[rfc] Replacing FNV and hash32 with Paul Hsieh's SuperFastHash

[Alexander Leidinger]

Quoting Gleb Kurtsou <gleb.kurtsou at gmail.com> (from Fri, 24 Dec 2010  
00:46:20 +0200):

> Hi,
>
> I've recently noticed that hash table use in nullfs was inefficient, 1/3
> to half of buckets remained unused. I've started investigating it
> further and came across SuperFastHash hashing function, SFH
> (SuperFastHash) has BSD license, used in WebKit and other open source
> projects. Detailed description and Comparision with FNV and Bob Jenkin's
> hash can be found here:
> http://www.azillionmonkeys.com/qed/hash.html

I found some web pages which tell about an unfair speed comparision  
and about a collision problem in SFH:
   
http://coding.derkeiler.com/Archive/General/comp.programming/2005-03/0650.html
  http://www.team5150.com/~andrew/blog/2007/03/breaking_superfasthash.html
  http://blog.clawpaws.net/post/2007/04/22/Good-Hash-Functions

It may be that this is not an issue for the use case we have here, but  
blindly replacing it without looking at the above web pages looks a  
little bit risky to me.

Bye,
Alexander.

-- 
The use of money is all the advantage there is to having money.
		-- Benjamin Franklin

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