From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.19]) (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 EF5581BDE6; Fri, 12 Jul 2024 21:56:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=192.198.163.19 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720821373; cv=fail; b=fbmFC6gAkWASWaP/H5zk4AjysXfa69vT7mHN3WU+Te21KnfrPMymOgKKboYZb6nMrOsracWd9D/b3yhjmfQsLO2wLQDS3/tkiliC8KMQYVMCc52yLIO5oOXschj5tUMD6KD7MgEMrouvg5y0cOdK9ieXgQCDlrLwwsC7XHuK/bI= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720821373; c=relaxed/simple; bh=jJCRwJxoosLbrVfU3VcyrnOylMm4SMC5AgN8574Hboc=; h=Message-ID:Date:Subject:To:CC:References:From:In-Reply-To: Content-Type:MIME-Version; b=QMerxxmRDoyTScgNYgvFPsR7LfBgcUyEOrZ2ZyiTke+kMgCwpiolqYK+DahnmyxNVJx5iekoZceA4mSx5maA+kxDqJOj4lTyJW2Nt4mADG55lxAMBuP5kjBdEoqQJyfBjyznC259GYVPFy5rULK1bsnm4DqaqaAXHp+b24QY63g= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=bFgM5xKk; arc=fail smtp.client-ip=192.198.163.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="bFgM5xKk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1720821371; x=1752357371; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=jJCRwJxoosLbrVfU3VcyrnOylMm4SMC5AgN8574Hboc=; b=bFgM5xKkLTJBY224TxX1OGgjM6i9nyw92UFO/MVi8t0vIlAX5tYHYeJV oc9k8FqxaTfryHIGcG5ZvZFtAsnzBg2q39/XTEV8vY++qsXSOKU1CoBBC ZX9aam8mH3YEnK6wVmJZIEDCN1OtHm3QmgqxujysF2MEqP0bMxbUFnhNl P0difB6sr7zTYHnB98Mk8pTTRkEO4+r2GwmESgogEa5EKKA3nglnqIJoQ cDcP+0Uxv6PqZVqx0zktsig+0+eFzfvdAknZEWRB2hyuTGsCOsOJwsM2W H3pXO3HJ/k5cwqJTAmgoGexTNiqbLyo6O5aePyqZ5OeEZ2B+VCzc2qNd+ g==; X-CSE-ConnectionGUID: 3hQzW5xdQ+CFvnps+ovr2g== X-CSE-MsgGUID: GvgbETt/Rw28VKe0+tCpaA== X-IronPort-AV: E=McAfee;i="6700,10204,11131"; a="17992531" X-IronPort-AV: E=Sophos;i="6.09,204,1716274800"; d="scan'208";a="17992531" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jul 2024 14:56:09 -0700 X-CSE-ConnectionGUID: xepB+ubRRDWuUZc/VFbnnA== X-CSE-MsgGUID: n0PK5u3GRBS5mPZRA6mSKA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,204,1716274800"; d="scan'208";a="53868149" Received: from orsmsx602.amr.corp.intel.com ([10.22.229.15]) by orviesa003.jf.intel.com with ESMTP/TLS/AES256-GCM-SHA384; 12 Jul 2024 14:56:08 -0700 Received: from orsmsx610.amr.corp.intel.com (10.22.229.23) by ORSMSX602.amr.corp.intel.com (10.22.229.15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Fri, 12 Jul 2024 14:56:08 -0700 Received: from orsmsx610.amr.corp.intel.com (10.22.229.23) by ORSMSX610.amr.corp.intel.com (10.22.229.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Fri, 12 Jul 2024 14:56:07 -0700 Received: from ORSEDG602.ED.cps.intel.com (10.7.248.7) by orsmsx610.amr.corp.intel.com (10.22.229.