Subject: Re: [Ext2-devel] Re: [RFC] extents,delayed allocation,mballoc for
	ext3
From: Mingming Cao <cmm@us.ibm.com>
To: Alex Tomas <alex@clusterfs.com>
Cc: ext2-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
In-Reply-To: <m3ekqqoj3m.fsf@bzzz.home.net>
References: <m365c3pthi.fsf@bzzz.home.net>  <m3ekqqoj3m.fsf@bzzz.home.net>
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Date: 14 Apr 2004 10:49:59 -0700
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On Wed, 2004-04-14 at 05:10, Alex Tomas wrote:
> 
> I've just benched ext3 vs. ext3+reservation vs. ext3+delalloc vs. xfs.
> it was tiobench.
> ext3                          1024  4096   32    8.12 9.872%     8.111    82
> ext3-dalloc                   1024  4096   32   24.83 20.01%     2.995   124
> ext3-reserv                   1024  4096   32   22.72 29.51%     3.282    77
> xfs                           1024  4096   32   25.47 21.75%     2.247   117
> 
Hi Alex,

Nice comparison! The ext3 reservation system use more cpus because we do
reservations in memory( not on disk) and we have a global lock per
filesystem to guard the operation.  The current search for a new
reservation window algorithm is not perfect right now.  

extents and delayed allocation probably is the right way to go for next
generation (maybe ext4).  Currently I just try to fix the missing
preallocation feature in ext3, without break the disk compatibility and
involve too much changes....

Thanks for your interest.

Mingming

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