From owner-svn-src-head@freebsd.org Fri Sep 21 12:27:37 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id EBC591098910; Fri, 21 Sep 2018 12:27:36 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 985917C3E6; Fri, 21 Sep 2018 12:27:36 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 840535035; Fri, 21 Sep 2018 12:27:36 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id w8LCRapb025155; Fri, 21 Sep 2018 12:27:36 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w8LCRaqe025154; Fri, 21 Sep 2018 12:27:36 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <201809211227.w8LCRaqe025154@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Fri, 21 Sep 2018 12:27:36 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r338853 - head/sys/amd64/amd64 X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/amd64/amd64 X-SVN-Commit-Revision: 338853 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 Sep 2018 12:27:37 -0000 Author: mjg Date: Fri Sep 21 12:27:36 2018 New Revision: 338853 URL: https://svnweb.freebsd.org/changeset/base/338853 Log: amd64: check for small size in memmove, memcpy and memset If the size is 15 bytes or less avoid spinning up rep just to copy the 8 bytes. In my tests on EPYC and old Intel microarchs without ERMS (like Westmere) it provided a nice win over the current version (e.g. for EPYC memset with 15 bytes of size goes from 59712651 ops/s to 70600095) all while almost not pessimizing the other cases. Data collected during package building shows that < 16 sizes are pretty common. Verified with the glibc test suite. Approved by: re (kib) Modified: head/sys/amd64/amd64/support.S Modified: head/sys/amd64/amd64/support.S ============================================================================== --- head/sys/amd64/amd64/support.S Fri Sep 21 09:27:32 2018 (r338852) +++ head/sys/amd64/amd64/support.S Fri Sep 21 12:27:36 2018 (r338853) @@ -116,6 +116,8 @@ ENTRY(memmove_std) cmpq %rcx,%r8 /* overlapping && src < dst? */ jb 2f + cmpq $15,%rcx + jbe 1f shrq $3,%rcx /* copy by 64-bit words */ rep movsq @@ -124,6 +126,7 @@ ENTRY(memmove_std) jne 1f POP_FRAME_POINTER ret + ALIGN_TEXT 1: rep movsb @@ -191,6 +194,8 @@ ENTRY(memcpy_std) PUSH_FRAME_POINTER movq %rdi,%rax movq %rdx,%rcx + cmpq $15,%rcx + jbe 1f shrq $3,%rcx /* copy by 64-bit words */ rep movsq @@ -199,6 +204,7 @@ ENTRY(memcpy_std) jne 1f POP_FRAME_POINTER ret + ALIGN_TEXT 1: rep movsb @@ -227,6 +233,8 @@ ENTRY(memset_std) movzbq %sil,%r8 movabs $0x0101010101010101,%rax imulq %r8,%rax + cmpq $15,%rcx + jbe 1f shrq $3,%rcx rep stosq @@ -236,6 +244,7 @@ ENTRY(memset_std) movq %r9,%rax POP_FRAME_POINTER ret + ALIGN_TEXT 1: rep stosb