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Peter Anvin" , "Peter Zijlstra (Intel)" , "Xin Li (Intel)" , Pawan Gupta , Tom Lendacky , , , Mario Limonciello , "Gautham R. Shenoy" , Babu Moger , Suravee Suthikulpanit , Naveen N Rao References: <20250825075732.10694-1-kprateek.nayak@amd.com> <20250825084950.GAaKwjrvrmXZStqrji@fat_crate.local> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20250825084950.GAaKwjrvrmXZStqrji@fat_crate.local> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN2PEPF00004FBC:EE_|DS7PR12MB8273:EE_ X-MS-Office365-Filtering-Correlation-Id: 2860479a-b9a1-4563-e673-08dde3b64058 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|1800799024|7416014|376014|36860700013; X-Microsoft-Antispam-Message-Info: =?utf-8?B?Mk40SlN0eVFJRU5IRlE2d0ZZK1U2UHEzVEF0R1FTNmN5VmJ2TUZvWUlXK1Rh?= =?utf-8?B?RllYNjgvYjkrYWtpR3lUSHMxaGtnZ2U2VHY1Z0pzaEhhditQc291dEdFand2?= =?utf-8?B?YVVwNkdaR1J2dWdtYXN1bnJ5K1RsT3pPZllOOSsyVHM4UFJlaFpYS0lCK0lQ?= =?utf-8?B?dEtqd3RLMkNWOC9LU3pkVjB3V3cwNnZ2aHN5NWlTdk54TDR5MVpIbjFwUDB3?= =?utf-8?B?bW1zZ2xicFE4M0N2K0ZLNUxza0RCNjRZN2RUL3hlZytaUFN2MWd0SEZwRndS?= =?utf-8?B?MWlRSGhFKzlXZ3hwbmRYQXVaTXQ0ZEpIU3NNL1BzT2s4MzhQczRxUEtRYWxx?= =?utf-8?B?akh1U1l0VVZPVVhYMEkrb2c5NVZwZDNua3J0TXdNaDNFd01EekNnVnhRZTdN?= =?utf-8?B?UzNkeWVpNVhvRTVTZ1JDaGoyK3VxWEx6VEtxTVlCRExHWDJwUzlmUDhabXN0?= =?utf-8?B?bmJMNDIvNEYwdzN4KzUzZktpYVc4Zysxb1BQNVJQUXA1cFNWVUtMdVdlcVU1?= =?utf-8?B?TmhrY2o3UFYwUDk4d1ZXcFZVTjl1NXZHK1pOYVZCT1dQVlFHT0VDTUZZTy9a?= =?utf-8?B?RmZZWG1nZEk2eTN3SWJKUnpsRGgvMWRGejJJck03ekZPTjVRUVBTM01SV3Zp?= =?utf-8?B?alphWkExZTQwWC9GUnFPZitPanJLN0lycWUvSjBXKzM4N1RDbGFSVzhHMGVM?= =?utf-8?B?SnhXbG9UZ2hnaTlqWEZJREJWaHNZKzN6U25ZUHY3Q0xKdmg3dmtVY2Juajlp?= =?utf-8?B?VE1teXRWQkJqczBsNDBCZEJ1VVhVVmpXajFRc0V2YXcxRUErRytjNVlaNjlh?= =?utf-8?B?RFlxeExHdkVRQVdDYko4MURxUWxUNkRXRXU4RGVQVU1xUDJ6T0lXT0RqS3N1?= =?utf-8?B?Mm1aTmRpYXFMMWpzYWxCVE9ocjFsZUl3czBXT0RxTWVvdlRNTE5hYitkcTFj?= =?utf-8?B?ekdjeWFRM3ZveWhOZnp5MDVma0R2VlEyc3NyU1hJR3hUam9JM1Bnd3RWYitK?= =?utf-8?B?d2RFWjZ3L1MyVzJKUzhuZFovQ2FOVUNUZ1FvQkJub0kyek1ySFFDRUdZUWtY?= =?utf-8?B?UytReUN3K0w1TXFqeHgyRGxhdU5ZbTZZVUNZVm5Gb3J2SkVUWGNaeUlEUGR4?= =?utf-8?B?cUZ3T0hPdWZZUlhTSkJ1RFNYWVMyelJGODdCenk0eWxNUjJ4b0I1Y3JwdWpX?= =?utf-8?B?b0t5VHVDcjNiajFEa1d4dkIzbHRqeWNkdXNIcER2Z3pyaHpZdkwrejk4Rjli?= =?utf-8?B?NHhyeUV4clFtZi9YOXhFamRaMm1RdkZuN0hBUkNLV0lrZjV6M1NsU29CZE1J?