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Re: IP Upstream Hash

chateau Xiao
August 03, 2011 09:48PM
do you mean, in the next version, murmur2 hash function will be used in
nginx?

and do you show the benchmark between the orignial algorithm and the new
one?

On Thu, Jul 21, 2011 at 5:43 PM, Igor Sysoev <igor@sysoev.ru> wrote:

> On Wed, Jul 20, 2011 at 02:18:52PM -0700, Matthieu Tourne wrote:
> > Hi all,
> >
> > I was looking at the code in ngx_http_upstream_ip_hash_module.c
> > And I'm not sure where the hashing algorithm for IPs is coming from,
> > especially those lines :
> >
> > iphp->hash = 89;
> >
> > hash = (hash * 113 + iphp->addr[i]) % 6271;
> >
> > Just wondering if those constants are arbitrary chosen, or if there is
> > something there to guarantee a good distribution ?
> >
> > If you have some links explaining this algorithm, it would be greatly
> > appreciated!
> > Also, how would you get a good distribution on IPv6. Maybe it would make
> > sense to use murmur ?
>
> This algorithm came from FastMail.fm. Murmur2 may be better, I'm going
> to use it in upcoming upstream hash module which allows to hash any
> expression.
>
>
> --
> Igor Sysoev
>
> _______________________________________________
> nginx-devel mailing list
> nginx-devel@nginx.org
> http://mailman.nginx.org/mailman/listinfo/nginx-devel
>
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Subject Author Views Posted

IP Upstream Hash

Matthieu Tourne 2724 July 20, 2011 05:20PM

Re: IP Upstream Hash

chateau Xiao 877 July 20, 2011 11:14PM

Re: IP Upstream Hash

Igor Sysoev 1512 July 21, 2011 05:44AM

Re: IP Upstream Hash

chateau Xiao 818 August 03, 2011 09:48PM

Re: IP Upstream Hash

Oscar Fernandez 794 August 04, 2011 03:10AM

Re: IP Upstream Hash

Igor Sysoev 1181 August 04, 2011 07:12AM



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