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Date:      Thu, 27 Sep 2001 23:06:39 +0200
From:      Wilko Bulte <wkb@freebie.xs4all.nl>
To:        Julian Elischer <julian@vicor-nb.com>
Cc:        current@FreeBSD.ORG
Subject:   Re: RFC: mod for 'du'
Message-ID:  <20010927230639.A97964@freebie.xs4all.nl>
In-Reply-To: <3BB3936A.D1E1F6B3@vicor-nb.com>; from julian@vicor-nb.com on Thu, Sep 27, 2001 at 02:00:26PM -0700
References:  <3BB3936A.D1E1F6B3@vicor-nb.com>

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On Thu, Sep 27, 2001 at 02:00:26PM -0700, Julian Elischer wrote:
> 'du' keeps an array of files it has encountered that have > 1 link.
> Whenever it encounters another, it checks to see if it's one it has
> already seen
> and thus can avoid counting its space twice..
> 
> This is ok for small filesystems, however VICOR maintains
> 500GB filesystems on which much of the data has several links.
> 
> The following patch to replace the linear array (which it realocs if too
> small)
> (which it scans linearly) with a hash-table can makle a DRASTIC change
> to how DU perfomrs for us in this environment.
> 
> In a small test, we made a linked copy of /usr/src
> 
> the run times were:
> old: 0.410u 2.221s 1:55.41 2.2%      12+1355k 6325+0io 2pf+0w
> new: 8.610u 2.665s 2:09.23 8.7%      10+718k 6367+0io 2pf+0  

swap(old,new) I suppose?

-- 
|   / o / /_  _   		email: 	wilko@FreeBSD.org
|/|/ / / /(  (_)  Bulte		Arnhem, The Netherlands	

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