From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org,
Noah Goldstein <goldstein.w.n@gmail.com>,
"H . J . Lu" <hjl.tools@gmail.com>,
Bruce Merry <bmerry@sarao.ac.za>
Subject: [PATCH 4/4] x86: Expand the comment on when REP STOSB is used on memset
Date: Tue, 31 Oct 2023 17:09:25 -0300 [thread overview]
Message-ID: <20231031200925.3297456-5-adhemerval.zanella@linaro.org> (raw)
In-Reply-To: <20231031200925.3297456-1-adhemerval.zanella@linaro.org>
---
sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
index 3d9ad49cb9..0821b32997 100644
--- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
+++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
@@ -21,7 +21,9 @@
2. If size is less than VEC, use integer register stores.
3. If size is from VEC_SIZE to 2 * VEC_SIZE, use 2 VEC stores.
4. If size is from 2 * VEC_SIZE to 4 * VEC_SIZE, use 4 VEC stores.
- 5. If size is more to 4 * VEC_SIZE, align to 4 * VEC_SIZE with
+ 5. On machines ERMS feature, if size is greater or equal than
+ __x86_rep_stosb_threshold then REP STOSB will be used.
+ 6. If size is more to 4 * VEC_SIZE, align to 4 * VEC_SIZE with
4 VEC stores and store 4 * VEC at a time until done. */
#include <sysdep.h>
--
2.34.1
next prev parent reply other threads:[~2023-10-31 20:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-31 20:09 [PATCH 0/4] x86: Improve ERMS usage on Zen3+ Adhemerval Zanella
2023-10-31 20:09 ` [PATCH 1/4] elf: Add a way to check if tunable is set (BZ 27069) Adhemerval Zanella
2023-10-31 20:09 ` [PATCH 2/4] x86: Fix Zen3/Zen4 ERMS selection (BZ 30994) Adhemerval Zanella
2023-10-31 20:09 ` [PATCH 3/4] x86: Do not prefer ERMS for memset on Zen3+ Adhemerval Zanella
2023-10-31 20:09 ` Adhemerval Zanella [this message]
2023-11-15 19:05 ` [PATCH 0/4] x86: Improve ERMS usage " sajan.karumanchi
2023-11-16 18:35 ` Adhemerval Zanella Netto
2024-02-05 19:01 ` Sajan Karumanchi
2024-02-06 13:00 ` Adhemerval Zanella Netto
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