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39 via Frontend Transport; Fri, 12 Jul 2024 14:56:07 -0700 Received: from NAM10-BN7-obe.outbound.protection.outlook.com (104.47.70.48) by edgegateway.intel.com (134.134.137.103) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Fri, 12 Jul 2024 14:56:07 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=lbPbOs4uWL4jwZpTgu8epuOnGcqEfsIW6O+yzBvgZ24RJexoxnI2DJM1YpOEh3LbC/WOI0f5khRAAzmSq6W9w5nQ+Dre2YG6NoRdep8OH+HJpUXya0rk7o74J5SlNle3hYnbu5CP9iIJ1u9ctETgcjM4YwbneyIqHi3uIZaXmh2lI8hpuaFK1KyPU+P+wQrFC94NI5hk9SrhftUUldvymUNYoFcl2fuNH7j1K2w0SbPYoU58q3XICsxlwGJxty5UbvE6YO3mGNz0plPcXZmlLuscJ4M1JuMcGLIi5xuZRBuvpj8QOdDsRb5GM6K+6VFzeSdm/hWxNSob22vwRKBghg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=casLdDwlUg1V2W7mFdqObOMhUFq2soiqjgLfwHqrySM=; b=d2EcY/TG5ieaN3Ims0mUzEQi0BlPJDVTSbojaSQ6BVbUM2GPxTa+pV3JcihoSWCoNMQT7f7GFHNvA2ZyMIOXyFO9A5xoS7yoU4jbFLbAuaqBiRklzK7Mgkp3IFtYHT3E+TP3y/t+cozrPShrjX669xttFhdmsLf32zK4oeBYnyYyAJZ4UrVDgHiMUlHO6qIlI6QeLYX+Jg/0DHlClagGrjkKvBxUb9vEpAEuVbQZ9+j0s0GrMSQbPd7FceKrOz192pE+oy2lIJ2nH16kTXKjtUrER7M/hIsx5ATTd+yJe7Kyx2alt4z546JmmF5JuenfvBnCw33TjzRegasexvzM1Q== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from SJ2PR11MB7573.namprd11.prod.outlook.com (2603:10b6:a03:4d2::10) by SN7PR11MB6725.namprd11.prod.outlook.com (2603:10b6:806:267::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7762.23; Fri, 12 Jul 2024 21:55:59 +0000 Received: from SJ2PR11MB7573.namprd11.prod.outlook.com ([fe80::61a:aa57:1d81:a9cf]) by SJ2PR11MB7573.namprd11.prod.outlook.com ([fe80::61a:aa57:1d81:a9cf%3]) with mapi id 15.20.7741.033; Fri, 12 Jul 2024 21:55:59 +0000 Message-ID: <1c51aa93-5b86-4361-87d5-3d5d48fac4e6@intel.com> Date: Fri, 12 Jul 2024 14:55:54 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 01/20] x86/cpufeatures: Add support for Assignable Bandwidth Monitoring Counters (ABMC) To: Babu Moger , , , , , , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , References: <724d0234ca56d71f9d8d893806870181d027f556.1720043311.git.babu.moger@amd.com> From: Reinette Chatre Content-Language: en-US In-Reply-To: <724d0234ca56d71f9d8d893806870181d027f556.1720043311.git.babu.moger@amd.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW4PR03CA0123.namprd03.prod.outlook.com (2603:10b6:303:8c::8) To SJ2PR11MB7573.namprd11.prod.outlook.com (2603:10b6:a03:4d2::10) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ2PR11MB7573:EE_|SN7PR11MB6725:EE_ X-MS-Office365-Filtering-Correlation-Id: 0d8aa3f3-c1a5-4325-6326-08dca2bd69d6 X-LD-Processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|7416014|366016; X-Microsoft-Antispam-Message-Info: =?utf-8?B?anNQUVFTdUpxc2RuQ3htVkk3KzZjSUcyTlFqSnR5eTU4VUt1eVRacWUvMVNY?