From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (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 1982D537E9; Wed, 1 Oct 2025 12:14:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=198.175.65.9 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759320842; cv=fail; b=LE6LYv0WNWy1ep7Wde+GF+fPSs//edy2OK7BARifkPFen28VX2Kp5t2VQtUyN2JhONImLzrJQxaEsq8ugpKeYtTRsUY/Dt3bDzMxEEkNEDH3sK7ofGgHLDD5YGVtqNTYPIuj5fF7UdbvoRqEqSVJgL/t3iASXP+rHNEVsIUXeQ4= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759320842; c=relaxed/simple; bh=nh9IkIzTrR1UlSE6zgyWqKYf1TMU7r0/ZmHlAX6azwI=; h=Message-ID:Date:Subject:To:CC:References:From:In-Reply-To: Content-Type:MIME-Version; b=jd98XTupZePDx7wsSSjx//eBl/ZKGppQWrY5sl5Rvk892SWl8iSbQdG2aERCGhSw1vpX3YqxA4EGWJlYK8F7HYSVXybbesYLzSJtcXf6ig7rakSADN2oGPZSuNYFWd5U9fTGkw8Y5vXJp2roWrZ3PfR8wMH1Fx48WHTmlcsAjjE= 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=knEePYVN; arc=fail smtp.client-ip=198.175.65.9 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="knEePYVN" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1759320841; x=1790856841; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=nh9IkIzTrR1UlSE6zgyWqKYf1TMU7r0/ZmHlAX6azwI=; b=knEePYVNpx4Kdyk0a0BZbuR4Je8/gpT6h+ZcPBgAZHIFxKLPLwED8uYq 1mp5F8WgnLlNOZF3rN3pP/c/OqhBP9MJVUjDbkCTrQtwRuimdCjlDuARw +aWvOXy93KBgpfyk6y8JgMV7lBKRpYZjfK01DS/hLzFjSFhzkEgV3q6a1 8WkSzhU/k+3fJ60Nepe58ys/SX/n6laPkPiI8v39/6+q+gabSYktR3Eun mvV+vFNnl6yx2Boe+M3TQlbfEFq8NUEgnB0VUT2SE/mZOUMZLszYJvd86 Vx08rJpU4epjdJueSTO+MQkWOS7ySWZ8a5siQGwlVmPG7ZWfS1R6abW3a Q==; X-CSE-ConnectionGUID: rTT7z/rST/iy/MHUrRk7mg== X-CSE-MsgGUID: myBiUwlhSf6rolGw+QYkPQ== X-IronPort-AV: E=McAfee;i="6800,10657,11569"; a="84211076" X-IronPort-AV: E=Sophos;i="6.18,306,1751266800"; d="scan'208";a="84211076" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Oct 2025 05:14:00 -0700 X-CSE-ConnectionGUID: g0TAFL22RECH/LBbrW8LOA== X-CSE-MsgGUID: 0xqurrxEQ1eKzXT3TOm1Fw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,306,1751266800"; d="scan'208";a="215898256" Received: from orsmsx902.amr.corp.intel.com ([10.22.229.24]) by orviesa001.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Oct 2025 05:14:01 -0700 Received: from ORSMSX903.amr.corp.intel.com (10.22.229.25) by ORSMSX902.amr.corp.intel.com (10.22.229.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.27; Wed, 1 Oct 2025 05:13:59 -0700 Received: from ORSEDG901.ED.cps.intel.com (10.7.248.11) by ORSMSX903.amr.corp.intel.com (10.22.229.