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From: Eric Sandeen <sandeen@redhat.com>
To: ext4 development <linux-ext4@vger.kernel.org>
Subject: More testing: 4x parallel 2G writes, sequential reads
Date: Wed, 07 Nov 2007 16:42:59 -0600	[thread overview]
Message-ID: <47323F73.5080708@redhat.com> (raw)

I tried ext4 vs. xfs doing 4 parallel 2G IO writes in 1M units to 4
different subdirectories of the root of the filesystem:

http://people.redhat.com/esandeen/seekwatcher/ext4_4_threads.png
http://people.redhat.com/esandeen/seekwatcher/xfs_4_threads.png
http://people.redhat.com/esandeen/seekwatcher/ext4_xfs_4_threads.png

and then read them back sequentially:

http://people.redhat.com/esandeen/seekwatcher/ext4_4_threads_read.png
http://people.redhat.com/esandeen/seekwatcher/xfs_4_threads_read.png
http://people.redhat.com/esandeen/seekwatcher/ext4_xfs_4_read_threads.png

At the end of the write, ext4 had on the order of 400 extents/file, xfs
had on the order of 30 extents/file.  It's clear especially from the
read graph that ext4 is interleaving the 4 files, in about 5M chunks on
average.  Throughput seems comparable between ext4 & xfs nonetheless.

Again this was on a decent HW raid so seek penalties are probably not
too bad.

-Eric

             reply	other threads:[~2007-11-07 22:43 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-07 22:42 Eric Sandeen [this message]
2007-11-07 23:09 ` More testing: 4x parallel 2G writes, sequential reads Andreas Dilger
2007-11-07 23:18   ` Eric Sandeen
2007-11-08  3:39   ` Eric Sandeen
2007-11-07 23:17 ` Alex Tomas
2007-11-08  0:14 ` Shapor Naghibzadeh
2007-11-08  3:06   ` Eric Sandeen

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