From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1039) id 3C3B83858037; Tue, 13 Feb 2024 16:54:25 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 3C3B83858037 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1707843265; bh=jJQu7LitRJtppa2rnjR8/awTs+ns5TqFe1wMOcnL3bk=; h=From:To:Subject:Date:From; b=bbSqtV10N68r+qlyCoB8yuavtr21LOh2YlnE3NulX1m3UCz1Y/tZ4ER7gMqGngS2W FUmA6vbYLIAFTRFqDAt7ErTOmh9c884xFlENcJPmvLMzovvZKXmZrpaGipiBWcvv1W KmNnuQrpYE+LXD+4ngNavFfTgQ9FsdN6F/cfIdjY= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: H.J. Lu To: glibc-cvs@sourceware.org Subject: [glibc] x86: Expand the comment on when REP STOSB is used on memset X-Act-Checkin: glibc X-Git-Author: Adhemerval Zanella X-Git-Refname: refs/heads/master X-Git-Oldrev: 272708884cb750f12f5c74a00e6620c19dc6d567 X-Git-Newrev: 491e55beab7457ed310a4a47496f4a333c5d1032 Message-Id: <20240213165425.3C3B83858037@sourceware.org> Date: Tue, 13 Feb 2024 16:54:25 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=491e55beab7457ed310a4a47496f4a333c5d1032 commit 491e55beab7457ed310a4a47496f4a333c5d1032 Author: Adhemerval Zanella Date: Thu Feb 8 10:08:40 2024 -0300 x86: Expand the comment on when REP STOSB is used on memset Reviewed-by: H.J. Lu Diff: --- 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 9984c3ca0f..97839a2248 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