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.27 via Frontend Transport; Wed, 1 Oct 2025 05:13:59 -0700 Received: from CY3PR05CU001.outbound.protection.outlook.com (40.93.201.43) by edgegateway.intel.com (134.134.137.111) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.27; Wed, 1 Oct 2025 05:13:59 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=J8EX0Wk4cB/ULyH7+p9SlGKHB04lIpKoFYQ9To5cd1eABc0eDTJv8udiFKlf94TTlKxAA8kMmq3cpZxbdNAP3pcs+kWCbtTkRXtu/CxzaDNIdwOOYWFZABgmIPdMbYLIGct360Q1S3rGMAcMfmt36xh2lUOcrOLWe9+KsmafWg6F8TfUrcaCBIzKWRIinkKxn2k7uREc6Hoq69hVdtP+NUeVjyejTwicATXPM9/BW7R+BTkaHMgUISdRyBtv/C0xonUfQ5ayl5Br8ay3JseITIY53mT/CUs0ieRp0gVOup8FHQOLtfLDvru5TB5I3sHQP0ezQqDFcBpS3juRjKO4Yg== 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=9KXD8ZwxVQZEWTjtOZch7eiJVf22oCuEFtRiKQ787p8=; b=OqSmGFz3nzna/5DspGgWnRiEGYqObyMwBDlGuO09P2XZYPWVm+BXAr2CJapAxVP4Rbf0FAjay5Fe0UAsND+1UIxZvib3jnYs3wwVSj2DOy7u9hG6oMZlW2JOdRZ0/HVZBMcCA8md1ggW9YVNyErRwrsZfl8qvJaE7kK8osjYfqHJA06eGP5oBCNdkE8Zl/uT8qCM1wqw4EIvjC7gC4u7G5ddyzX+XK/LuuyA9PPpelrtFF5G1dUKRFHmxEsH8CKUjIa5SBe1+MNKraJXYpfPyt2iPDGsLhALuk0w7UTNv6x1qm+PNAObrXpvHayt6Lrxo/bVeTFCABIlSemMVXF7mQ== 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 DM4PR11MB6020.namprd11.prod.outlook.com (2603:10b6:8:61::19) by SN7PR11MB6899.namprd11.prod.outlook.com (2603:10b6:806:2a7::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9160.17; Wed, 1 Oct 2025 12:13:56 +0000 Received: from DM4PR11MB6020.namprd11.prod.outlook.com ([fe80::4af6:d44e:b6b0:fdce]) by DM4PR11MB6020.namprd11.prod.outlook.com ([fe80::4af6:d44e:b6b0:fdce%5]) with mapi id 15.20.9160.017; Wed, 1 Oct 2025 12:13:56 +0000 Message-ID: <38569247-431c-4b0c-af0f-aadd6fb26849@intel.com> Date: Wed, 1 Oct 2025 20:13:45 +0800 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] fs/resctrl,x86/resctrl: Factor mba rounding to be per-arch To: Dave Martin CC: "Luck, Tony" , , Reinette Chatre , James Morse , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , "Jonathan Corbet" , , References: <20250902162507.18520-1-Dave.Martin@arm.com> <02647276-dea2-47b5-a271-7f02666e0492@intel.com> <541fb538-0c22-4ad2-9c6e-83ada7f2240b@intel.com> Content-Language: en-US From: "Chen, Yu C" In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: KUZPR06CA0010.apcprd06.prod.outlook.com (2603:1096:d10:30::12) To DM4PR11MB6020.namprd11.prod.outlook.com (2603:10b6:8:61::19) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM4PR11MB6020:EE_|SN7PR11MB6899:EE_ X-MS-Office365-Filtering-Correlation-Id: 8e38f83c-e7f9-42ca-2a2a-08de00e3fe41 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|1800799024|366016; X-Microsoft-Antispam-Message-Info: =?utf-8?B?NmlWZzVTeEZvdjFoQ0xqK1dMZHBlRjFvTXNhRDFkWWI4R2F2YkgycSt4WXJE?