From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.17]) (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 5E7EF2973BD for ; Tue, 22 Apr 2025 18:20:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=192.198.163.17 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745346020; cv=fail; b=Qg7sE3XcfxuKzciLSkUT1ZEl94lOKkKl935Y+4rurZegeGNWyk60HYwDMdfaVNLgXa1EPc/HwqLrEXQWDDcnCN27DM88CM3PbyvQzIilJDWuSDpSNOIIEckaqwF5cv53ZRFUl6X1lQPtyrj4IozM1AXBrXXSBJbjIwvC6p8502c= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745346020; c=relaxed/simple; bh=ktnqDeTbJKD9+UQVxGcgPHmHm/rRYJvwr3sT9xCVLMY=; h=Message-ID:Date:Subject:To:CC:References:From:In-Reply-To: Content-Type:MIME-Version; b=c7RNKGNpjoEAkrPgGNz7G5JMdFO0uIzTWYH3HDigClAlCgyVX3nkAkSDHXpiFrnEo56srgi5bAJksQMJNZfdn+2ZmiIUd5nnUg6kBTRO5RJv/j2YycjxF/GGDogCAU68m8i3KDY/4OOVALtPJtvijPYXVKSOBrEPiQReiwOk3PU= 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=d4A1OK5+; arc=fail smtp.client-ip=192.198.163.17 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="d4A1OK5+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1745346018; x=1776882018; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=ktnqDeTbJKD9+UQVxGcgPHmHm/rRYJvwr3sT9xCVLMY=; b=d4A1OK5+rD/XmwHajZpag3ymvbBtphbeOW0aW/SW+tU9rENkE6Pd3K1S hOaqGlU4FoCqbQSiqxOChsOblWrZuaLbKv0AjdG/cEJMa05AeTjtH8Q+/ 5VA8vhJtCL6hYD9odNKrHz9Y3vu1FRVE1zBgN42B+CNJzfbGQxm/v9skv xRLgIDAw+7tCQitlesV4pwqL6SM00Ga6Z20hEZh5+de4iJpcpdcXsiIRO auDoVEVhd2QONsumIpsu8zhTcy1/xVSou+Sv+EHSJin7y4fnRiVwaeMay 9zYce8OodhCPk2ahUCQkwGm/S7+A2yFpAG+Wz7JOz+Z/GnYvHYiuT6IKR A==; X-CSE-ConnectionGUID: Mm3d9C3xSUW/hL4v6cqRig== X-CSE-MsgGUID: Zb3DXuKaRYC8YlDUBU2UXA== X-IronPort-AV: E=McAfee;i="6700,10204,11411"; a="46801191" X-IronPort-AV: E=Sophos;i="6.15,231,1739865600"; d="scan'208";a="46801191" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Apr 2025 11:20:15 -0700 X-CSE-ConnectionGUID: 7b1DhfVBTlqTpELtxsGjtQ== X-CSE-MsgGUID: eKJD6W5LQzuNYswV+Tkm1Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,231,1739865600"; d="scan'208";a="155297146" Received: from orsmsx901.amr.corp.intel.com ([10.22.229.23]) by fmviesa002.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Apr 2025 11:20:15 -0700 Received: from ORSMSX901.amr.corp.intel.com (10.22.229.23) by ORSMSX901.amr.corp.intel.com (10.22.229.