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client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by SJ5PEPF0000020A.mail.protection.outlook.com (10.167.244.43) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.382.8 via Frontend Transport; Thu, 3 Sep 2026 16:02:57 +0000 Received: from satlexmb07.amd.com (10.181.42.216) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.46; Thu, 3 Sep 2026 11:02:57 -0500 Received: from [192.168.0.101] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server id 15.2.2562.46 via Frontend Transport; Thu, 3 Sep 2026 11:02:55 -0500 Message-ID: <0e5e1fd0-0a46-4c1c-a391-5c245d903834@amd.com> Date: Thu, 3 Sep 2026 21:32:49 +0530 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [DISCUSSION] Three problems behind broken "perf --call-graph dwarf" on AMD: IP and stack dump mismatch, libdw fails on lld's layout, and the unwinder fallback never runs To: "Mi, Dapeng" , Namhyung Kim CC: Gennady Kupava , , Ravi Bangoria References: <27d79477-c469-413b-95bd-c6c1f8a40f55@amd.com> <7b4cba95-dacc-4cf1-953f-c59e06e693d0@amd.com> Content-Language: en-US From: Ravi Bangoria In-Reply-To: Content-Type: text/plain; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: nvTttgf9d3nB1ivY0egXlYiYPAm79i3M0g79DxPbRgxkPX4xek5Nq3REPYnVe+5GzodKcKf+bYebsd0Z10DLAHZDFJEbOOAxiHE4rqFy6RpRQ3O4+QSOqi5/3cE0fFgVucVGa0NXdt333kmzYLxMru3bXtwLD8T7oWUPp5SJRKk0I5l0wBpvKkmDCyjLCsxoitNoVJIld6pLQ/Ilu7oULqpMdeh5K8tSL1KJ9Q9rLqsAdNrNSr1y3oUaByXz6Pqz0wB4Y4Cmp4Hz7JLLcBlQcGyUwAbCt8N1QJaAOMZZVgU0X9/lKLbM23RcjSgZKT1FHBgMB3odHG9oWDxap9r3SkZR4KYy7i0yknkpi0xfxcLKq8Km0Uiza4Mn18z13GmAQo8gc1JWPErqeaetga6jcNMSPHfdqmjUrBOFXNBhaKMsj2nmwLnXedfqN1WcUI+y X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Sep 2026 16:02:57.6769 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: a7d2d4f7-81e9-4269-f9dc-08df09d4d264 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=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SJ5PEPF0000020A.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB8191 > Suppose we need to follow below 2 rules to ensure the correct call-chain > unwinding and register snapshot consistency. > > 1. All registers including IP should come from either PEBS or PMI, must not > be mixed. This ensures to get an consistent registers snapshot. > > 2. Either SAMPLE_CALLCHAIN or SAMPLE_STACK_USER is required, the PMI > registers snapshot must be used. This proves the correct DWARF unwinding. > > How's your idea? Looks good. Mind sending the patch? Thanks, Ravi