Messages in this thread | | | Date | Fri, 05 Dec 2008 12:32:02 -0800 (PST) | Subject | Re: [PATCH] percpu_counter: FBC_BATCH might be too big | From | David Miller <> |
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From: Eric Dumazet <dada1@cosmosbay.com> 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 <dada1@cosmosbay.com>
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 <davem@davemloft.net>
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