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.14; Tue, 22 Apr 2025 11:20:14 -0700 Received: from ORSEDG602.ED.cps.intel.com (10.7.248.7) by ORSMSX901.amr.corp.intel.com (10.22.229.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.14 via Frontend Transport; Tue, 22 Apr 2025 11:20:14 -0700 Received: from NAM04-MW2-obe.outbound.protection.outlook.com (104.47.73.174) 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 15.1.2507.44; Tue, 22 Apr 2025 11:20:12 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=YlLNMHu1d4Fjq2U5f8I3zUCyQ7ILsdk2kEWwhrKNesyTZjb74UqRDQPhkQzQmU51D4bP+8+uA253XsDWTRWz7bsQtbgO91IU6vaTI98NreXgC9dbgH0WrMQ8IxPDo9mS+li6CBry5lbQq0n5l2Pf4kjiOb9DOLLOqYvWBB+++4Br3IfsGhS8JmNMoQdiG2uDIh4+9UB92iGgEJb8YKzTmmAF0ri8WpXpF8bYn+la7XDzg387u7Ie8GlA3YMZJ+IMIHE/yOan2kYwfZDrw+V9sQ7ZBImoMFcW7LmcsI4l9VUW17O3pRFDzMHc1NG7FHjeRaqToe63YKivQE6qOUYCSg== 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=XfeAEdtlEAh6L4zm8asW3SlbQWsfDXtJTDthh9hYff4=; b=MnF8SXVPgk6+R7/juVdaDTS53uhinlo9qWJ2/cT0TgmddpKty/gEn5xpzZR4KlRtGnbbVMRXCb8JSIWKMhBP9kdu7d2tplRx3byZRInYG5Twi+Ev78jGmVrikXSrkld8ccRqf4Ef8PFjfgbUsrasjruQ59W5nzWPZ7FiHKXRAVinHBHjzy8sQvCze88R05S/cSh77uUwaKhEE/N9Dt2PEGq1d/I2f4IeZjuWKs+9zvFAMcBbkfRnFgr93c+K7jj6SB0IgVNBHRja02xn0C6GTB3IVyYUhRQ/M9leWx6lJELOHmtDtYfKQm9XA5V06M7ZmnAS6O8CcJaBm5dAqd1ZSw== 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 PH7PR11MB5820.namprd11.prod.outlook.com (2603:10b6:510:133::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8655.35; Tue, 22 Apr 2025 18:20:10 +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 15.20.8655.024; Tue, 22 Apr 2025 18:20:10 +0000 Message-ID: <79a0eea8-e08f-46c7-bfc2-135bcd90dd87@intel.com> Date: Tue, 22 Apr 2025 11:20:08 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 11/26] fs/resctrl: Add support for additional monitor event display formats To: "Luck, Tony" CC: Fenghua Yu , Maciej Wieczor-Retman , Peter Newman , James Morse , Babu Moger , "Drew Fustini" , Dave Martin , "Anil Keshavamurthy" , , References: <20250407234032.241215-1-tony.luck@intel.com> <20250407234032.241215-12-tony.luck@intel.com> <4c8da281-fb6a-423a-bf8f-56c9ee45514f@intel.com> Content-Language: en-US From: Reinette Chatre In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW4PR04CA0287.namprd04.prod.outlook.com (2603:10b6:303:89::22) 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_|PH7PR11MB5820:EE_ X-MS-Office365-Filtering-Correlation-Id: 3de73631-8492-40ee-3dd1-08dd81ca514f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|1800799024|366016; X-Microsoft-Antispam-Message-Info: =?utf-8?B?L1l6UVM0QkJ2NU1HWnJaSVJqbEdCdWlBSUh3bmp1c2dmakhwRGN6djNuamdX?