From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4F20B13FD83 for ; Thu, 26 Dec 2024 09:24:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735205098; cv=none; b=PuE5G1oHMRxPjLBzzmfBe3XcfimP5NH+XzzB42dN5tM54ORs0rBMK/UUkAbezSVaypCYmYG/b67xhRnYMjONy2nYGAI60/6JYJt7xJeuuxlE8L/DPIGQIa27uydmzRi/2cT+DC9P3LQdQ0+ass9+PBQ1y1NtxYNtdKfBCXODZeg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735205098; c=relaxed/simple; bh=JY48GDxjjxN1amAgiUB2lTZN4euTRJXggU+KeXP2D6E=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=gxyHdsaSXftsgyZlpbs6qZ8dqDoW/dTrxBwk/FEx1OGCaI7f9HdiQEy7gMF2B2MN5uXXpH4PFBHqQHdWuPCubB4OZY78V+MqzP7obUi4hGMN9FU9ASvkBDOtvHenY8FR08JFxngGg5KLJWbzUavxSd5frzRCflDLzTdfiSPmbM0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=heiEhqAJ; arc=none smtp.client-ip=148.163.156.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="heiEhqAJ" Received: from pps.filterd (m0356517.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4BQ3sI6M008911; Thu, 26 Dec 2024 09:23:42 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=HG/2rL Z96lKXoOhm/FE0fLTX6r570qhTekaN5ef5EsQ=; b=heiEhqAJF6PB/bM1AYVNla qdsA/8GwzTX2cw241Vmn0g/Xkd3Nz33Q/Nx4b+0CkGOnut3swCeK9PSuTgJgb86M czX4dF8uH+WiD3EHrQDjBDgBZHbhojwW0RxOLfzZCbU5MEMKiiaQReAP95Sm4LV4 K4wBjszYgltx/Ow1KF0vDz6GihRSof57or0r+3RWZKlltzjIDdsXqXYsox/gyte1 hkY6+4IrlQfv8x4bHHWt8Niapik1p1Kjbbl4wG8kfm0z20eVCQEusd6ZYMDbbgpR 7kmN0KiFA+4ASmHINbQx6gNYpHJ5eEcMw7XGjGwQzyZmUdKUnWwKpKxdVNm2nh1A == Received: from ppma21.wdc07v.mail.ibm.com (5b.69.3da9.ip4.static.sl-reverse.com [169.61.105.91]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 43rymh12t5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 26 Dec 2024 09:23:42 +0000 (GMT) Received: from pps.filterd (ppma21.wdc07v.mail.ibm.com [127.0.0.1]) by ppma21.wdc07v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 4BQ5VhGj010570; Thu, 26 Dec 2024 09:23:41 GMT Received: from smtprelay05.fra02v.mail.ibm.com ([9.218.2.225]) by ppma21.wdc07v.mail.ibm.com (PPS) with ESMTPS id 43p90n9eng-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 26 Dec 2024 09:23:40 +0000 Received: from smtpav05.fra02v.mail.ibm.com (smtpav05.fra02v.mail.ibm.com [10.20.54.104]) by smtprelay05.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 4BQ9NcB856689004 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 26 Dec 2024 09:23:39 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DE0A52004B; Thu, 26 Dec 2024 09:23:38 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C920320040; Thu, 26 Dec 2024 09:23:33 +0000 (GMT) Received: from [9.124.219.96] (unknown [9.124.219.96]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 26 Dec 2024 09:23:33 +0000 (GMT) Message-ID: Date: Thu, 26 Dec 2024 14:53:32 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 0/4] Support SMT control on arm64 To: Yicong Yang Cc: linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, morten.rasmussen@arm.com, msuchanek@suse.de, gregkh@linuxfoundation.org, rafael@kernel.org, jonathan.cameron@huawei.com, prime.zeng@hisilicon.com, linuxarm@huawei.com, yangyicong@hisilicon.com, xuwei5@huawei.com, guohanjun@huawei.com, catalin.marinas@arm.com, will@kernel.org, sudeep.holla@arm.com, tglx@linutronix.de, peterz@infradead.org, mpe@ellerman.id.au, linux-arm-kernel@lists.infradead.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, pierre.gondois@arm.com, dietmar.eggemann@arm.com References: <20241220075313.51502-1-yangyicong@huawei.com> From: Shrikanth Hegde Content-Language: en-US In-Reply-To: <20241220075313.51502-1-yangyicong@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: TecHftRr10EKN3_ENZX2-3FGtFYZ8j2N X-Proofpoint-GUID: TecHftRr10EKN3_ENZX2-3FGtFYZ8j2N X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-15_01,2024-10-11_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 bulkscore=0 spamscore=0 priorityscore=1501 malwarescore=0 phishscore=0 adultscore=0 mlxscore=0 suspectscore=0 impostorscore=0 clxscore=1015 mlxlogscore=904 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2412260079 On 12/20/24 13:23, Yicong Yang wrote: > From: Yicong Yang > > The core CPU control framework supports runtime SMT control which > is not yet supported on arm64. Besides the general vulnerabilities > concerns we want this runtime control on our arm64 server for: > > - better single CPU performance in some cases > - saving overall power consumption > EAS is disabled when SMT is present. I am curious to know how power saving happens here. > This patchset implements it in the following aspects: > > - Provides a default topology_is_primary_thread() > - support retrieve SMT thread number on OF based system > - support retrieve SMT thread number on ACPI based system > - select HOTPLUG_SMT for arm64 > > Tests has been done on our ACPI based arm64 server and on ACPI/OF\ > based QEMU VMs. >