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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?N+lQ2fkMCfUaGbH6YjMHVqwM/bFW728ROr60a2QGIP7c0FYfzjJLBjBQhYbY?= =?us-ascii?Q?6vtaWoY6FF26gctgdgrmjZZx9y/FMA9gjjWe8rYRtqtgnagH+nMQ/Zsi//07?= =?us-ascii?Q?lVS5XHBEK6JRKUrbZKvC0hZwTtpVlvf3+A4PKn71YB33GrQdp6Mf7Tk0JCXZ?= =?us-ascii?Q?mg5Cs98Pj+zXSTxr9HqfQDpu0ppZ+anpEUpqmA9Erb1eRTY7s5/uDsOj7GCi?= =?us-ascii?Q?F1UBQwQv7NTtQYPfX82Bi99Iym5M936jLJiNkvvFjdVgAHlc3SmyZcXKE1A0?= =?us-ascii?Q?yj9gmSOpbhFwKk6mk2a9UNNA7n0HxJLWBcvh3Wg4NZiwPZRWnmcaeFO0M4zQ?= =?us-ascii?Q?JobXG1uxD/SGGhUcafvrKziE8mxYTEwReabOJVuPgRxTPnm9URufBdc6cGZU?= =?us-ascii?Q?JHI5y111kDqUzCIqKUvXN8TbM90/agn05525IHq92uV2Lp5afGrgkVxwl79C?= =?us-ascii?Q?SfrjI9JGoxP4cHgmMONVaB1gGaTxC9sFrwulkk9O+1zero00tq6tNHcSTErR?= =?us-ascii?Q?erA4vTaNfDkfCeDFYRn9eoilAcpZL5dgiap6AUf4jvRkQoFRsgSQtZxGW9J6?= =?us-ascii?Q?ylBknTrNpmwtbXt7HNG2beWQ22JUpDxQdOO3RT+7vFu+rliCmSOYZHqjWT6N?= =?us-ascii?Q?/CeBxUO6ohZ5mOzG3wq9S5UJtaBdpRG1B+Mdm/Vn5dmA61TQV8UGEBasdejx?= =?us-ascii?Q?JU4vTHoBTWcoJFeRN23IouBiwP9SN7DwHB1GESAmE/q1PXb/EDAAjuk4cIX1?= =?us-ascii?Q?/F97OWXz5V+R7PPhFGrUjfvR9GJXLBmBxRN4XOld6mn2zRsGOeid/qK6iLLL?= =?us-ascii?Q?jqMQkOi9l2+Ajrljk6I5koyW4f1psZagFrLP2ecKrJ2SEbbWvZRrmqeuJe93?= =?us-ascii?Q?B2emQO9dBYD8bm5YvqWkNHDSwaES0qFHtiPVi97SdrcuxcvHA4DVFkBCwqI6?= =?us-ascii?Q?bi72NO3Q6xWWmbA4fDe5RvQ8sw6GMiZwAoMhse29b3HzLIHi851lKMGdRFJ0?= =?us-ascii?Q?SA+jl+J8oI4arAPAXnEEUEJeUmEPMDofWKf3KcdMeIn3JJcTKdkky2RwARQ2?= =?us-ascii?Q?3SDxTp7dGjFs9YOGxgEYHb1wOleh638ak9hf1aEJiBIgwaZCmowgZZ+c2z8o?= =?us-ascii?Q?skUqyrpqqhpln72mpm6YE6Lfsa9afbGTnxP7z7EhZGdrQoVqL622GYBYh0ju?= =?us-ascii?Q?zd2/WysO4t37jELDJ1b96+D9b1j23GDGCmLnXeQZftSR3ZmCKAburUR8fIEr?= =?us-ascii?Q?LEl/Xfi0J479IiLU2GwUlBTeNECGtrOx3xyWsTWIyTznMEE5D72m2oG2GaK3?= =?us-ascii?Q?NWcWgIIr4r6P5Hj5kSsBG8QYH6DdORwtImqyNY/yw3Ot44kYhHj0Z6OIyFsY?= =?us-ascii?Q?LHZ/8l2SACGyy+YEIFctWm5MGG+Oa9VFIIV6mCWL43uHyXJWD8KKCxZ27TsS?= =?us-ascii?Q?CudUn/bnYNSHRCvbujPB1U9YppUmQNpdO9KRsEd5bfPfLrXO6BzEPhM07ITF?= =?us-ascii?Q?x+dWQOfBQrFpluYef4NCmzSbpm4EIGrQWcymSLx0/UVZSR2sS/8fSbSGx+2C?= =?us-ascii?Q?gTTRWVPCLaKkoo/w8jwT2f3aegmzSF6G1uU10OFimvyXstoX4kjYkHZhqTyt?= =?us-ascii?Q?IfHBV9QUa4amnFcd7ZALz86CU9bHUTuC+0HvkZsUpwyAyL7KDdK1ZyD4Vtxx?= =?us-ascii?Q?ryD5NCYc2qVTxy9Fb7f26YaYs3TQK5zjRQn1qBnwdGpCEacCNjaqsO6Od0eK?