysdeps/x86/dl-cacheinfo.h
index 71326a604dc..c885b23f7a3 100644
--- a/sysdeps/x86/dl-cacheinfo.h
+++ b/sysdeps/x86/dl-cacheinfo.h
@@ -685,8 +685,8 @@ get_common_cache_info (long int *shared_ptr, long int * shared_per_thread_ptr, u
   /* Account for non-inclusive L2 and L3 caches.  */
   if (!inclusive_cache)
     {
-      if (threads_l2 > 0)
-	shared_per_thread += core / threads_l2;
+      long int core_per_thread = threads_l2 > 0 ? (core / threads_l2) : core;
+      shared_per_thread += core_per_thread;
       shared += core;
     }