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Diffstat (limited to 'sysdeps/x86/dl-cacheinfo.h')
-rw-r--r--sysdeps/x86/dl-cacheinfo.h8
1 files changed, 7 insertions, 1 deletions
diff --git a/sysdeps/x86/dl-cacheinfo.h b/sysdeps/x86/dl-cacheinfo.h
index 560bf260e8..8f85f70858 100644
--- a/sysdeps/x86/dl-cacheinfo.h
+++ b/sysdeps/x86/dl-cacheinfo.h
@@ -931,8 +931,14 @@ dl_init_cacheinfo (struct cpu_features *cpu_features)
 
   TUNABLE_SET_WITH_BOUNDS (x86_data_cache_size, data, 0, SIZE_MAX);
   TUNABLE_SET_WITH_BOUNDS (x86_shared_cache_size, shared, 0, SIZE_MAX);
+  /* SIZE_MAX >> 4 because memmove-vec-unaligned-erms right-shifts the value of
+     'x86_non_temporal_threshold' by `LOG_4X_MEMCPY_THRESH` (4) and it is best
+     if that operation cannot overflow. Minimum of 0x4040 (16448) because the
+     L(large_memset_4x) loops need 64-byte to cache align and enough space for
+     at least 1 iteration of 4x PAGE_SIZE unrolled loop.  Both values are
+     reflected in the manual.  */
   TUNABLE_SET_WITH_BOUNDS (x86_non_temporal_threshold, non_temporal_threshold,
-			   0, SIZE_MAX);
+			   0x4040, SIZE_MAX >> 4);
   TUNABLE_SET_WITH_BOUNDS (x86_rep_movsb_threshold, rep_movsb_threshold,
 			   minimum_rep_movsb_threshold, SIZE_MAX);
   TUNABLE_SET_WITH_BOUNDS (x86_rep_stosb_threshold, rep_stosb_threshold, 1,