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Shenoy" To: K Prateek Nayak Cc: Mario Limonciello , "Rafael J . Wysocki" , Viresh Kumar , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Jonathan Corbet , Shuah Khan Subject: Re: [PATCH 9/9] Documentation/amd-pstate: Add documentation for amd_pstate_floor_{freq,count} Message-ID: References: <20260306095753.17155-1-gautham.shenoy@amd.com> <20260306095753.17155-10-gautham.shenoy@amd.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: MA5PR01CA0211.INDPRD01.PROD.OUTLOOK.COM (2603:1096:a01:1b0::12) To DS7PR12MB8252.namprd12.prod.outlook.com (2603:10b6:8:ee::7) 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: DS7PR12MB8252:EE_|SA1PR12MB9248:EE_ X-MS-Office365-Filtering-Correlation-Id: 5897e87b-4bb7-445f-201c-08de7f598fdc X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|366016|56012099003|18002099003|22082099003; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?8ZRo/j5U9YY5M2d7KMTi4e3/QVXjqYLTTqMi6Q8OdeduGU/IajJD7uV+vsCD?= =?us-ascii?Q?fP6fFcDbSErzL2kZOgaxkGrrYCkG+TXgqIfpcx/flCHnkt/tIhO92MVaJh5P?= =?us-ascii?Q?4zQCdRVDnqdZc/CVOQYpWlRf9i7d9nO9+gL784jKFU4CaqQI3jN2P11j+HCq?= =?us-ascii?Q?/ciiy/VxC/aNmYJf1aywHe31Szi1KzzBoAbm5BmsxRKVuslZE327gY81GZMB?= =?us-ascii?Q?RKkjnaFH2DsIxfShvMq9f9DEk3bplnnWU3kJft+oxkERMRP/ph7CnpJgIno4?= =?us-ascii?Q?O3Rk5Ug8FmG0VKakTWSQJD18jPoCmg+O6wPkAjmP1hBx6o7bSEq9BDZP4nGQ?= =?us-ascii?Q?JfpbsFxo6rUEJyFWT/YsM+amud7xZ5Ii/l2hgIhvuhf2BKiJ1x/HGkjguEcz?= =?us-ascii?Q?91+lqHuItVUsU2DdJb3lez+KqaCsYwT8m81fRFltiCgt/DwklsTUtP31rGVs?= =?us-ascii?Q?HaMiHig1KCX2nJohOtAxNTsV+HhFRddcZsa+anY8KULwmAeLhK28e4CUXwlp?= =?us-ascii?Q?IuxSjez9PcqLgxoDE2ecBPgjLGuh6HgDUCEUes/cb1Nvgra7a2n6KpfW9TBc?= =?us-ascii?Q?Xz1mhRPvrSelw51UlZ3LiaLM9QgjgESHDTw2B8Zpfsnh1XZZ3s7IaAjuG5WQ?= =?us-ascii?Q?iN+LJ3kBp7oJDeH0+yo0GfUII3w/81PlzLDq6I1Mo/CEQC54eHPGxMMj4rEP?= =?us-ascii?Q?bNbH7U8Omkf+IpOxPEfWFQh2LLva3pDCuq4tHwVV0bzM35kYqQFT5ZJgr2ot?= =?us-ascii?Q?TM8yuPDdOp2xEZ48lb0+xmvy9BqnQW/WCkjAeft6tRQ5YXP8Hrt3IOBFIaUT?= =?us-ascii?Q?2BPjsuEqm0UIBmEqWPSzTBKOAT0IIe/fIjtJmQmxwTToSCbknzGzmIRNLDxe?= =?us-ascii?Q?82Fp/i9zGIH5gL3A8vb9+IJHnHooBwWixcbvK9q2pj9tJ0RImu9Thp4JUa56?= =?us-ascii?Q?xSyG5IJnm1A6yGMHsOEjCoFBeAhDS34oXE+RaKemeaGZgbT2IHd3i/EWqlZi?= =?us-ascii?Q?tce1UUBvZxQWKlrMr0vxfGmuxxOXBg2smsKP9RBmt/gGsBGx9I3m8B6oQ+Cw?= =?us-ascii?Q?tPI8FFT3F8sPMPINxA1pp0F7gZZuD7OsKdFW0XnaZ7FGbRE/YuFPIkupTmCM?= =?us-ascii?Q?4OhWiZ39C90LPXFW156IdEoGAcsAlRID6qblgNEXcnL67nirdqcYWfrwAdrF?= =?us-ascii?Q?wqowx3lRNXS5iJmRKNYWEfNhAhicjnoNnssmMqBVP6H9Mipp3Z6qCAmy0YWl?= =?us-ascii?Q?nADfUFXw67QfxhaW6uqcjVPJ+slQZTpkXjftONfo9FehFl9l79dZUggmatyU?