= =?utf-8?B?SkVDaFYzOXJwR1VUcGYxWDR1S3ZpN1lHTWFWRTkyeGluUy9VQXNEcXFORllr?= =?utf-8?B?L3hpY1NIcHpTOXkzdjJlM2lkVUhFL3loM3NTVFU4TTRESzY1UE5MRlV5bThV?= =?utf-8?B?S1RoU2xsQ0FtM3lZbk9DNmI5bzdzbXNsS01Qby9vbmZoQzBPanE5Y3ErbEIv?= =?utf-8?B?VmhPNkpnUkFKRHV4ajkwMnBoZU1DOTlTa05RQlpkeG9peGVNQVVlL2RMSmdZ?= =?utf-8?B?TVY3dEVUMzhhV2VBSEJ2TWZaekpCUUdjdElnTjJCUXFueGVTSUI3eGtvLzNl?= =?utf-8?B?L1JCeHI2SzJjYzE1Wm1SdVZaYkxJRDdacnZSNnNXZGNFUmtHWWVDQ0FRUGkv?= =?utf-8?B?aUN5SDUzYnlZQTNERWFOUmVEN3l3ZVpxYkZSaTVFVmp5aG5oOXUzUlRKVnFE?= =?utf-8?B?ZFhScEF1cTZZbUxvS3BrbWUwMWNrVTFjWk9vakYzMUlEMWN0a1dCS1NRU3pX?= =?utf-8?B?ckp0UUF0dEZWUENHVk1Qd3BGc2I0MUhpRWF4WWdtSmMweXZUQXVnVXU4RHZq?= =?utf-8?B?ckIrZ3hyNlFNVHl3YXBGMUxjRzdBZUc0OEcxS3NrdFZ6TEFTTGlRbjlsVTd1?= =?utf-8?B?bnhjUWVBdy8rcjBZNkIrNlJRRjJSZzFnS3o4Q3RPNlVzSXROeGl5bW5ybkh2?= =?utf-8?B?RlJBcmF2VHRwQ1VGa2dsWm9vNWpiY0lGYjVHRndKVVRkL1MreHhaSkpYR0w0?= =?utf-8?Q?L29U5U?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(1800799024)(7416014)(376014)(36860700013);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Aug 2025 09:03:25.9177 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 2860479a-b9a1-4563-e673-08dde3b64058 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN2PEPF00004FBC.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR12MB8273 Hello Boris, On 8/25/2025 2:19 PM, Borislav Petkov wrote: > On Mon, Aug 25, 2025 at 07:57:28AM +0000, K Prateek Nayak wrote: >> This led us down a rabbit hole of XTOPOLOGY vs TOPOEXT support, preferred > > So in order to save people the rabbit hole wandering each time they (or we) > have to undertake, I think we should document what the whole logic and > precedences are wrt CPUID leafs and topology. What should be done where and so > on. > > And those commit messages have a lot of text which explains that and I think > it would be worth the effort to start holding it down here > Documentation/arch/x86/topology.rst > > No long texts, no big explanations - just the plain facts and what the current > strategy is wrt to which CPUID leafs we parse for what in what order and so > on. > > You could start the AMD side, it doesn't have to be exhaustive - just the > facts from this rabbit hole trip. > > And then we'll keep extending it and filling out the details so that it is > right there written down in one place. > > Makes sense? Ack. I'll start working on it. -- Thanks and Regards, Prateek