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poking at all that got me > these patches. > > They're in queue.git/sched/core and I spend most of yesterday staring at traces > trying to find anything wrong. So far, so good. > > Please test. > > Analysis of commit bdba3187771c ("sched/fair: Use full weight to __calc_delta()") confirms it resolves a scaling bottleneck present in the v7.0-rc baseline (cee73b1e840c). On Ampere Altra (80 cores) non-SMT SMP with CONFIG_NOHZ_FULL and CONFIG_SCHED_CLUSTER enabled, the baseline suffered from vruntime distortion that caused significant scheduling jitter, resulting in measurable performance cliffs under high parallel load. Llama AIO for Inference Scaling : The baseline shows a performance cliffs at high thread counts, due to the scheduler miscalculating time slices for tail threads, which forced the entire synchronous inference batch to wait. The patch corrects the delta calculation for predictable scaling. n_threads Baseline (cee73b1e840c) Patched (bdba3187771c) Diff 51 8.46 t/s 12.12 t/s +43.3% 52 17.75 t/s 22.26 t/s +25.4% 64 12.40 t/s 14.66 t/s +18.2% Hackbench scaling in the baseline was non-linear indicating excessive scheduling overhead as process counts increased. By using the full weight for delta calculations, the patch reduces unnecessary migrations and improves message throughput. Task Count Baseline(sec) Patched(sec) Throughput 16 Processes 51.25s 44.09s +16.2% 32 Processes 92.42s 78.09s +18.3% Tested-by: Shubhang Kaushik Regards, Shubhang Kaushik