= =?utf-8?B?NllnVW9JZDNFUkdYQ0JUb2xBaEVNZXlEMWpjWEpTR0FmVEttNFkweXkxN3Z2?= =?utf-8?B?cXpJNmlKM3hmNFBoUEpiRVV4YUZMdGtMQjVKd2RvaUI0NUE0SldLQ1RqOEV5?= =?utf-8?B?eEE5U2EydUdXcHYzSnR0RDFHc25hSkZrdGtsWTdnUmduQmZjcnJwbjg1MGIy?= =?utf-8?B?Qy9NYTZYVlFlUWpPSUY3U2FRYWdjZHBGd0J4L2xwNDNQUEJEbVF1ais5RjN1?= =?utf-8?B?Vi80b3M0ZW5HTHEwTTFWa1JZRjJCbGFCZ0hCVjAwcUsyZjFMVXI3b3lyd3V2?= =?utf-8?B?RUpLQ0NqRG9FOHE5cGdJeUV4ZnBBRDRNNCtud0lNeGNrR2Z1N2NUTHV6R3lS?= =?utf-8?B?ZnN2RE9BbXY1aXZ3M0RMeTNTZzYzR21qT0RZVm0wUjk2a2xJeGNHRmhWZXRP?= =?utf-8?B?bDI0TmRIbTk5ZE9JRWd3bnhnNTZGUEM3UjdJSkdYSDBBczZiZ293OUxEQ1h2?= =?utf-8?B?Rkg5bjhGNTdBT1RNVXZjdHNRUGQya0xRbGg3Z2ZQZVhmc0NSVnBxN1ZqN3h3?= =?utf-8?B?VVFucTQ5OXc3bTFhQTh3YkZUZUhRWlJIQllDVisvS3FBaDc3WlB4YXRCbUNn?= =?utf-8?B?amc4Y0FFRll3NjZ4ZlRIOWNNMmtNNzg2bG1SNElWTitXNkxGYS9iaGIxclFD?= =?utf-8?B?RDVBb2l0Mm1jRlIzRzZ6VWVmSFl4RzhkbnVDVjR0V0g1c2tzeGlUSVMxREN6?= =?utf-8?B?c2hZUnQrd0U1NGxDekFSeWw3VDIwa2p0NGd1a2RsMDM4Z0ZPbTlXQ3FxSmhD?= =?utf-8?B?Rnp1VFJkYzN5N1pRVkk0VXN0dW5MSTNYWU1JZ21rc29uNmwyT3FBZ25tbDBB?= =?utf-8?B?KzlYa3lSNkVDMkg3S3JhQWY3d3k5Zy95eWVJVG10ZEZiVHlaNU9KS2hhVlFW?= =?utf-8?B?SnlPWTQ4MEoxNDJUZ1Rwais4ZWdvdmlrL0FQSnNCTmdYcEJxTnRubU1VUy9x?= =?utf-8?B?TFk4aUdHUnhaWDFPd3hPYzRjWjNtTDh6SVR3dlNKZjhBMWFRUjhJcnFRQ25n?= =?utf-8?B?eDJpdnloR1NOck5mTHRnNUY0UW1BMmQ3RE5XeWt1MzkyYm0wLzI0aHZmd0RC?= =?utf-8?B?T1JpL2tXS0xWbWtTa0l6dlRCR2ZVRGRZaDh5SXZsN1YwbVpWNmcxd3gxTzR4?= =?utf-8?B?L3hCYURYSWg5cnhlMnlBM1J6aFpLT3U5RFZHUWJORUpxRmVWeFFSaXAwbTk1?= =?utf-8?B?bHJkQUVGL0RqZ1NQUWhaSEJGalV3UE1FRXRqTlp4SlI4S3g0TGhxRjdacGd1?= =?utf-8?B?WWovTk5XRHRyN0lCZ0VtL1FNMTBPbnordFhHUkl0anROV1BJRWF0VlR3SFdj?= =?utf-8?B?UjYvSU1xSlpkWENlQTVncUt0RW5BN2gzeko4NGVXalZLajQ1YjZOT1h1ZHFY?= =?utf-8?B?dlIrVU5CWEwrNFowcC96MkdIdlVrK1JmczFDNkxkZDNncEtGZm9SWlY3clRK?= =?utf-8?B?SXYySW1zakt4SXB6QlJ4RGxBS2M2alJ3bUZycWZCclZ4dWdjcGZ2SFl3Vyto?= =?utf-8?B?YXBIWGNJUTN0eTdoVGJYbjRvTGZZVW1lcjV0blVPSTVXNDB3MW1RaTlNUkVH?= =?utf-8?B?K0QyL1BTSG5UYTZYVlNQZys2VEd0dFBHcEkwM1B1TFN4SjAxbk1zNjJiZWlZ?= =?utf-8?B?SW9zNGFwcExKUU12RmlsV3JNVE41MWRlZzV6aHYvUVpySzk1Y0ZPaTV6elRF?