On Thu, Feb 12, 2009 at 4:11 AM, Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxxxxxx> wrote: > The current jhash.h implements the lookup2() hash function by Bob Jenkins. > However, lookup2() is outdated as Bob wrote a new hash function called > lookup3(). The new hash function > > - mixes better than lookup2(): it passes the check that every input bit > changes every output bit 50% of the time, while lookup2() failed it. > - performs better: compiled with -O2 on Core2 Duo, lookup3() 20-40% faster > than lookup2() depending on the key length. Well, there's another question which is not addressed by Bob Jenkins' design docs: Kernel code usually runs cache-cold, whereas Bob Jenkins did most of his testing cache-hot in tight loops. If you compile both lookup2 and lookup3 with -Os and run them in a loop with a cache flush, how well do they compare then? Cheers, Kyle Moffett -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
