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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 065F3EB64DA for ; Wed, 28 Jun 2023 10:12:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231325AbjF1KMI (ORCPT ); Wed, 28 Jun 2023 06:12:08 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:1522 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232304AbjF1KIM (ORCPT ); Wed, 28 Jun 2023 06:08:12 -0400 Received: from pps.filterd (m0353723.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 35SA3Yl4004195; Wed, 28 Jun 2023 10:08:01 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : mime-version; s=pp1; bh=GYATAPJgEf5n8C1QFvq6gF7ANrUUiLJuPhc2JRfH2cw=; b=Yr+6UWCaagmvD3OwwiM7fX/JrcvQ9L1W05eLu23CMQe0QPj2u/quVubkR/tCKYZWatD8 a3Wvi70xGDetry/GG6pcaWllIhCWWykvJa5oTaiuo95AAwPvSBq1N6FaQpWZd7PC7DYQ YSs5VFtc4P6Sxeg02rbm7Uxd28hR00KKHzkwSA5wGcQwZVcUFdKtdQHp/v0OV4wJ89FW MTFYLz8WvZTzR58n7+K6qSlIhtnaQde2LPbaHsqPS2m5yl9dn39dZiY9gR7Djff2RIP9 cRQqb+AjtlmjaYTLl23b6p3yhHCD6D4KKBGjXk/tLLiUDfkCGTgw4R7N0DyAfWC9R+Dl Rg== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3rgjs5r41s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Jun 2023 10:07:58 +0000 Received: from m0353723.ppops.net (m0353723.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 35SA3m7o005189; Wed, 28 Jun 2023 10:07:31 GMT Received: from ppma03fra.de.ibm.com (6b.4a.5195.ip4.static.sl-reverse.com [149.81.74.107]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3rgjs5r37b-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Jun 2023 10:07:31 +0000 Received: from pps.filterd (ppma03fra.de.ibm.com [127.0.0.1]) by ppma03fra.de.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 35S1J41S010907; Wed, 28 Jun 2023 10:06:02 GMT Received: from smtprelay05.fra02v.mail.ibm.com ([9.218.2.225]) by ppma03fra.de.ibm.com (PPS) with ESMTPS id 3rdr451vwj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Jun 2023 10:06:02 +0000 Received: from smtpav07.fra02v.mail.ibm.com (smtpav07.fra02v.mail.ibm.com [10.20.54.106]) by smtprelay05.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 35SA60OV57999714 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 28 Jun 2023 10:06:00 GMT Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 20EDA20065; Wed, 28 Jun 2023 10:06:00 +0000 (GMT) Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4A3C820043; Wed, 28 Jun 2023 10:05:59 +0000 (GMT) Received: from localhost.localdomain (unknown [9.171.41.43]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 28 Jun 2023 10:05:59 +0000 (GMT) From: Laurent Dufour To: linuxppc-dev@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, tglx@linutronix.de, dave.hansen@linux.intel.com, mingo@redhat.com, bp@alien8.de Subject: [PATCH v2 0/9] Introduce SMT level and add PowerPC support Date: Wed, 28 Jun 2023 12:05:49 +0200 Message-ID: <20230628100558.43482-1-ldufour@linux.ibm.com> X-Mailer: git-send-email 2.41.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: Mh8j18TQO3BlWq7spvNv71k46Geassb1 X-Proofpoint-ORIG-GUID: tCy5u0t9HvF1n92iDQZFkNza9ljJV4Mw Content-Transfer-Encoding: 8bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-06-28_06,2023-06-27_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 priorityscore=1501 mlxscore=0 impostorscore=0 adultscore=0 spamscore=0 lowpriorityscore=0 malwarescore=0 phishscore=0 mlxlogscore=999 suspectscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2306280088 Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org I'm taking over the series Michael sent previously [1] which is smartly reviewing the initial series I sent [2]. This series is addressing the comments sent by Thomas and me on the Michael's one. Here is a short introduction to the issue this series is addressing: When a new CPU is added, the kernel is activating all its threads. This leads to weird, but functional, result when adding CPU on a SMT 4 system for instance. Here the newly added CPU 1 has 8 threads while the other one has 4 threads active (system has been booted with the 'smt-enabled=4' kernel option): ltcden3-lp12:~ # ppc64_cpu --info Core 0: 0* 1* 2* 3* 4 5 6 7 Core 1: 8* 9* 10* 11* 12* 13* 14* 15* This mixed SMT level may confused end users and/or some applications. There is no SMT level recorded in the kernel (common code), neither in user space, as far as I know. Such a level is helpful when adding new CPU or when optimizing the energy efficiency (when reactivating CPUs). When SMP and HOTPLUG_SMT are defined, this series is adding a new SMT level (cpu_smt_num_threads) and few callbacks allowing the architecture code to fine control this value, setting a max and a "at boot" level, and controling whether a thread should be onlined or not. v2: As Thomas suggested, Reword some commit's description Remove topology_smt_supported() Remove topology_smt_threads_supported() Introduce CONFIG_SMT_NUM_THREADS_DYNAMIC Remove switch() in __store_smt_control() Update kernel-parameters.txt [1] https://lore.kernel.org/linuxppc-dev/20230524155630.794584-1-mpe@ellerman.id.au/ [2] https://lore.kernel.org/linuxppc-dev/20230331153905.31698-1-ldufour@linux.ibm.com/ Laurent Dufour (1): cpu/SMT: Remove topology_smt_supported() Michael Ellerman (8): cpu/SMT: Move SMT prototypes into cpu_smt.h cpu/SMT: Move smt/control simple exit cases earlier cpu/SMT: Store the current/max number of threads cpu/SMT: Create topology_smt_thread_allowed() cpu/SMT: Allow enabling partial SMT states via sysfs powerpc/pseries: Initialise CPU hotplug callbacks earlier powerpc: Add HOTPLUG_SMT support powerpc/pseries: Honour current SMT state when DLPAR onlining CPUs .../ABI/testing/sysfs-devices-system-cpu | 1 + .../admin-guide/kernel-parameters.txt | 4 +- arch/Kconfig | 3 + arch/powerpc/Kconfig | 2 + arch/powerpc/include/asm/topology.h | 15 +++ arch/powerpc/kernel/smp.c | 8 +- arch/powerpc/platforms/pseries/hotplug-cpu.c | 30 +++-- arch/powerpc/platforms/pseries/pseries.h | 2 + arch/powerpc/platforms/pseries/setup.c | 2 + arch/x86/include/asm/topology.h | 4 +- arch/x86/kernel/cpu/bugs.c | 3 +- arch/x86/kernel/smpboot.c | 8 -- include/linux/cpu.h | 25 +--- include/linux/cpu_smt.h | 33 +++++ kernel/cpu.c | 116 ++++++++++++++---- 15 files changed, 185 insertions(+), 71 deletions(-) create mode 100644 include/linux/cpu_smt.h -- 2.41.0