= =?utf-8?B?bk94SEFkc0R5c0M2RVFwSEZ3VlpTY3ZITXJzSDhuRWZLZmZneGhSdHl2R09n?= =?utf-8?B?VXFRL2V2VGxNNlRya1BmS055cEIrYU9COXpqNjlTeUZiSnpkcTd1NGxpcDJX?= =?utf-8?B?TWp3dkMwZFBVK2xIbGJIeGNmUW9TeDQzbTVsb0ZGMVVyWHZheldQVnZJL1pK?= =?utf-8?Q?qs/sybpcSfk=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)(376014)(1800799024)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?aE1yUkVFYUxDRGhOcjlKS2kvWlI5eVRLS0FrQ1dlRkU5bHhLUWUxVnRqQU9X?= =?utf-8?B?RFNCM1NCaU8xRkVqNG5CYlBEUWVFOHI2QkRHb3pCMWttUVlzZVpwOWlKOFAy?= =?utf-8?B?a3dNT1U0ZFBUeUNwcmtiTy85OExDdjcySWRZZjdSYVlsUnd4S0FqdkorREI1?= =?utf-8?B?Z1I5MzdscHR6SVJEV2RFWFcybEl1OTJ1R1RkcmtjSWNyU1VXSGZncnRXSEVJ?= =?utf-8?B?bzI2VUEzMDZ6bllxdDVrbklOL0tKVmp4VmRsN0UraHRuNzZDZEpzc2RIdWRl?= =?utf-8?B?OUZYYkcvQkJ0NFJlZ1h1TW5TL3lXbUtBU3BBQk1kd0prNGNuNWlWTnBzeE1D?= =?utf-8?B?Z3ljVTJOcnJHYjNWcHcyRW1LTVg1L1pMblo4ZDFvTERCa1VYeUVpZlhNT1kr?= =?utf-8?B?L0VDMm42S2RLRXNoNURpbTdaYk5PY0QyTVZXWTFUVk9jaDVlRlpEVnVyUzJ6?= =?utf-8?B?anhnYmFLQXNGRE1mc0tWMlREUjAyTStTaDI0bjFuQm1reTFSQWxZSDlRMjY4?= =?utf-8?B?aWNvaGtPSUZlVnE3dkkyWk9qdnljbXFvVzhDdnlQdi90Q0dtcjErQzhhUWxM?= =?utf-8?B?WkVWM0RpYzhDcjUrK2pzSkVFUDZ6QmwwTG9TVXFUTXltMU1HVk1YQklLb2F4?= =?utf-8?B?Qmdsa3FXWll3Z0JDR29tdjNPYUNVcDAzUzNkYWUyRUJXTnVmYitzV0hPNjNZ?= =?utf-8?B?dzRTenlIZXd6dkNCaWxJc1dnZndQMWR3bzQ0T3ZaODVBS2pORFlHTGttVkdC?= =?utf-8?B?TStMMFUvbUR6ZmRENHpjcWFpRkV4WXRNZE95cUp4VThNU3p4cDhFWjJQRTcv?= =?utf-8?B?QjQxRGVwK3NacGdsMVFWSCtoeWlhWCtyVzF5VzFySEgvZkRMcXRCeWxYTXp2?= =?utf-8?B?MUc3ZUZtMnc4eGpjSXpPU1QxUHBDaEp2Z0ZsVi9QSktNTE1nOENzQ1A0dXdu?= =?utf-8?B?aUNnWTk0eDB6MGE0eFlYem1pQW9MZFJDbUREeDFTalo3WFpxdE1nZUw2NEEw?= =?utf-8?B?Q3oxRFBsakxFWHBPNXVxVzB5bndoQWprelpGdmZYQTZsQzVpSjl1ZnJkQU5V?= =?utf-8?B?SUNkbTdYZHBPSGowdkNoWXBNdjZDemt3QS9LK1pDWENMV1ZFMjhhb1VHazd4?= =?utf-8?B?dXpzVU1BVXNVODIvbmRlS1FpY2hZcFlXVTB6Mk1UMGFkYkxOY3RUQjFseUw4?= =?utf-8?B?cjF1OEU2T1d2L09EeGlFWmFWTnZKR1VLUjBTYUpkbEtjaXhoWmVCOGJYdkho?= =?utf-8?B?OWZkSXlJQ3NpdUxmazRndHRyQkVORUVVMC9HVHYvbG44WmVER3R2aXVrREd4?= =?utf-8?B?bTQxM0ZZTisvL0NzZjQ4OFhnRjFUMjBIejFmV1AyZ3dSMDVDOWVSQ1VDMTNH?= =?utf-8?B?Y1ZFM1hDRDJoNXZUT3MvSHRRYnZWbDJQVFk0cm91SFBORlhhNFVjVVRJbHBa?= =?utf-8?B?SzVyQ3RmbDNJcW9VbldxeUdXVHh5NTVOc05wTTFhZ2pncjFxRzZtSnhNWkVC?= =?utf-8?B?Ly84RCsyblhTRkxIZjJHSDVKR2U0WmY4QS9XcmYvQWhYVVJ4TGVzOVFWbFFl?= =?utf-8?B?UERsSm1LQkJqTHcwSEp1VVZPWTV6RDdwRk5vNDB1YmxQNTRmNXRpMVFXRDZh?