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Date: Fri, 14 Dec 2007 12:20:31 +0100 From: Patrick McHardy <kaber@...sh.net> To: Eric Dumazet <dada1@...mosbay.com> CC: netfilter-devel@...r.kernel.org, netdev@...r.kernel.org Subject: Re: [NETFILTER] xt_hashlimit : speedups hash_dst() Eric Dumazet wrote: > 1) Using jhash2() instead of jhash() is a litle bit faster if applicable. > > 2) Thanks to jhash, hash value uses full 32 bits. > Instead of returning hash % size (implying a divide) > we return the high 32 bits of the (hash * size) that will > give results between [0 and size-1] and same hash distribution. > > On most cpus, a multiply is less expensive than a divide, by an order > of magnitude. Clever :) Applied, thanks Eric. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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