From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 056DEC28CBC for ; Sun, 3 May 2020 18:55:04 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CCD3D2068E for ; Sun, 3 May 2020 18:55:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CCD3D2068E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bugs.launchpad.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34442 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jVJlX-0003Iy-2m for qemu-devel@archiver.kernel.org; Sun, 03 May 2020 14:55:03 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60440) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jVJhJ-0006pN-RF for qemu-devel@nongnu.org; Sun, 03 May 2020 14:50:41 -0400 Received: from indium.canonical.com ([91.189.90.7]:55204) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jVJhI-0005g4-Le for qemu-devel@nongnu.org; Sun, 03 May 2020 14:50:41 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.86_2 #2 (Debian)) id 1jVJhG-0003IW-Ol for ; Sun, 03 May 2020 18:50:38 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id B971D2E810A for ; Sun, 3 May 2020 18:50:38 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Sun, 03 May 2020 18:38:37 -0000 From: Heiko Sieger <1856335@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=New; importance=Undecided; assignee=None; X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: babumoger djdatte h-sieger X-Launchpad-Bug-Reporter: Damir (djdatte) X-Launchpad-Bug-Modifier: Heiko Sieger (h-sieger) References: <157625616239.22064.10423897892496347105.malonedeb@gac.canonical.com> Message-Id: <158853111753.13722.1662239803306917069.malone@gac.canonical.com> Subject: [Bug 1856335] Re: Cache Layout wrong on many Zen Arch CPUs X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="fbdff7602bd10fb883bf7e2ddcc7fd5a16f60398"; Instance="production-secrets-lazr.conf" X-Launchpad-Hash: f0d831165253011348473468f6a34d697532a985 Received-SPF: none client-ip=91.189.90.7; envelope-from=bounces@canonical.com; helo=indium.canonical.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/03 14:10:50 X-ACL-Warn: Detected OS = Linux 3.11 and newer X-Spam_score_int: -65 X-Spam_score: -6.6 X-Spam_bar: ------ X-Spam_report: (-6.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1856335 <1856335@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Here the vm.log with the qemu command line (shortened): 2020-05-03 18:23:38.674+0000: starting up libvirt version: 5.10.0, qemu version: 5.0.50v5.0.0-154-g2ef486e76d-dirty, kernel: 5.4.36-1-MANJARO -machine pc-q35-4.2,accel=3Dkvm,usb=3Doff,vmport=3Doff,dump-guest-core=3Dof= f,kernel_irqchip=3Don,pflash0=3Dlibvirt-pflash0-format,pflash1=3Dlibvirt-pf= lash1-format \ -cpu host,invtsc=3Don,hypervisor=3Don,topoext=3Don,hv-time,hv-relaxed,hv-va= pic,hv-spinlocks=3D0x1fff,hv-vpindex,hv-synic,hv-stimer,hv-vendor-id=3DAuth= enticAMD,hv-frequencies,hv-crash,kvm=3Doff,host-cache-info=3Don,l3-cache=3D= off \ -m 49152 \ -mem-prealloc \ -mem-path /dev/hugepages/libvirt/qemu/1-win10 \ -overcommit mem-lock=3Doff \ -smp 24,sockets=3D1,cores=3D12,threads=3D2 \ -display none \ -no-user-config \ -nodefaults \ -chardev socket,id=3Dcharmonitor,fd=3D34,server,nowait \ -mon chardev=3Dcharmonitor,id=3Dmonitor,mode=3Dcontrol \ -rtc base=3Dlocaltime,driftfix=3Dslew \ -global kvm-pit.lost_tick_policy=3Ddelay \ -no-hpet \ -no-shutdown \ -global ICH9-LPC.disable_s3=3D1 \ -global ICH9-LPC.disable_s4=3D1 \ -boot menu=3Doff,strict=3Don \ -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1856335 Title: Cache Layout wrong on many Zen Arch CPUs Status in QEMU: New Bug description: AMD CPUs have L3 cache per 2, 3 or 4 cores. Currently, TOPOEXT seems to always map Cache ass if it was an 4-Core per CCX CPU, which is incorrect, and costs upwards 30% performance (more realistically 10%) in L3 Cache Layout aware applications. Example on a 4-CCX CPU (1950X /w 8 Cores and no SMT): =C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0EPYC-IBPB =C2=A0=C2=A0=C2=A0=C2=A0AMD =C2=A0=C2=A0=C2=A0=C2=A0 In windows, coreinfo reports correctly: ****---- Unified Cache 1, Level 3, 8 MB, Assoc 16, LineSize 64 ----**** Unified Cache 6, Level 3, 8 MB, Assoc 16, LineSize 64 On a 3-CCX CPU (3960X /w 6 cores and no SMT): =C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0EPYC-IBPB =C2=A0=C2=A0=C2=A0=C2=A0AMD =C2=A0=C2=A0=C2=A0=C2=A0 in windows, coreinfo reports incorrectly: ****-- Unified Cache 1, Level 3, 8 MB, Assoc 16, LineSize 64 ----** Unified Cache 6, Level 3, 8 MB, Assoc 16, LineSize 64 Validated against 3.0, 3.1, 4.1 and 4.2 versions of qemu-kvm. With newer Qemu there is a fix (that does behave correctly) in using the = dies parameter: =C2=A0 The problem is that the dies are exposed differently than how AMD does it natively, they are exposed to Windows as sockets, which means, that if you are nto a business user, you can't ever have a machine with more than two CCX (6 cores) as consumer versions of Windows only supports two sockets. (Should this be reported as a separate bug?) To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1856335/+subscriptions