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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?4a96XqKmI/0vjTHik1aPKK5DsVMikmUfZfG6axXTn60X5gaoHzbKDaydB7fl?= =?us-ascii?Q?1j2UHebAYSCwdu4+7DBHZ0Mj7yKJH9MUAWf82zJuZGedPMU8S01eZ8vSJMlY?= =?us-ascii?Q?0p1SvqN5E2K6tHMvCoCisPLXPeovRFpmJXbuk6nbAL8k5+9mU9YRuo/uRZ+T?= =?us-ascii?Q?lzohtl8a6wzGlQ/dDDiBk8mxRj4o5YC4UBPKZGVNSv15keEONCBdz5/Kpwox?= =?us-ascii?Q?iEFFZNaUgMBOJwO/dN+jmQNwISk0UXQdyGE9ECuCuVZJaENOozIUEvgO0Lvh?= =?us-ascii?Q?F/29uCKe/okfSTRjYrAFKedtmapDF1pmAysUgD2G7I1eoj0sVuWVa37e9WjK?= =?us-ascii?Q?nf2ge3HB/4GPfupSJWZ+IrWLM2uEF+NV2o92de0KmGn4O4JBcVw2DllpR4Gf?= =?us-ascii?Q?oKd0csL0r3xUaZJeL0L8sjZP7UqhOdKIQnWrrOlEgjwWTpbR9eb7gZMzxDdc?= =?us-ascii?Q?CKopHGgQfd5zdIHR5ay3+GwT4sU8NUsQ2hvG5ePUVJ9HFIIGds8RITDVLcIq?= =?us-ascii?Q?q4mCRKwfQtLLqiS7L7uaBFuhdhO+am/Gf2p/u8kOPYi61uIO2/5Ts1JN+wnF?= =?us-ascii?Q?9YxnXRwu+pEW7dOXyIBfa2U8RfZaVdzW4baFxF8FBkXA6Va2PsyvCs8m4g9G?= =?us-ascii?Q?qusIbvRJGCMRgpuMjJHaLsdh09q9CqF0Tssh1rkkCfRA8d1+pNncM1WQWkf/?= =?us-ascii?Q?n7EVcVnZvHEsjXIP5Kwuy59CDgdb8q3OIPIfe22pDBm6k+0jPe+TvwRBewLY?= =?us-ascii?Q?cR5DJtJT23LrgB4gmguRN+6Ky67+FeA/ks3SyGMnsQs7WgUGaOwogSKU+Qpg?= =?us-ascii?Q?0AZiw8DP5lKDvnnQsBO3qagNNIfh1Kc9O+GJg5ZTd3Np0CCmQsaMtyvVH7Mw?= =?us-ascii?Q?4YUklr1xOMtfK721UHeHKL6WKh/i5p3ny7wL/gQjyCaUx/oIYoyvYl8f+iJ9?= =?us-ascii?Q?AgK+4g12Y9MEuewt6LBZzIRbQdpqncT1RqPLCxKjw9Vl5aZhCHDfuEKCObYs?= =?us-ascii?Q?j3V1zj5K7vYiye5NZxJ7kXctJtmwvf7k8OtEPPEYkWD0TZQ61ogcLOjlIOV+?= =?us-ascii?Q?0TuRcJQp/dIg+B7cbqLli7SCtsJCINi6ASLzBnd13a3jjbZaHTwKiozVSMuR?= =?us-ascii?Q?JTrraLMi9nLDplpziLPOMEvQ1cq4VSUbJjJDD4u2YFIwCgy9DTZRd0uSykNG?= =?us-ascii?Q?N/JBcpwlwNEwc4W5plg+wQnr+T7691BNh/XQgd8OaRhWOuoE+/Lo0nI4ab2m?= =?us-ascii?Q?gdYGj5UoEu4Ni2kTg4rJsiyX4OZF9fWZBVb2GdQdvfDeTeGpTlDix+WnuWUb?= =?us-ascii?Q?k7R/PFbt4sPDF4ZfTdQemosxQwf2G0V73KsrbVWm2XuFyGdRGJWT4RH9Yw6O?= =?us-ascii?Q?AbJQmPD+x4Bn/4I2Byr+PSWg6wgaEDbuiwsMhgaFiPIQHerrkDCMwgz1/pl/?= =?us-ascii?Q?1k0u6KFijDO8T4aj8JkzcydOtV5hGJzy9QLyMBNOkWhymmTokBR0oaHVGV51?= =?us-ascii?Q?LsT90sNB62KgjE8/3IFdUcozVIv/hQPZBqZ4C4K5pwnj5nNdiG5U+tMw1rw+?= =?us-ascii?Q?mFO3+plJMn7k8af8OdpSrpN0Mx1kwNbztBwjQwmt?= X-MS-Exchange-CrossTenant-Network-Message-Id: f0b08bef-f427-46a1-262a-08dcacb9467f X-MS-Exchange-CrossTenant-AuthSource: DM4PR11MB6020.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Jul 2024 14:51:33.2542 (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: Wd1cLtsOv6OI5RWhLH2GupJPBOH5swvt5p0wjO33POsnLO1WmZARtFany/UycxFRqBw+dTP6xXjaYggtaBCBsA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR11MB5893 X-OriginatorOrg: intel.com On 2024-07-25 at 15:18:50 +0100, Hongyan Xia wrote: > On 25/07/2024 15:00, Chen Yu wrote: > > Hi Hongyan, > > > > On 2024-07-25 at 14:16:30 +0100, Hongyan Xia wrote: > > > On 25/07/2024 12:42, Chen Yu wrote: > > > > commit 97450eb90965 ("sched/pelt: Remove shift of thermal clock") > > > > removed the decay_shift for hw_pressure. While looking at a related > > > > bug report, it is found that this commit uses the sched_clock_task() > > > > in sched_tick() while replaces the sched_clock_task() with rq_clock_pelt() > > > > in __update_blocked_others(). This could bring inconsistence. One possible > > > > scenario I can think of is in ___update_load_sum(): > > > > > > > > u64 delta = now - sa->last_update_time > > > > > > > > 'now' could be calculated by rq_clock_pelt() from > > > > __update_blocked_others(), and last_update_time was calculated by > > > > rq_clock_task() previously from sched_tick(). Usually the former chases > > > > after the latter, it cause a very large 'delta' and brings unexpected > > > > behavior. Although this should not impact x86 platform in the bug report, > > > > it should be fixed for other platforms. > > > > > > I agree with this patch but I'm a bit confused here. May I know what you > > > mean by 'should not impact x86 platform in the bug report'? But it closes a > > > bug report on qemu x86_64, so it does have an impact? > > > > > > > It should not have any impact on x86_64. I added the bug link here because I checked > > the code while looking at that report. But that report might be false positve, > > or at least not caused by this logic introduced by this commit, because > > CONFIG_SCHED_HW_PRESSURE was not even set in the kernel config[1]. Maybe I should > > remove the 'reported-by' and 'closes' tags? > > > > [1] https://download.01.org/0day-ci/archive/20240709/202407091527.bb0be229-lkp@intel.com/config-6.9.0-rc1-00051-g97450eb90965 > > > > Yeah, it might be a good idea to remove the link to avoid confusion, like > you said HW pressure is not compiled in. > OK, will do and send a new version. > Even if there is pressure support, before your patch the big 'delta' should > only result in a HW pressure value that decays more than it should, and > should not be able to block tasks like in that bug report, so it's very > likely that it's unrelated. Yes, for x86_64, the rq->avg_hw.load_avg is even 0 as it does not have a chance to get accumulated. thanks, Chenyu