From: Wu Fengguang <fengguang.wu@intel.com>
To: "linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Cc: Jan Kara <jack@suse.cz>, Li Shaohua <shaohua.li@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Theodore Ts'o <tytso@mit.edu>
Subject: Re: ext4 data=writeback performs worse than data=ordered now
Date: Wed, 14 Dec 2011 22:03:05 +0800 [thread overview]
Message-ID: <20111214140305.GA21664@localhost> (raw)
In-Reply-To: <20111214140025.GA19650@localhost>
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On Wed, Dec 14, 2011 at 10:00:25PM +0800, Wu Fengguang wrote:
> > The worst case happens for the USB key, where both old/new kernels
> > see ~10% worse performance for data=writeback.
>
> > ext4 ext4:wb
> > ------------------------ ------------------------
> > 6.20 -10.6% 5.54 fat/UKEY-thresh=100M/ext4-1dd-1-3.2.0-rc3-pause6+
>
> Some more comparison numbers for the above worst case.
>
> I don't see obvious differences from the balance_dirty_pages graphs,
Ah there seem to be many more blocks in write_begin(), indicated by
the more negative pause times in the attached second graph.
Thanks,
Fengguang
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next prev parent reply other threads:[~2011-12-14 14:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-14 13:34 ext4 data=writeback performs worse than data=ordered now Wu Fengguang
[not found] ` <20111214140025.GA19650@localhost>
2011-12-14 14:03 ` Wu Fengguang [this message]
2011-12-14 14:30 ` Ted Ts'o
2011-12-14 14:49 ` Wu Fengguang
2011-12-14 14:52 ` Tao Ma
2011-12-14 15:02 ` Wu Fengguang
2011-12-15 1:02 ` Shaohua Li
2011-12-15 1:00 ` Wu Fengguang
2011-12-15 1:27 ` NeilBrown
2011-12-15 1:34 ` Wu Fengguang
2011-12-15 5:02 ` Wu Fengguang
2011-12-15 1:20 ` Darrick J. Wong
2011-12-15 1:42 ` Shaohua Li
2011-12-15 18:10 ` Darrick J. Wong
2011-12-16 1:47 ` Shaohua Li
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