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Wysocki" , Andrea Righi , Len Brown , , References: <20260608-rneri-fix-cas-clusters-v4-0-1526711c944c@linux.intel.com> <20260608-rneri-fix-cas-clusters-v4-1-1526711c944c@linux.intel.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20260608-rneri-fix-cas-clusters-v4-1-1526711c944c@linux.intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ1PEPF000023DA:EE_|IA1PR12MB8312:EE_ X-MS-Office365-Filtering-Correlation-Id: 3bcd198f-0760-4275-97b5-08dec5df5369 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700016|82310400026|376014|7416014|1800799024|921020|56012099006|11063799006|4143699003|22082099003|18002099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb08.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(36860700016)(82310400026)(376014)(7416014)(1800799024)(921020)(56012099006)(11063799006)(4143699003)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: D7/egUMOu0+dj4f8QgcwmSFhV+4J+JlHEdCRdsY87VCBtkhQHAcJAG2t29JUhw9tkci/Hrtmww25qk2/j25mplWrWkPU2yyhD5lvjc5xVYo6wa0pni9KqtxBOFDV2YH7IYUWPEayfMr48+lHV3Yhujq8j9Id/a1xyMPRdhiN4/SiATkFY6t1363odSfuhV5F10S6L55Wjr+UGRHv9VWZOU3U+W+6LFSfAWQZ8DhRhJPrFyew08huWyaaIfYyMTfMcdcB/h4H6ThvTAg38ZNfPgsq+eZr+KH/XHaHZuPg+HRIVIV+0GTc2JZbbAS0DnP0/E60vIz70lzOzwvGXPmqQQzDs8TYSioIUyg03DGsnEEARUc4W4DlMO8b6P5MIAA8XOOu2/KVRY/CShlSVlv8Nsb/sv3tXBVN8Rq/tCe+L9XcMIfgzoH11vTkYt97sXpX X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Jun 2026 04:26:50.0218 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 3bcd198f-0760-4275-97b5-08dec5df5369 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=[satlexmb08.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SJ1PEPF000023DA.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB8312 Hello Ricardo, On 6/8/2026 6:27 PM, Ricardo Neri wrote: > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index f4ed841f766f..229f32cebf1f 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -12924,6 +12924,7 @@ static struct rq *sched_balance_find_src_rq(struct lb_env *env, > int i; > > for_each_cpu_and(i, sched_group_span(group), env->cpus) { > + bool smt_degraded_cap = sched_smt_active() && !is_core_idle(i); Based on a quick look at the generated asm, we seem to be calculating "smt_degraded_cap" regardless of whether we are on a "SD_ASYM_CPUCAPACITY" domain or not which is an unnecessary overhead of doing a is_core_idle() on symmetric domains. We can have an indicator up top like: bool asym_balance = !!(env->sd->flags & SD_ASYM_CPUCAPACITY); and later use that when computing smt_degraded_cap: bool smt_degraded_cap = asym_balance && (sched_smt_active() && !is_core_idle(i)); I would even suggest pushing this until later and do ... > unsigned long capacity, load, util; > unsigned int nr_running; > enum fbq_type rt; > @@ -12964,8 +12965,12 @@ static struct rq *sched_balance_find_src_rq(struct lb_env *env, > * eventually lead to active_balancing high->low capacity. > * Higher per-CPU capacity is considered better than balancing > * average load. > + * > + * Busy SMT siblings reduce the capacity of CPU i. Do not skip > + * it in this case. > */ > if (env->sd->flags & SD_ASYM_CPUCAPACITY && ... if (asym_balance) { /* Busy SMT reduces capacity */ if (sched_smt_active() && !is_core_idle(i)) continue; /* Other bits */ if (...) continue; } Thoughts? Aside from that, the changes makes sense to me. Feel free to include: Reviewed-by: K Prateek Nayak > + !smt_degraded_cap && > !capacity_greater(capacity_of(env->dst_cpu), capacity) && > nr_running == 1) > continue; > > -- > 2.43.0 > -- Thanks and Regards, Prateek