= =?utf-8?B?VEtCeWZiLzJ6YkZaMlV2QkJ3UVNrWWpUMTJaRGlWSFBEM0I1MHg3ekgrVUhS?= =?utf-8?B?VW9UaGdmV0gvUUl2ZlRQYTR0cEVIL2NLOVJ2TkpuZkRsVzR6Y1hBK283MEpz?= =?utf-8?B?TTJEaHRxdStZdmdhV09FTmxRZWNmVnRUeUNucWdQdHY0cTNBajNBM1ZUb1pD?= =?utf-8?B?NU9mTEJnaG1Ha1I0RGlWbngzMW42enlXeHkzWVRUaFE3L2o4Z1hFWHVsM2I5?= =?utf-8?B?NEI2YnRqZGlLRVY3WkhQak1aQ3ErbU01VDEyaGdlNDMxRDVBOVVxRmRXclp1?= =?utf-8?B?VmxER01GcTRVdHVWbWNYVUNqb0Uwa1BmN3UwTUo3RWtvKytJYkMrTXJ4cFpM?= =?utf-8?B?OTBxUWdGL3pKTHBhOFVpVllsZTBJaHlNQUNLTTlqaW5PcVc4c1Npc3VJc1pQ?= =?utf-8?B?ZlBteStpWHk3RzBRV1pyVUVuT2hVQXZIMGZVMktzMlkvUHZNUDgvNEVnWmcw?= =?utf-8?B?S1h0R2NOSnIyWjhBOElIZWVodlIvcS9WcUJieU5xZTlWUThCNjFGbm1NZE5U?= =?utf-8?B?VnhlaEJVNWpPR2VRM3RlTjJxWkZWUk1WaWpmV29jZllVQ0VDRmdYaDVLM0xl?= =?utf-8?B?MDQ0UkMrUVpIKzNEWmNlNDNxTWIvOE40bndPQU42UzBtUG1uWHQrdGJzK2ph?= =?utf-8?B?K1AwNTNWenNlWk4xWlU2TGdMTUlzeWhteFVNVkxzWnhBMUdwckVkUHQwaXps?= =?utf-8?B?ZCtxZ21zbExLYmNFV3ZYMXVrKzJ4NW85bFRuVmZ4MDczTGxOWTd3ZzczUi9Q?= =?utf-8?B?d1NSSTV2aGVJaVhtNytIc0lEVGgyZ0pJZnVCRkU3QU10SWFmTytLc3RRZFVo?= =?utf-8?B?aVN2R1hyTXZHaHl2Wkk1QkR1MzExT0dZZWpjeEZPbWlWbVE4T0RNNUl1SEow?= =?utf-8?B?Y28wUHEzM1EyNkErUlNyK1RLeVk3RnQxTmJRVExrRXpXR281R1lrTktsK3NY?= =?utf-8?B?d004NEt4VUVabmllaCtTVnJUVm9QSmdLQWJMSVBhK21Ub2x5Y3c0bzFQMDVh?= =?utf-8?B?Y3lvSU1tZnBiaXU4NjBldjhKOXhoS29EbWczSmtqRTZMZ3ZjSlhNYVRTSkxB?= =?utf-8?B?ZnkwTFVpa0p3dEVJSXBLTytTNlcvRnVDa2ZCVXpwUXhGVFRiNEd0YzZkMmor?= =?utf-8?B?MFVLUTVUOXpQbHhUM2FVRDcxSmlDYTRENGczbTBmTEZxMzVrU2gvM2pPYnJX?= =?utf-8?B?TnRQY0R0VFgwQzhFWDEzdk5ZQ1lXejFTUy8zdFIvSUR0TU5EZUp1cmN4bDJi?= =?utf-8?B?MjdaS2NWZTYvcDFjSGdGZWptbnNDUXl4eU9qQ2M3am50cmhTRCs5T1hva1lm?= =?utf-8?B?TXRvVGthd0p3dlpRL1dsb2hPZ1EzUlpZR3dDZWNralZHUTMvZmhNUXB5UkxN?= =?utf-8?B?bzZiVW0yeFdreUxlWktZbmlIKy9QZFpNNTZ1QWFqV0t2R3VXTDliVERsMG44?= =?utf-8?B?a0o1RHk5d2hPdnhvVDBkSlhqa0hhWFpUMUVoWGllMm1uTUdzV2JUSGJMVFpJ?= =?utf-8?B?MFUxb0VYb0R4czh4N0RJZ0w4R3R6SkJ3bXQ2T3MzZnZvUSsxTVk3TkRoZm4z?= =?utf-8?B?cE41UkhNclBDaFQxdW9wMG9QS20vWGhUbStjUk9pTy9DZ0pqU0w5cXBjaHpl?= =?utf-8?B?QkpYek5SRDRWT0xoZzFLekFwVGhwUWRBKzJWckpYVnNVOGI3QmNkYkhNdG9s?= =?utf-8?B?MjVseTV3TnV0bDhjemRlYmlNK1Y2WS9OZHdkbkpwNVl6YWFScTdlSUtaYmx6?= =?utf-8?B?QkRaOEZQUDlQcWZIWmxNeW5NODBhZml2L3BOV0RxZFlTZ0R3aHpBcW1pMjdu?= =?utf-8?B?RWhWRkh0KzdtWDRmOG1oYnNBdVZTM1lkQ1BjanM4T2g0VDFMNVIwUVdTUjZy?= =?utf-8?B?Q2YxeFpMSjQ2U2toNmxzQ2FQMkRudnEwZHNlTmxveTFNQnlueFpENlVJeHRM?= =?utf-8?B?MTFHY05lWHZnPT0=?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM4PR11MB6020.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(1800799024)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?S0pmWVM4QkRpdFBjaWtBQjlYOHZJc0V0VFFoQ1JHKzZENkxhVXJiKyt6S0pY?