= =?us-ascii?Q?cOr5Re9dDt3tvODYW+gxPHlrzmHT+GXDFglS8dfWWco8xFQGafJXHPkYChqr?= =?us-ascii?Q?lr/H9M8zBIltBgcFOIunDXTBKCuNCen5VTMmUrRmXdUdC04qQUj2B98Lo6ha?= =?us-ascii?Q?T8s7bXi9jIzzNFqEssKtZmmmqeplkz/1uSFG17vi+A6JWQf6wnZvj2CDOe24?= =?us-ascii?Q?aIZ2/UcGf5+Wq0A4ORNezplXCjroAFb53X6km+SQcwB1e/ncW2NVBUpf+bX/?= =?us-ascii?Q?K4i8nbOBBS047UFMTBLrTsmY6CZXKM6fRDwEYry2l3nj3rZyW0JjWXIkHYUK?= =?us-ascii?Q?ervPkEODcEJxIWjRqGRHHw7JpL9NpXdHNH9p59LchVKGYtUCe1DoGqJdhvja?= =?us-ascii?Q?L5ksX2qxY2fryh18u1sxtrqS4W/ja826HJhp0zfC2wkZlXYfhoaCwkTcnc+X?= =?us-ascii?Q?dQGgKOe34A=3D=3D?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5897e87b-4bb7-445f-201c-08de7f598fdc X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB8252.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Mar 2026 10:32:57.9219 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: wUFj93omEFSKiSVp5cqgom4L+5msVFF2wphqpgswAe5Ur6JUriqcB9g/E5itizklZRwSkT649ybOC3m2CvKgQA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR12MB9248 Hello Prateek, On Tue, Mar 10, 2026 at 09:15:03AM +0530, K Prateek Nayak wrote: > Hello Gautham, > > On 3/6/2026 3:27 PM, Gautham R. Shenoy wrote: > > +``amd_pstate_floor_freq`` > > + > > +The floor frequency associated with each CPU. Userspace can write any > > +value between ``cpuinfo_min_freq`` and ``scaling_max_freq`` into this > > +file. When the system is under power or thermal constraints, the > > +platform firmware will attempt to throttle the CPU frequency to the > > +value specified in ``amd_pstate_floor_freq`` before throttling it > > +further. This allows userspace to specify different floor frequencies > > +to different CPUs. For optimal results, threads of the same core > > +should have the same floor frequency value. This file is only visible > > +on platforms that support the CPPC Performance Priority feature. > > nit. Should we note that the driver caches the closes perf value and the > read of the file will output the corresponding frequency of the perf > level? > > Otherwise, it might come as a surprise to the user that the read of file > returns a value very close to what was written but not exactly equal to > it all the times. > > Or should we just cache the raw frequency value when user modifies it > and keep the perf translation bits opaque to the user? I think it is better to cache the user requested value of amd_pstate_floor_freq in cpudata and report the same when the user reads the sysfs file. I will change this in v2. Thanks for the feedback. > > -- > Thanks and Regards, > Prateek > -- Thanks and Regards gautham.