= =?utf-8?B?VFZCSmNGZ0oxb3FsRlNTSTI2c0kveGJLZ282TDVlZGdNdkxtNHRvcjY4aFlk?= =?utf-8?B?TFZHZjFFNlQ1ZkwvR1BEdWdEZTFUZUZQSGx3RWpiVXN6Zk1TV0FkaWJyYnRK?= =?utf-8?B?SmtUVi9qWXpWbmszakRMYldDRzlnaGp2bEVBdTVQMEVPL3BlYllGTlBFa0Fp?= =?utf-8?B?U251TkpkL1ZBaFdVWEwwME11VmlyK2NUMlM3TlV6Rmx4eEplZXNIVFVmOG9w?= =?utf-8?B?NEx2dm1lVjdrdVJiZ0ZkMWM1OUtSSUZneFRxdk1pSGEvUlhpcWJyVWFaYU02?= =?utf-8?B?d1VXQXZ3NjQxVTdVMnZYdjNnNU9yOXdxYW5wQ25aVjVja2VITlJSVjNHVjVB?= =?utf-8?B?MnlpSk1CdmRqaXpvNUk4YnVRMEpaaWRCUURnVjAreUJHZ0VVZjExT1NrbHo3?= =?utf-8?B?cjNYUThNYVlTZkRZNGpwREp6dVhGYVRaSEdYaTc4UkJwbTAxUnU4SnRuUjV2?= =?utf-8?B?dU96ZGJ0RWIvYkFzUWsvakdHRENZSnZKMTY2Ty80eUdabElJb2Vtcy9VaVJw?= =?utf-8?B?cXU5cUNvWkRNU2U3aHZUeG5zRlBJd054ZjJXWWxqVm5vZFBlTGdyb1V3L2dv?= =?utf-8?B?ZE93SklTYXhsY2ZLc3NFcmxLSEFNcVZ1ME5vQ1VWckdrNXVOMnNmS1RRMzNI?= =?utf-8?B?MlFTcVFIU0NzYUdRTWZQb1IvUHhSTnA3c2dSWDlhbHNzRG1vVDIwZzd4cFR3?= =?utf-8?B?dXFYemV3ZFlzRmNrRGRORjJSWTY0QkVqRE03SWprbFAxZk5GOGdONGJxYjRS?= =?utf-8?B?WENZZldKK1hDNjgwMlpub0tBSi9NUmU5QXlQdktyd0ZBRHR2Y2JJWWsxbEMw?= =?utf-8?B?K0FQRW9OK2VsMmxoNlJ1SjFNVDN1UUtkZlJMUFA2V2ZDYWhES0RxZXhSZC8z?= =?utf-8?B?WXRLZ2VFM1ZDRU9EVTVNODhpNit5NXhsOFBIV0xuak5Gb3VxRHRvNlRPanEz?= =?utf-8?B?VTF1dXdKOUlMWkFKTDJSZUphNDZ4czlMc01YSk4wNGVtZ2dSOXE1SDhPaTFi?= =?utf-8?B?d0V5bVVHekNqMk1VZWVTZ2xJNDF1YjR3Ri9sNGFZWUhMNnRaWTJ0NWx0TlRw?= =?utf-8?B?b1ZCbFFmVG5XNWZGQ3ZYbVBoUFUzVldVN0ZtV1dod0diWmxhZ0Frc21GNldF?= =?utf-8?B?SGRRcFBxVVRBUjdLWGJEQ1g2Qk9BZGphUXlqZldCa0RvMzFrNnpTaVBoa295?= =?utf-8?B?TkxVMkJnTlg2WWJqMitrUDVpZ0wyNEE5bVY1SHlObURia1hpQi9LMktyM1Az?= =?utf-8?B?Wms1SEFIei9aTkt3cFR0SStYV2hwWUZISWtyZHFzUkl3TmtGUExnbG96ZWg5?= =?utf-8?B?bzhVQUl0MW10cnl4c2ZMZzJPQkZCekdLaUNoM2ZYU3EzNm1COXI2VFNNZTZQ?= =?utf-8?B?YktPS3UvaCtMVGZWZ2tpMDQyTVBBNkFxdGRySUFXMDNIUzhaSi94NDJOWVdK?= =?utf-8?B?RTJOTXExbG5kMlRsYTlJclVhMFo0alA5UFcvU2FsdHNJTm9tOHhUOTlxYisr?= =?utf-8?B?UXBCVHM2M3A0WG0yUzJvSkF1aWNZYUhxMXFoQ0Vmakk2OUVIblBEbGI3S0dU?= =?utf-8?B?enA2WHhJUDFZWUFWRmFpbTFMMlM2TjJOckF3QitBUU01bDFNYjcrVDdBd3Zz?= =?utf-8?B?K2F3M1V0UU5GeTd6RzBrUVMyWXJYcXgwZS9kRUZjeFVYY1BPUWk1TWhPTUNB?= =?utf-8?Q?IwlnRywZ5tY0zm7AEw=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SJ2PR11MB7573.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(376014)(7416014)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?NTlWUW4vUHZ1RkppQWVJYUk4Z0Zza1hBOGRLOTVTWmtEZlNreTIxWTBjS1Bl?= =?utf-8?B?RnVCZ2RZbTFhMHU1c1JpNU83VFRQVlFoWWk5VEZkOVVmR0VTQmcxSFFsd0c3?= =?utf-8?B?b1VIQ0F0ZVJNcjlKeHllOVpneHJoNXJMUXBHSmQybEI1N2ZJMFZRY3RPajRF?= =?utf-8?B?azJhQnM2VXEwdUpRQmIyRTRtTzdLem1DdkFoZ3hJWGwzWm9RN0hiNVJDcjN6?