sched/fair: Only do asym_packing load balancing from fully idle SMT cores

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When balancing load between cores, all the SMT siblings of the destination
CPU, if any, must be idle. Otherwise, pulling new tasks degrades the
throughput of the busy SMT siblings. The overall throughput of the system
remains the same.

When balancing load within an SMT core this consideration is not relevant.
Follow the priorities that hardware indicates.

Suggested-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20230406203148.19182-3-ricardo.neri-calderon@linux.intel.com

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Ricardo Neri 2023-04-06 13:31:38 -07:00 • committed by Peter Zijlstra

parent 8b36d07f1d

commit eefefa716c

1 changed files with 40 additions and 16 deletions

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kernel/sched/fair.c

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