= =?utf-8?B?dEx2WU9Edk5uS1dVaG5YVWVXN1B3aG80YTlicVpyZm1VVWFIbFlONktxUWM2?= =?utf-8?B?N0JBaUxjYU13RHhWeXk2V1k2NGg5eGxnSUdGek93WmFtRFN4Yks4UWttdG93?= =?utf-8?B?OFZrZitRbnpNbnUrbUY5ZmRJWmM2a1JRVDYvSGdSaytHR3dTa3Z1VWhmajJ2?= =?utf-8?B?Y3VDd1ZwcHdJZElBSzdIVEtQNXhuNFUya0o0SlNSYTFieXRETkNSaWh6alhM?= =?utf-8?B?SVdlVWllby9vRnRKeDhYQlcrbGNQS3hLdmpCVmVmbXkxTjMwcDRodnhNWTBx?= =?utf-8?B?L3B4a1N2WGVuWGFwcThSd1dodXZreHpTT0REVCtSamIvSDBURnpUU0ZkekZ5?= =?utf-8?B?Q2dkZGo1UDdySlJEMEkzT2x4TVlpbmVrTnRhTGliQUdOUDRqa21iUFNlWld2?= =?utf-8?B?OVFxdnk3bE14TlBtNjI0WHVUTWJvRG11b0JJMi9ockpBVzU1bXJMVEk0d3Rr?= =?utf-8?B?eXpHdGdibkJUNC9zbVhiRDhmR2lzLzN4WGQxMVBUbHgwTnlldGRmZDArWk9q?= =?utf-8?B?YXc9PQ==?= X-MS-Exchange-CrossTenant-Network-Message-Id: 3de73631-8492-40ee-3dd1-08dd81ca514f X-MS-Exchange-CrossTenant-AuthSource: SJ2PR11MB7573.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Apr 2025 18:20:10.6291 (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: JE4vHBj0cWVJNrFxpqkivS9hAGDUg9wXJLbgkjtYbI7S6plSy7SlwPvS9n0X7r5hmNhrcC56MRw8yDbRj2CMq4zHuW55ClFzSKbKQJg1mio= X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR11MB5820 X-OriginatorOrg: intel.com Hi Tony, On 4/21/25 12:34 PM, Luck, Tony wrote: > On Fri, Apr 18, 2025 at 04:02:08PM -0700, Reinette Chatre wrote: >>> + case EVT_TYPE_U46_18: >>> + frac = val & FRAC_MASK; >>> + frac = frac * 1000000; >>> + frac += 1ul << (NUM_FRAC_BITS - 1); >> >> Could you please help me understand why above line is needed? Seems like >> shift below will just undo it? >> >>> + frac >>= NUM_FRAC_BITS; >>> + seq_printf(m, "%llu.%06llu\n", val >> NUM_FRAC_BITS, frac); >>> + break; >>> + } > > The extra addtion is to round the value to nearest decimal supported > value. > > E.g. take the case where val == 1 This is a 1 in the 18th binary > place, so the precise decimal representation is: > > 1 / 2^18 = 0.000003814697265625 > > rounding to six decimal places should give: 0.000004 > > If you run the above code without the small addition you get: > > frac = val & FRAC_MASK; // frac == 1 > frac = frac * 1000000; // frac == 1000000 > frac >>= NUM_FRAC_BITS; // frac == 3 > > So the output with be the truncated, not rounded, 0.000003 > > The addition will have a "carry bit" in to the upper bits. > That isn't lost when shifting right. The value added is > as if there was a "1" in the 19th binary place. > Thank you very much. Reinette