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    SubjectRe: [PATCH] percpu_counter: FBC_BATCH might be too big
    From: Eric Dumazet <>
    Date: Fri, 05 Dec 2008 17:05:16 +0100

    > For NR_CPUS >= 16 values, FBC_BATCH is 2*NR_CPUS
    > Considering more and more distros are using high NR_CPUS values,
    > it makes sense to use a more sensible value for FBC_BATCH.
    > A sensible value is 2*num_online_cpus(), with a minimum value of 32
    > (This minimum value helps branch prediction in __percpu_counter_add())
    > We already have a hotcpu notifier, so we can adjust FBC_BATCH dynamically.
    > Signed-off-by: Eric Dumazet <>

    The downside is now we must load this value in these common
    routines. But I think the gain outweights the loss so:

    Acked-by: David S. Miller <>

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