From: Dave Chinner <david@fromorbit.com>
To: Andi Kleen <ak@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>,
Dave Hansen <dave.hansen@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>,
xfs@oss.sgi.com, Andy Lutomirski <luto@amacapital.net>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
Tim Chen <tim.c.chen@linux.intel.com>
Subject: Re: page fault scalability (ext3, ext4, xfs)
Date: Thu, 15 Aug 2013 14:29:30 +1000 [thread overview]
Message-ID: <20130815042930.GO6023@dastard> (raw)
In-Reply-To: <20130815022401.GQ23412@tassilo.jf.intel.com>
On Wed, Aug 14, 2013 at 07:24:01PM -0700, Andi Kleen wrote:
> > And FWIW, it's no secret that XFS has more per-operation overhead
> > than ext4 through the write path when it comes to allocation, so
> > it's no surprise that on a workload that is highly dependent on
> > allocation overhead that ext4 is a bit faster....
>
> This cannot explain a worse scaling curve though?
The scaling curve is pretty much identical. The difference in
performance will be the overhead of timestamp updates through
the transaction subsystems of the filesystems.
> w-i-s is all about scaling.
Sure, but scaling *what*? It's spending all it's time in the
filesystem through the .page_mkwrite path. It's not a page fault
scaling test - it's a filesystem overwrite test that uses mmap.
Indeed, I bet if you replace the mmap() with a write(fd, buf, 4096)
loop, you'd get almost identical behaviour from the filesystems.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2013-08-15 4:29 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-14 17:10 page fault scalability (ext3, ext4, xfs) Dave Hansen
2013-08-14 19:43 ` Theodore Ts'o
2013-08-14 20:50 ` Dave Hansen
2013-08-14 23:06 ` Theodore Ts'o
2013-08-14 23:38 ` Andy Lutomirski
2013-08-15 1:11 ` Theodore Ts'o
2013-08-15 2:10 ` Dave Chinner
2013-08-15 4:32 ` Andy Lutomirski
2013-08-15 6:01 ` Dave Chinner
2013-08-15 6:14 ` Andy Lutomirski
2013-08-15 6:18 ` David Lang
2013-08-15 6:28 ` Andy Lutomirski
2013-08-15 7:11 ` Dave Chinner
2013-08-15 7:45 ` Jan Kara
2013-08-15 21:28 ` Dave Chinner
2013-08-15 21:31 ` Andy Lutomirski
2013-08-15 21:39 ` Dave Chinner
2013-08-19 23:23 ` David Lang
2013-08-19 23:31 ` Andy Lutomirski
2013-08-15 15:17 ` Andy Lutomirski
2013-08-15 21:37 ` Dave Chinner
2013-08-15 21:43 ` Andy Lutomirski
2013-08-15 22:18 ` Dave Chinner
2013-08-15 22:26 ` Andy Lutomirski
2013-08-16 0:14 ` Dave Chinner
2013-08-16 0:21 ` Andy Lutomirski
2013-08-16 22:02 ` J. Bruce Fields
2013-08-16 23:18 ` Andy Lutomirski
2013-08-18 20:17 ` J. Bruce Fields
2013-08-19 22:17 ` J. Bruce Fields
2013-08-19 22:29 ` Andy Lutomirski
2013-08-15 15:14 ` Dave Hansen
2013-08-15 0:24 ` Dave Chinner
2013-08-15 2:24 ` Andi Kleen
2013-08-15 4:29 ` Dave Chinner [this message]
2013-08-15 15:36 ` Dave Hansen
2013-08-15 15:09 ` Dave Hansen
2013-08-15 15:05 ` Theodore Ts'o
2013-08-15 17:45 ` Dave Hansen
2013-08-15 19:31 ` Theodore Ts'o
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