From: Mike Fedyk <mfedyk@matchmail.com>
To: Andrew Morton <akpm@zip.com.au>
Cc: Daniel Phillips <phillips@bonn-fries.net>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [CFT] delayed allocation and multipage I/O patches for 2.5.6.
Date: Wed, 13 Mar 2002 13:51:18 -0800 [thread overview]
Message-ID: <20020313215118.GA460@matchmail.com> (raw)
In-Reply-To: <3C8D9999.83F991DB@zip.com.au> <E16kkcq-0001rV-00@starship> <3C8E6C63.E8B72195@zip.com.au> <E16l7Oe-0000Dk-00@starship> <3C8FAD88.1C425F9B@zip.com.au>
In-Reply-To: <3C8FAD88.1C425F9B@zip.com.au>
On Wed, Mar 13, 2002 at 11:50:32AM -0800, Andrew Morton wrote:
> Now, I think it's fair to say that the ext2/ext3 inter-file fragmentation
> issue is one of the three biggest performance problems in Linux. (The
> other two being excessive latency in the page allocator due to VM writeback
> and read latency in the I/O scheduler).
>
> The fix for interfile fragmentation lies inside ext2/ext3, not inside
> any generic layers of the kernel. And this really is a must-fix,
> because the completion time for writeback is approximately proportional
> to the size of the filesystem. So we're getting, what? Fifty percent
> slower per year?
>
> The `tar xfz linux.tar.gz ; sync' workload can be sped up 4x-5x by
> using find_group_other() for directories. I spent a week or so
> poking at this when it first came up. Basically, *everything*
> which I did to address the rapid-growth problem ended up penalising
> the slow-growth fragmentation - long-term intra-file fragmentation
> suffered at the expense of short-term inter-file fragmentation.
I know ReiserFS has similar problems.
Can anyone say wheather JFS or XFS has this problem also?
next prev parent reply other threads:[~2002-03-13 21:50 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-12 6:00 [CFT] delayed allocation and multipage I/O patches for 2.5.6 Andrew Morton
2002-03-12 11:18 ` Daniel Phillips
2002-03-12 20:29 ` Andrew Morton
2002-03-12 20:40 ` Daniel Phillips
2002-03-12 11:39 ` Daniel Phillips
2002-03-12 21:00 ` Andrew Morton
2002-03-13 11:58 ` Daniel Phillips
2002-03-13 19:50 ` Andrew Morton
2002-03-13 21:51 ` Mike Fedyk [this message]
2002-03-14 11:59 ` Daniel Phillips
2002-03-13 0:42 ` David Woodhouse
2002-03-18 19:16 ` Hanna Linder
2002-03-18 20:14 ` Andrew Morton
2002-03-18 20:22 ` Hanna Linder
2002-03-18 20:49 ` Andrew Morton
2002-03-19 0:41 rwhron
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