From: "Brian F. G. Bidulock" <bidulock@openss7.org>
To: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: David Miller <davem@davemloft.net>,
draghuram@rocketmail.com, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org
Subject: Re: Question about tcp hash function tcp_hashfn()
Date: Thu, 1 Jun 2006 01:11:25 -0600 [thread overview]
Message-ID: <20060601011125.C22283@openss7.org> (raw)
In-Reply-To: <20060601070136.GA754@2ka.mipt.ru>; from johnpol@2ka.mipt.ru on Thu, Jun 01, 2006 at 11:01:36AM +0400
Evgeniy,
On Thu, 01 Jun 2006, Evgeniy Polyakov wrote:
> On Thu, Jun 01, 2006 at 12:46:08AM -0600, Brian F. G. Bidulock (bidulock@openss7.org) wrote:
> > > Since pseudo-randomness affects both folded and not folded hash
> > > distribution, it can not end up in different results.
> >
> > Yes it would, so to rule out pseudo-random effects the pseudo-
> > random number generator must be removed.
> >
> > >
> > > You are right that having test with 2^48 values is really interesting,
> > > but it will take ages on my test machine :)
> >
> > Try a usable subset; no pseudo-random number generator.
>
> I've run it for 2^30 - the same result: folded and not folded Jenkins
> hash behave the same and still both results produce exactly the same
> artifacts compared to XOR hash.
But not without the pseudo-random number generation... ?
>
> Btw, XOR hash, as completely stateless, can be used to show how
> Linux pseudo-random generator works for given subset - it's average of
> distribution is very good.
But its distribution might auto-correlate with the Jenkins function.
The only way to be sure is to remove the pseudo-random number generator.
Just try incrementing from, say, 10.0.0.0:10000 up, resetting port number
to 10000 at 16000, and just incrementing the IP address when the port
number wraps, instead of pseudo-random, through 2^30 loops for both.
If the same artifacts emerge, I give in.
Can you show the same artifacts for jenkins_3word?
next prev parent reply other threads:[~2006-06-01 7:11 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-31 4:29 Question about tcp hash function tcp_hashfn() Raghuram
2006-05-31 5:55 ` Brian F. G. Bidulock
2006-05-31 7:10 ` David Miller
2006-05-31 7:45 ` Brian F. G. Bidulock
2006-05-31 7:49 ` David Miller
2006-05-31 8:00 ` Brian F. G. Bidulock
2006-05-31 9:03 ` Evgeniy Polyakov
2006-05-31 9:12 ` David Miller
2006-05-31 9:44 ` Evgeniy Polyakov
2006-05-31 9:51 ` Brian F. G. Bidulock
2006-05-31 10:58 ` Evgeniy Polyakov
2006-05-31 11:04 ` Evgeniy Polyakov
2006-05-31 13:06 ` Evgeniy Polyakov
2006-05-31 18:29 ` Brian F. G. Bidulock
2006-06-01 6:12 ` Evgeniy Polyakov
2006-06-01 6:18 ` David Miller
2006-06-01 6:22 ` Brian F. G. Bidulock
2006-06-01 6:24 ` David Miller
2006-05-31 18:41 ` David Miller
2006-06-01 6:04 ` Evgeniy Polyakov
2006-06-01 6:18 ` Brian F. G. Bidulock
2006-06-01 6:30 ` Evgeniy Polyakov
2006-06-01 6:46 ` Brian F. G. Bidulock
2006-06-01 7:01 ` Evgeniy Polyakov
2006-06-01 7:11 ` Brian F. G. Bidulock [this message]
2006-06-01 8:38 ` Evgeniy Polyakov
2006-06-01 10:24 ` Brian F. G. Bidulock
2006-06-01 11:06 ` Evgeniy Polyakov
2006-06-01 18:40 ` Brian F. G. Bidulock
2006-06-01 20:21 ` David Miller
2006-06-02 7:01 ` Evgeniy Polyakov
2006-06-02 5:40 ` Florian Weimer
2006-06-02 7:48 ` Evgeniy Polyakov
2006-06-02 15:10 ` Brian F. G. Bidulock
2006-06-02 17:26 ` Florian Weimer
2006-06-02 17:37 ` Brian F. G. Bidulock
2006-05-31 9:52 ` Brian F. G. Bidulock
2006-05-31 8:49 ` Brian F. G. Bidulock
2006-05-31 9:02 ` David Miller
2006-05-31 9:39 ` Brian F. G. Bidulock
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