= =?utf-8?B?YTR6NVJHUmZVNUhsR0t3akFBSnVPSEhwdDFXUDViTEF6UHNLQi9SdzFxTFls?= =?utf-8?B?SC9Za3IrYnFpZGkvSEJCM3pwMW1tbGxsK0dWbk85blJnWlE3NXBiUFJhdHFR?= =?utf-8?B?Qkp4dENDY1cxZTdoa0FLaWMzWDB1WVBkdnNpVnlPL0hlbUhrb25zSmgxNnNy?= =?utf-8?B?ZW92dkYycElmZWhLYkFxTTA1enBJb2wrRllLZGhzRFBUbFQxM2hnOGdYdmVI?= =?utf-8?B?SDJSeng4cnhiUXhxZUJldjhjSnpGU0c1dXNTeFZ1QWozUkdFaUIybFo2OVNJ?= =?utf-8?B?QW9sMktPYUM4bkVXbUtiN3B0T01qOUlpK09HT3czSWR3QXdJaHhHOXdjR0hm?= =?utf-8?B?MGIwWWlSTnpVMlY0cWRhTEhZZjhIcTVCMHpvQ2ZPYmhteFlMQmYwNmhidTV2?= =?utf-8?B?anpEemZMVUVkQXNGTEZvYjg2TXVBTlhpWldxSHhMbS9kN2pNQkRTY2c5cE80?= =?utf-8?B?N0c2eDlSYlhiekVTbVo3M1VxMUN3akoxaG04YXNuYU1hcW1hUk5GcnVJbitz?= =?utf-8?B?cCtCcjdtV1RLRGRlSkY1ZWM5aUp4S2RwNHlQZGR0WjdJekZpRVIvMUpzdy96?= =?utf-8?B?WlpFNkFoK0pZVmpucVNvZytmcXA4dlhPOXF0WnoxTjQzdVl2OGlHTHVzcjAz?= =?utf-8?B?d3hTaUZBc2VBWXVjeWdDRSs2QVdrdGNyRENkYkNFdXQzVFRtRUVza29LeFZ6?= =?utf-8?B?WE9Wc0JDMUNKc0cvZFIrQUZUclBOakJYNy9SSFBHcEFrT1NTMks5ZkhxZ2hE?= =?utf-8?B?K0V3bHFTd3publFEZk1kZGJtdE1IWENHblFhMVhnL0lnRUtkZ0pGTUx2NHE5?= =?utf-8?B?bHZ5OUs0ZndDd0lJVEJ2cDJhbEkzTEEyclExTlhKSDJPTXpSdkl2eTdnQ0tU?= =?utf-8?B?RDh0MTVSelRmQk41Zlp2Zy9xS0F1Z09hWXNLWVphMEpLUFNadmtFeEk2VWZN?= =?utf-8?B?ZlczbEFCRkdRcmdMZXlaNGVCYUFxcGRUd3A4YW13QlNEV1Y2TE1PNThtSlVR?= =?utf-8?B?eWlvTWYybkNnRmQ2bTE4MmkzdktCaFNvNXMwdTdrcnNnVUhSS2FWS1RyN08w?= =?utf-8?B?aEd0VG5vRDhJeEpwbXIrUXVrbmhZZ25ycklrY2dsbWlNdnlwL2JMYlVSeW9M?= =?utf-8?B?ZUwvTzhDdis3WnBJa3B0THpvT1Axbkh6ZERZeVJuVW5nK0NUMzZuVnIxWG5w?= =?utf-8?B?Vmp3eU0yU3JZdTY1NlRDVFRQYlZMSzY4UW1BcDBNM3FNczQ5OVI3ajYrL2JX?= =?utf-8?B?TTMrb2Fid203cW5XRDFKSURXZFVPaVp1WmdDNE5QOFJCZEh3ZWgxK00zeGhR?= =?utf-8?B?OGZCYlJ3NXZKaGRJU1FodEMwVXVpOXlUK3JwY2MrNjhQckZUZ09XQ0tUNnlO?= =?utf-8?B?WEtpeWVWTjNuTUFFUGVhUmxycmI4RjJrKzRlaUgyVzJZci9FVjdIUW9CN2hs?= =?utf-8?B?UDAzMXlIaERBZStpWUtJNW1GYUZHeGMrR29zQitjSUxNTzFjRXVMc2RZTENR?= =?utf-8?B?akRJSysvTGdyVzJDZ3ZsSjB5TVNuMDJUTWtaTi9ZNzUvalFxN1FLZnNwMlBB?= =?utf-8?B?UWlGZ2g4dSsxZWFBZmpVaVZPQVpOWFg5V0N6a2E4WU5DYXQ3azluMDRJVFdI?= =?utf-8?B?dHN6aHNLWXBNYkNvNDNwa29naEJJYjdKR2xlY1Q4NUdrVEZmTDIreGdYV2Vq?= =?utf-8?B?OVNiSDAzaVFGdEN2Qkg2c2FrcnJHNk5WVkcyOUhKYWN4Z3k0TWZTbytrUTg0?= =?utf-8?B?RmdmR2xVZUJ1NkN5NGNVSThyTmZyZGpoc2NveENkZEVqZzE4UTc5WTNGMzds?= =?utf-8?B?VzAvdDIya2VkNk5ZV0pIVlRxVmwwVEd3RmRoM0xCQlc3SUdkL2cvUURGY1BL?= =?utf-8?B?T3grZWdvMHVUN0JnOU04d09mSkpFaEFQYmJxZEZ3dVZDOE5oS3UxWng2UTZt?= =?utf-8?B?VmtXTExVMzYrNHVJaGoyazh6dzFTZy9SLzIyUGEvb3JjZjRJNDdQbWc1Z08v?= =?utf-8?B?N1laelRBOXEyYWt3VDFiV2VycnNyS0d4V2VMNEZGeEFXbFhqZzYzQzVJV2x2?= =?utf-8?Q?9CbDcif+BRJFpKHgCxGWTk5v3?