From owner-freebsd-bugs@freebsd.org Wed Mar 6 10:09:16 2019 Return-Path: Delivered-To: freebsd-bugs@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 E4EEF150ABCA for ; Wed, 6 Mar 2019 10:09:15 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 79F2185D0C for ; Wed, 6 Mar 2019 10:09:15 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id 3542B150ABC9; Wed, 6 Mar 2019 10:09:15 +0000 (UTC) Delivered-To: bugs@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 106EF150ABC8 for ; Wed, 6 Mar 2019 10:09:15 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::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.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 996C185D08 for ; Wed, 6 Mar 2019 10:09:14 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id E14C05C02 for ; Wed, 6 Mar 2019 10:09:13 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id x26A9DPN052950 for ; Wed, 6 Mar 2019 10:09:13 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id x26A9D6i052949 for bugs@FreeBSD.org; Wed, 6 Mar 2019 10:09:13 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 236233] Python multiprocessing is 4x slower with 11.2 compared to 11.0 kernel Date: Wed, 06 Mar 2019 10:09:14 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 11.2-RELEASE X-Bugzilla-Keywords: regression X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: arichardson@FreeBSD.org X-Bugzilla-Status: Open X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_status short_desc Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Mar 2019 10:09:16 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D236233 Alex Richardson changed: What |Removed |Added ---------------------------------------------------------------------------- Status|New |Open Summary|Python multiprocessing is |Python multiprocessing is |20x slower with 11.2 |4x slower with 11.2 |compared to 11.0 kernel |compared to 11.0 kernel --- Comment #2 from Alex Richardson --- I finished bisecting and the following commit is causing the slowdown: 6dd025b40ee6870bea6ba670f30dcf684edc3f6c is the first bad commit commit 6dd025b40ee6870bea6ba670f30dcf684edc3f6c Author: kib Date: Sat Feb 17 18:00:01 2018 +0000 MFC r328083,328096,328116,328119,328120,328128,328135,328153,328157, 328166,328177,328199,328202,328205,328468,328470,328624,328625,328627, 328628,329214,329297,329365: Meltdown mitigation by PTI, PCID optimization of PTI, and kernel use of IBRS for some mitigations of Spectre. Tested by: emaste, Arshan Khanifar Discussed with: jkim Sponsored by: The FreeBSD Foundation I also checked that ibrs was off so this seems to be caused by something el= se in this massive commit. $ sysctl hw.ibrs_active hw.ibrs_active: 0 $ sysctl hw.ibrs_disable hw.ibrs_disable: 1 The time it took to run the test command was very consistent: Working commit: r313908+bc19f9718e7(stable/11) -> 26.8seconds Known bad commit: a190b45c053(stable/11) -> 121.12s 1st step: fd638422ccfbbe7a11e751ed5a7a237f2dc8d004 -> 133.14s 2nd step: 4ebdf0a463e767672045047ec82c75bf545e9a7c -> 25.48s 3rd step: 483c180d2dece828b1800896e642bcb806075c1f -> 133.49s 4th step: e38b1b844d045fb5dcf4db6f2795f7797022ca17 -> 24.97s 5th step (141 to go): 97ca83c5b618a025fdac8e62db23afa7abd198c8 -> 25.27s 6th step (70 to go): cdf8c6144ce326759989ebcbc0d9b5195bd4f811 -> 133.64s 7th step (35 to go): e2f594b309b8fd60b6ab39982b9ba0f6da798f38 -> 134.01s 8th step (17 to go): 195e563d5c9edb667d92e2480a07080ae6ba40ac -> 24.80s 9th step (8 to go): 61669078139eef2cb35756674ab6e925e97ab5ba -> 134.34s 10th step (4 to go): af7d202e1dcdeda020ee1fdb96e2b1eb4dbbad39 -> 133.04s 11th step (1 to go): 6dd025b40ee6870bea6ba670f30dcf684edc3f6c -> 133.92s 12th step (0 to go): ebe022b0c9f14dc22edbe0308795d42c9f93fd39 -> 24.86s --=20 You are receiving this mail because: You are the assignee for the bug.=