sched/fair: optimize the PLACE_LAG when se->vlag is zero

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When PLACE_LAG is enabled, from the relationship:
            vl_i = (W + w_i)*vl'_i / W
we know that if vl'_i(se->vlag) is zero, the vl_i is zero too.

So if se->vlag is zero, there is no need to waste cycles to
do the calculation.

Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Christoph Lameter (Ampere) <cl@linux.com>
Link: https://lkml.kernel.org/r/20241001070021.10626-1-shijie@os.amperecomputing.com

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Huang Shijie 2024-10-01 15:00:21 +08:00 • committed by Peter Zijlstra

parent e31488c9df

commit 4423af84b2

1 changed files with 1 additions and 1 deletions

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kernel/sched/fair.c

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