= X-MS-Exchange-CrossTenant-Network-Message-Id: 8e38f83c-e7f9-42ca-2a2a-08de00e3fe41 X-MS-Exchange-CrossTenant-AuthSource: DM4PR11MB6020.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Oct 2025 12:13:56.0236 (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: z1x4qtru3UJpG3KLMkD1xkyUYx6B7OoGEL/HzvdavhMJAAlXtnDRsC8O+JvXWHbuRhc0LouHRzfQsQcUv7X5oQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR11MB6899 X-OriginatorOrg: intel.com On 9/30/2025 11:55 PM, Dave Martin wrote: > Hi, > > On Tue, Sep 30, 2025 at 12:43:36PM +0800, Chen, Yu C wrote: >> On 9/29/2025 10:13 PM, Dave Martin wrote: > > [...] > >>> I guess it would be up to the arch code whether to trust ACPI if it >>> says that the maximum value of this field is > 511. (> 65535 would be >>> impossible though, since the fields would start to overlap each >>> other...) >>> >>> Would anything break in the interface proposed here, if the maximum >>> value is larger than 511? (I'm hoping not. For MPAM, the bandwidth >>> controls can have up to 16 bits and the size can be probed though MMIO >>> registers. >>> >> >> I overlooked this bit width. It should not exceed 511 according to the >> RDT spec. Previously, I was just wondering how to calculate the legacy >> MB percentage in Tony's example. If we want to keep consistency - if >> the user provides a value of 10, what is the denominator: Is it 255, >> 511, or something queried from ACPI. >> >> MB: 0=4;1=75 <--- 10/255 >> #MB_HW: 0=10;1=191 >> #MB_MIN: 0=10;1=191 >> #MB_MAX: 0=64;1=191 >> >> or >> >> MB: 0=1;1=75 <--- 10/511 >> #MB_HW: 0=10;1=191 >> #MB_MIN: 0=10;1=191 >> #MB_MAX: 0=64;1=191 >> >> thanks, >> Chenyu > > The denomiator (the "scale" parameter in my model, though the name is > unimportant) should be whatever quantity of resource is specified in > the "unit" parameter. > > For "percentage" type controls, I'd expect the unit to be 100% ("100pc" > in my syntax). > > So, Tony suggestion looks plausible to me [1] : > > | Yes. 255 (or whatever "Q" value is provided in the ACPI table) > | corresponds to no throttling, so 100% bandwidth. > > So, if ACPI says Q=387, that's the denominator we advertise. > > Does that sound right? > Yes, it makes sense, the denominator is the "scale" in your example. > Question: is this a global parameter, or per-CPU? > It should be a global setting for all the MBA Register Blocks. Thanks, Chenyu > From the v1.2 RDT spec, it looks like it is a single, global parameter. > I hope this is true (!) But I'm not too familiar with these specs... > > Cheers > ---Dave > > > [1] https://lore.kernel.org/lkml/aNq11fmlac6dH4pH@agluck-desk3/ >>