From: Rusty Russell <rusty@rustcorp.com.au>
To: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
netfilter-devel@vger.kernel.org
Subject: Re: [PATCH] Update jhash.h with the new version of Jenkins' hash
Date: Thu, 12 Feb 2009 13:28:42 +1030 [thread overview]
Message-ID: <200902121328.43749.rusty@rustcorp.com.au> (raw)
In-Reply-To: <alpine.DEB.2.00.0902111107480.15665@blackhole.kfki.hu>
On Wednesday 11 February 2009 20:49:20 Jozsef Kadlecsik wrote:
> Hi,
>
> 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 However, lookup2() is outdated as Bob wrote a new hash function called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() is 20-40%
> faster than lookup2() depending on the key length.
Hi Joszef,
My concern was that it's also bigger (and we inline it). Performance is
pretty much a wash since we so rarely hash more than a few words.
Any stats on code size changes?
Rusty.
next prev parent reply other threads:[~2009-02-12 2:58 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-11 10:19 [PATCH] Update jhash.h with the new version of Jenkins' hash Jozsef Kadlecsik
2009-02-11 20:19 ` Michał Mirosław
2009-02-11 22:50 ` Jozsef Kadlecsik
2009-02-11 23:23 ` Michał Mirosław
2009-02-12 0:12 ` wli
2009-02-12 0:29 ` David Miller
2009-02-12 0:41 ` Jan Engelhardt
2009-02-12 9:05 ` Jarek Poplawski
2009-02-12 9:55 ` Jarek Poplawski
2009-02-12 9:11 ` Jozsef Kadlecsik
2009-02-12 9:16 ` Patrick McHardy
2009-02-12 9:41 ` Jozsef Kadlecsik
2009-02-12 13:46 ` Kyle Moffett
2009-02-17 17:13 ` Jozsef Kadlecsik
2009-02-18 5:11 ` Rusty Russell
2009-02-18 11:50 ` Ilpo Järvinen
2009-02-12 19:58 ` Eric W. Biederman
2009-02-12 2:58 ` Rusty Russell [this message]
-- strict thread matches above, loose matches on Subject: below --
2009-02-10 19:40 Jozsef Kadlecsik
2009-02-10 21:19 ` Scott Feldman
2009-02-10 22:03 ` Jozsef Kadlecsik
2009-02-11 1:17 ` David Miller
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