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From: Daniel Phillips <phillips@bonn-fries.net>
To: Hans Reiser <reiser@namesys.com>
Subject: Re: Ext2 directory index: ALS paper and benchmarks
Date: Thu, 6 Dec 2001 04:54:31 +0100
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Hi Hans,

On December 6, 2001 04:41 am, you wrote:
> I can't comment on your benchmarks because I was on the way to bed when 
> I read this.  I am sure though that you and Stephen are doing your usual 
> good programming.
> 
> ReiserFS is an Htree by your definition in your paper, yes?

You've got a hash-keyed b*tree over there.  The htree is fixed depth.

> Daniel Phillips wrote:
> >So it seems that for realistic cases, ext2+htree outperforms reiserfs 
> >quite dramatically.  (Are you reading, Hans?  Fighting words... ;-)
> 
> Have you ever seen an application that creates millions of files create 
> them in random order?

We haven't seen an application create millions of files yet.  However, the 
effects I'm describing are readily apparent at much smaller numbers.

> Almost always there is some non-randomness in the 
> order, and our newer hash functions are pretty good at preserving it. 
>  Applications that create millions of files are usually willing to play 
> nice for an order of magnitude performance gain also.....

To be fair, I should rerun the tests with your linear-congruential hash, I'll 
try to get time for that.

--
Daniel
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