From owner-svn-src-head@freebsd.org Mon Oct 22 06:44:21 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 B9B58FEBA66; Mon, 22 Oct 2018 06:44:21 +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 5E9128B2B5; Mon, 22 Oct 2018 06:44:21 +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 53C8F18BF6; Mon, 22 Oct 2018 06:44:21 +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 w9M6iLBw072323; Mon, 22 Oct 2018 06:44:21 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w9M6iL9C072322; Mon, 22 Oct 2018 06:44:21 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <201810220644.w9M6iL9C072322@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Mon, 22 Oct 2018 06:44:21 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r339579 - 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: 339579 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: 2.1.29 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: Mon, 22 Oct 2018 06:44:21 -0000 Author: mjg Date: Mon Oct 22 06:44:20 2018 New Revision: 339579 URL: https://svnweb.freebsd.org/changeset/base/339579 Log: amd64: finish the tail in memset with an overlapping store Instead of finding the exact size to fit in we can just shift the target by -8 + tail. Doing a blind write to a previously rep stosq'ed area comes with a penalty so do it conditionally. Sample win on EPYC when zeroing a 257 sized buffer (tail = 1) aligned to 16 bytes: before: 44782846 ops/s after: 46118614 ops/s Idea stolen from NetBSD. Sponsored by: The FreeBSD Foundation Modified: head/sys/amd64/amd64/support.S Modified: head/sys/amd64/amd64/support.S ============================================================================== --- head/sys/amd64/amd64/support.S Mon Oct 22 04:12:51 2018 (r339578) +++ head/sys/amd64/amd64/support.S Mon Oct 22 06:44:20 2018 (r339579) @@ -524,9 +524,12 @@ END(memcpy_erms) rep stosq movq %r9,%rax - movq %rdx,%rcx - andb $7,%cl - jne 1004b + andl $7,%edx + jnz 1f + POP_FRAME_POINTER + ret +1: + movq %r10,-8(%rdi,%rdx) .endif POP_FRAME_POINTER ret