= =?utf-8?B?dXlEWmNTTVE1TWZoWTQ4dmFZUWtJTkN4RGJleC92dmdRSnBpcTBsZ01SbU9m?= =?utf-8?B?bW85QjhEY1NodjZYeHN0dGVkaFk5cFY0NzJnUUh1LzZUWGJrUmY0M1plbFU2?= =?utf-8?B?YnFrNHVIdTJENktHZEJ6V3M3Tm5ibkt0STArYy9iclZMSGZIRjBRS2Y3NVNB?= =?utf-8?B?c0orQ3lUeGl5b0JUQ2JkSU5rMkZkZS9zUlBZdnUzOGtiUGVIdU54d2tNVkVS?= =?utf-8?B?RHhDK3IvMVJua2F2d0xybXA5OGtUWTNLNnI4ZThRNWdCS25PZmJpUHRIQTNV?= =?utf-8?B?ZlIxTjVIL0tiV3ZPSHZpSDFTSWtCVEo2ODZMdEFLdGd3Ym5jYTl4NjhTMSt1?= =?utf-8?B?VGJlL2laalBRcU9zVDV1RzF6Sk5EOFFIeVhCdmxjcTZxQ0ZKU3RGc0hZcVNJ?= =?utf-8?B?UVlYa3JPZ3NNOFJrTWMyZDc1RHFnTHNvVFg2ZTl1TWh3REdhT0FpMmE4REJq?= =?utf-8?B?djh3ZXNLSnVGMUxjd05yTUh4TUxqUGVjQkpQNFU5dDRPQmo5REZXcjF5VXNh?= =?utf-8?B?UlRmRjA4ZVpRQS9tNlJ4NjFyRjFERVJlSHc2RjR6M054SkY2VmN0c2Zwbnhi?= =?utf-8?B?dWU5ZmFuaUxqS005YUh5Y2JVdndYZm9BNjZvcmZ0aWdMaHZ4ekZ5OU02NzdI?= =?utf-8?B?NXJMUUdMaFBudjJGUVlhd21nU1ZvZkxKU2t6aWxtWDZnZ2lmOE1VbWdOR2to?= =?utf-8?B?VVpjUmZOdnY1N0pLSVN2dXFPMG9rcjFaTVN3Rm96SkJ6TXVPUWN3cHViYm4z?= =?utf-8?B?YWYrYTlNOHdkUFFPNTJXbjZ0YnROK2Vta29kMVNEMzM2U1JvVTFVNUt2MXpn?= =?utf-8?B?RmI5UVV1SkNhTi9SNUpRRVZhczVHWWsxS2wwc1pUaUNjc2FiNVY2UUFsL0FI?= =?utf-8?B?bHQzeURjOWRPODNhZW9BcFp0TnFiMHh3NVJVdCtyQXZ6Mm81bi8reWQ1bDZL?= =?utf-8?B?VHNRNlUxNEN5Y0tudkhXb2tFOTM5SVN5V2taSEpmUTc0TFM1ZnNqTldtK0Z1?= =?utf-8?B?K2UwdkF6c1hORkJQMnJWSFFFWVZUNkxSK1doMjU2OWljL2RYQXBabU5JY0lZ?= =?utf-8?B?RVAxR3VPcG1XSGdGbWE3TVJCbGF2WEdMcVcyUVQyeFRqTFFLbk93cWIzaXhQ?= =?utf-8?B?K2x1ZVFoT294SUZtdldHcGZHNFRJckJpWStwY3h5d0dtS01TdFdCNTl3aVNE?= =?utf-8?B?WU1PUWE2N1dXUU5LU3VoSk5KWU1EenozWFRxd1RFMFhqK0xBUTJESk93c0dW?= =?utf-8?B?MkszUUZnVnNFTTJlWUZIWUI1dnIrRnMzd1J6dVFkMi9DaGpHOW5FQUJ3aSt5?= =?utf-8?B?aTZlcmZmbnZQK0JCUWNMd2crQTdVbEhIR25zMkZmdUp4dE1LeEtRZFhRNzdZ?= =?utf-8?B?anRlRitWYnN6ZDNKRElUTW9CUFJJQm9RcHFkQ0RQTElyc3RIRnRiSERRRGth?= =?utf-8?B?aU9zU3hRNXhoUWZmWE9qQ1MxRFVmajQweFlEVy9KSmJPYWVGU0JxUnQ1UHJy?= =?utf-8?B?WU0rTUU4UXptdUwyZmpRMGdPNmhPRGt1blhzNG9Pb2s4SVhyV2hJUkZQZjBG?= =?utf-8?B?YnBrSmxpaCtyWStySFlSWXBoTU5jLzFzaW8zdDgwb2xaMHZ1YjRubzAzclh2?= =?utf-8?B?aGJlRy93U0lnYlFzS1Jkd3NsUFU0TFE0OCtWdzNpeEgwK08wV0VKVXpQSjhS?= =?utf-8?B?RXpYTWl0VE1zUmhjaEZuVXZEWTMvYnZWbm5ZSmJYSnN1TS9Oem8rUjRleFc3?= =?utf-8?B?NGtoTEVKanVIblYxbTk0ZXpJbGlOejZUbzdvT2RxUlFyWUkvWkdpTW1pTklr?= =?utf-8?B?eXJremw2ODU4VExBcVBuTHFiWTQ5UWNsSEdMWThDdnFrMWVJcCthdzBmQ1lJ?= =?utf-8?B?dWRhRHRSaDdGUkdmcWFlWENwVThzVkQyZkk0Um5WTzFxaDZGdHM3OHlNRTRa?= =?utf-8?B?Zmc9PQ==?= X-MS-Exchange-CrossTenant-Network-Message-Id: 0d8aa3f3-c1a5-4325-6326-08dca2bd69d6 X-MS-Exchange-CrossTenant-AuthSource: SJ2PR11MB7573.