From owner-svn-src-head@freebsd.org Sun Aug 2 20:02:06 2020 Return-Path: Delivered-To: svn-src-head@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 ADA1E3A66D8; Sun, 2 Aug 2020 20:02:06 +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 TLSv1.3 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 "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4BKX3f43LSz3dJD; Sun, 2 Aug 2020 20:02:06 +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 6FD138F27; Sun, 2 Aug 2020 20:02:06 +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 072K26c5031423; Sun, 2 Aug 2020 20:02:06 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 072K26lC031422; Sun, 2 Aug 2020 20:02:06 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <202008022002.072K26lC031422@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Sun, 2 Aug 2020 20:02:06 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r363782 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 363782 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: 2.1.33 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: Sun, 02 Aug 2020 20:02:06 -0000 Author: mjg Date: Sun Aug 2 20:02:06 2020 New Revision: 363782 URL: https://svnweb.freebsd.org/changeset/base/363782 Log: vfs: store precomputed namecache hash in the vnode This significantly speeds up path lookup, Cascade Lake doing access(2) on ufs on /usr/obj/usr/src/amd64.amd64/sys/GENERIC/vnode_if.c, ops/s: before: 2535298 after: 2797621 Over +10%. The reversed order of computation here does not seem to matter for hash distribution. Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D25921 Modified: head/sys/kern/vfs_cache.c Modified: head/sys/kern/vfs_cache.c ============================================================================== --- head/sys/kern/vfs_cache.c Sun Aug 2 20:00:43 2020 (r363781) +++ head/sys/kern/vfs_cache.c Sun Aug 2 20:02:06 2020 (r363782) @@ -490,14 +490,22 @@ cache_assert_vnode_locked(struct vnode *vp) cache_assert_vlp_locked(vlp); } +/* + * TODO: With the value stored we can do better than computing the hash based + * on the address and the choice of FNV should also be revisisted. + */ +static void +cache_prehash(struct vnode *vp) +{ + + vp->v_nchash = fnv_32_buf(&vp, sizeof(vp), FNV1_32_INIT); +} + static uint32_t cache_get_hash(char *name, u_char len, struct vnode *dvp) { - uint32_t hash; - hash = fnv_32_buf(name, len, FNV1_32_INIT); - hash = fnv_32_buf(&dvp, sizeof(dvp), hash); - return (hash); + return (fnv_32_buf(name, len, dvp->v_nchash)); } static inline struct rwlock * @@ -2077,6 +2085,7 @@ cache_vnode_init(struct vnode *vp) LIST_INIT(&vp->v_cache_src); TAILQ_INIT(&vp->v_cache_dst); vp->v_cache_dd = NULL; + cache_prehash(vp); } void