= =?us-ascii?Q?9TlFkrt//Q=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 7867dd62-2def-4874-07a8-08de8bcd74e6 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Mar 2026 06:52:48.2966 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: avABGiOXv4FfcOcloL1+qqeDWvR02RFSOYaYtfY9OWPShFk2XNOAlR9bFBT2vvSXj45dPgO/K59tTlrJKP+V5g== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA5PPF7F0CA3746 On Thu, Mar 26, 2026 at 04:33:08PM +0000, Christian Loehle wrote: > On 3/26/26 15:02, Andrea Righi wrote: > > This series attempts to improve SD_ASYM_CPUCAPACITY scheduling by > > introducing SMT awareness. > > > > = Problem = > > > > Nominal per-logical-CPU capacity can overstate usable compute when an SMT > > sibling is busy, because the physical core doesn't deliver its full nominal > > capacity. So, several SD_ASYM_CPUCAPACITY paths may pick high capacity CPUs > > that are not actually good destinations. > > > > = Proposed Solution = > > > > This patch set aligns those paths with a simple rule already used > > elsewhere: when SMT is active, prefer fully idle cores and avoid treating > > partially idle SMT siblings as full-capacity targets where that would > > mislead load balance. > > > > Patch set summary: > > > > - [PATCH 1/4] sched/fair: Prefer fully-idle SMT cores in asym-capacity idle selection > > > > Prefer fully-idle SMT cores in asym-capacity idle selection. In the > > wakeup fast path, extend select_idle_capacity() / asym_fits_cpu() so > > idle selection can prefer CPUs on fully idle cores, with a safe fallback. > > > > - [PATCH 2/4] sched/fair: Reject misfit pulls onto busy SMT siblings on asym-capacity > > > > Reject misfit pulls onto busy SMT siblings on SD_ASYM_CPUCAPACITY. > > Provided for consistency with PATCH 1/4. > > > > - [PATCH 3/4] sched/fair: Enable EAS with SMT on SD_ASYM_CPUCAPACITY systems > > > > Enable EAS with SD_ASYM_CPUCAPACITY and SMT. Also provided for > > consistency with PATCH 1/4. I've also tested with/without > > /proc/sys/kernel/sched_energy_aware enabled (same platform) and haven't > > noticed any regression. > > > There's a lot more to unpack, but just to confirm, Vera doesn't have an EM, right? > There's no EAS with it? > (To be more precise, CPPC should bail out of building an artifical EM if there's no > or only one efficiency class: > drivers/cpufreq/cppc_cpufreq.c: > > if (bitmap_weight(used_classes, 256) <= 1) { > pr_debug("Efficiency classes are all equal (=%d). " > "No EM registered", class); > return; > } > > This is the case, right? Yes, that's correct, so my testing on Vera with EAS isn't that meaningful. Thanks, -Andrea