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Jul 2024 21:55:58.9587 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: i+8vLRzz0Rpbg8oQlExuHZPGssKdxxDGv9W0wxdyz/RCoTMbCmWWbU9Ch+jxEOvbg0Uvn3yeeveAGAWaX8eLigGJblJEFiG4EcEBi26y7EM= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR11MB6725 X-OriginatorOrg: intel.com Hi Babu, On 7/3/24 2:48 PM, Babu Moger wrote: > Users can create as many monitor groups as RMIDs supported by the hardware. > However, bandwidth monitoring feature on AMD system only guarantees that > RMIDs currently assigned to a processor will be tracked by hardware. The > counters of any other RMIDs which are no longer being tracked will be > reset to zero. The MBM event counters return "Unavailable" for the RMIDs > that are not tracked by hardware. So, there can be only limited number of > groups that can give guaranteed monitoring numbers. With ever changing > configurations there is no way to definitely know which of these groups > are being tracked for certain point of time. Users do not have the option > to monitor a group or set of groups for certain period of time without > worrying about RMID being reset in between. > > The ABMC feature provides an option to the user to assign a hardware > counter to an RMID and monitor the bandwidth as long as it is assigned. > The assigned RMID will be tracked by the hardware until the user unassigns > it manually. There is no need to worry about counters being reset during > this period. Additionally, the user can specify a bitmask identifying the > specific bandwidth types from the given source to track with the counter. > > Without ABMC enabled, monitoring will work in current mode without > assignment option. > > Linux resctrl subsystem provides the interface to count maximum of two > memory bandwidth events per group, from a combination of available total > and local events. Keeping the current interface, users can enable a maximum > of 2 ABMC counters per group. User will also have the option to enable only > one counter to the group. If the system runs out of assignable ABMC > counters, kernel will display an error. Users need to disable an already > enabled counter to make space for new assignments. > > The feature can be detected via CPUID_Fn80000020_EBX_x00 bit 5. > Bits Description > 5 ABMC (Assignable Bandwidth Monitoring Counters) > > The feature details are documented in APM listed below [1]. > [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming > Publication # 24593 Revision 3.41 section 19.3.3.3 Assignable Bandwidth > Monitoring (ABMC). > > Note: Checkpatch checks/warnings are ignored to maintain coding style. This note may be more appropriate below the '---' separator line. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 > Signed-off-by: Babu Moger > --- Reviewed-by: Reinette Chatre Reinette