From 272708884cb750f12f5c74a00e6620c19dc6d567 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Thu, 8 Feb 2024 10:08:39 -0300 Subject: [PATCH] x86: Do not prefer ERMS for memset on Zen3+ Content-type: text/plain; charset=UTF-8 For AMD Zen3+ architecture, the performance of the vectorized loop is slightly better than ERMS. Checked on x86_64-linux-gnu on Zen3. Reviewed-by: H.J. Lu --- sysdeps/x86/dl-cacheinfo.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/sysdeps/x86/dl-cacheinfo.h b/sysdeps/x86/dl-cacheinfo.h index f34d12846c..5a98f70364 100644 --- a/sysdeps/x86/dl-cacheinfo.h +++ b/sysdeps/x86/dl-cacheinfo.h @@ -1021,6 +1021,11 @@ dl_init_cacheinfo (struct cpu_features *cpu_features) minimum value is fixed. */ rep_stosb_threshold = TUNABLE_GET (x86_rep_stosb_threshold, long int, NULL); + if (cpu_features->basic.kind == arch_kind_amd + && !TUNABLE_IS_INITIALIZED (x86_rep_stosb_threshold)) + /* For AMD Zen3+ architecture, the performance of the vectorized loop is + slightly better than ERMS. */ + rep_stosb_threshold = SIZE_MAX; TUNABLE_SET_WITH_BOUNDS (x86_data_cache_size, data, 0, SIZE_MAX); TUNABLE_SET_WITH_BOUNDS (x86_shared_cache_size, shared, 0, SIZE_MAX); -- 2.39.3