From owner-svn-src-all@freebsd.org Sun Jul 7 18:42:26 2019 Return-Path: Delivered-To: svn-src-all@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 C423515EB2E2; Sun, 7 Jul 2019 18:42:26 +0000 (UTC) (envelope-from mav@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) server-signature RSA-PSS (4096 bits) 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 6A3A46D2E9; Sun, 7 Jul 2019 18:42:26 +0000 (UTC) (envelope-from mav@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 44F655272; Sun, 7 Jul 2019 18:42:26 +0000 (UTC) (envelope-from mav@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x67IgQxl074954; Sun, 7 Jul 2019 18:42:26 GMT (envelope-from mav@FreeBSD.org) Received: (from mav@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x67IgQiU074953; Sun, 7 Jul 2019 18:42:26 GMT (envelope-from mav@FreeBSD.org) Message-Id: <201907071842.x67IgQiU074953@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mav set sender to mav@FreeBSD.org using -f From: Alexander Motin Date: Sun, 7 Jul 2019 18:42:26 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r349822 - stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs X-SVN-Group: stable-12 X-SVN-Commit-Author: mav X-SVN-Commit-Paths: stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs X-SVN-Commit-Revision: 349822 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 6A3A46D2E9 X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-2.94 / 15.00]; local_wl_from(0.00)[FreeBSD.org]; NEURAL_HAM_MEDIUM(-1.00)[-0.999,0]; NEURAL_HAM_SHORT(-0.94)[-0.944,0]; ASN(0.00)[asn:12874, ipnet:2000::/3, country:IT]; NEURAL_HAM_LONG(-1.00)[-1.000,0] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 07 Jul 2019 18:42:27 -0000 Author: mav Date: Sun Jul 7 18:42:25 2019 New Revision: 349822 URL: https://svnweb.freebsd.org/changeset/base/349822 Log: MFC r349040: Minimize aggsum_compare(&arc_size, arc_c) calls. For busy ARC situation when arc_size close to arc_c is desired. But then it is quite likely that aggsum_compare(&arc_size, arc_c) will need to flush per-CPU buckets to find exact comparison result. Doing that often in a hot path penalizes whole idea of aggsum usage there, since it replaces few simple atomic additions with dozens of lock acquisitions. Replacing aggsum_compare() with aggsum_upper_bound() in code increasing arc_p when ARC is growing (arc_size < arc_c) according to PMC profiles allows to save ~5% of CPU time in aggsum code during sequential write to 12 ZVOLs with 16KB block size on large dual-socket system. I suppose there some minor arc_p behavior change due to lower precision of the new code, but I don't think it is a big deal, since it should affect only very small window in time (aggsum buckets are flushed every second) and in ARC size (buckets are limited to 10 average ARC blocks per CPU). Modified: stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c ============================================================================== --- stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Sun Jul 7 18:40:35 2019 (r349821) +++ stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Sun Jul 7 18:42:25 2019 (r349822) @@ -5269,7 +5269,7 @@ arc_get_data_impl(arc_buf_hdr_t *hdr, uint64_t size, v * If we are growing the cache, and we are adding anonymous * data, and we have outgrown arc_p, update arc_p */ - if (aggsum_compare(&arc_size, arc_c) < 0 && + if (aggsum_upper_bound(&arc_size) < arc_c && hdr->b_l1hdr.b_state == arc_anon && (refcount_count(&arc_anon->arcs_size) + refcount_count(&arc_mru->arcs_size) > arc_p))