From owner-dev-commits-src-branches@freebsd.org Wed Aug 11 00:49:58 2021 Return-Path: Delivered-To: dev-commits-src-branches@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 70734671A46; Wed, 11 Aug 2021 00:49:58 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Gkrnf2mgMz3LLp; Wed, 11 Aug 2021 00:49:58 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4730C25A88; Wed, 11 Aug 2021 00:49:58 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 17B0nwMw086705; Wed, 11 Aug 2021 00:49:58 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 17B0nwIv086704; Wed, 11 Aug 2021 00:49:58 GMT (envelope-from git) Date: Wed, 11 Aug 2021 00:49:58 GMT Message-Id: <202108110049.17B0nwIv086704@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Alexander Motin Subject: git: 70a137b75e14 - stable/12 - Do not expose to scheduler caches of single CPU. MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: mav X-Git-Repository: src X-Git-Refname: refs/heads/stable/12 X-Git-Reftype: branch X-Git-Commit: 70a137b75e149611c101cb57e0322e370f669094 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-branches@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commits to the stable branches of the FreeBSD src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 11 Aug 2021 00:49:58 -0000 The branch stable/12 has been updated by mav: URL: https://cgit.FreeBSD.org/src/commit/?id=70a137b75e149611c101cb57e0322e370f669094 commit 70a137b75e149611c101cb57e0322e370f669094 Author: Alexander Motin AuthorDate: 2021-07-28 20:15:43 +0000 Commit: Alexander Motin CommitDate: 2021-08-11 00:49:48 +0000 Do not expose to scheduler caches of single CPU. Before this change my dual-Xeon(R) Gold 6242R always reported 3 levels or topology (root, package/L3 and core/L2). But with SMT disabled core/L2 matches thread, so additional topology level only causes more traversal work. With this change SMT case is reported same as before, while non-SMT is reported with only 2 much more simple levels. MFC after: 2 weeks (cherry picked from commit 5a49f1914178c5275105f2ab0d23a98118cd585f) --- sys/x86/x86/mp_x86.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/sys/x86/x86/mp_x86.c b/sys/x86/x86/mp_x86.c index 984edb43dd22..73565360007b 100644 --- a/sys/x86/x86/mp_x86.c +++ b/sys/x86/x86/mp_x86.c @@ -817,6 +817,12 @@ x86topo_add_sched_group(struct topo_node *root, struct cpu_group *cg_root) node = topo_next_nonchild_node(root, node); } + /* + * We are not interested in nodes including only one CPU each. + */ + if (nchildren == root->cpu_count) + return; + cg_root->cg_child = smp_topo_alloc(nchildren); cg_root->cg_children = nchildren;