From mboxrd@z Thu Jan  1 00:00:00 1970
From: Zheng Liu <gnehzuil.liu@gmail.com>
Subject: Re: ext4_fallocate
Date: Mon, 2 Jul 2012 11:16:11 +0800
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Cc: Theodore Ts'o <tytso@mit.edu>, Fredrick <fjohnber@zoho.com>,
	Ric Wheeler <rwheeler@redhat.com>, linux-ext4@vger.kernel.org,
	Andreas Dilger <adilger@dilger.ca>, wenqing.lz@taobao.com
To: Eric Sandeen <sandeen@redhat.com>
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On Wed, Jun 27, 2012 at 07:02:45PM -0400, Eric Sandeen wrote:
> On 6/27/12 3:30 PM, Theodore Ts'o wrote:
> > A better workload would be to use a blocksize of 4k.  By using a
> > blocksize of 1024k, it's not surprising that the metadata overhead is
> > in the noise.
> > 
> > Try something like this; this will cause the extent tree overhead to
> > be roughly equal to the data block I/O.
> > 
> > [global]
> > rw=randwrite
> > size=128m
> > filesize=1g
> > bs=4k
> > ioengine=sync
> > fallocate=1
> > fsync=1
> > 
> > [thread1]
> > filename=testfile

Hi Eric,

Could you please run this test with 'journal_async_commit' flag.  In my
previous test, this feature can dramatically improve the performance of
uninitialized extent conversion.

I have sent an email to do a similar test [1].  In that email, I do a
similar test and the journal_async_commit flag quite can improve the
performance.

1. http://comments.gmane.org/gmane.linux.file-systems/63569

Regards,
Zheng