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From: Christoph Hellwig <hch@infradead.org>
To: Zheng Da <zhengda1936@gmail.com>
Cc: xfs@oss.sgi.com
Subject: Re: concurrent direct IO write in xfs
Date: Mon, 16 Jan 2012 12:48:19 -0500	[thread overview]
Message-ID: <20120116174819.GA19417@infradead.org> (raw)
In-Reply-To: <CAFLer83FBZG9ZCrT2jUZBcTC2a2tx_CDmykyPF4cTP0dbHGw7Q@mail.gmail.com>

On Sun, Jan 15, 2012 at 07:01:42PM -0500, Zheng Da wrote:
> Hello,
> 
> I surprisedly found that writing data to a file (no appending) with direct
> IO and with multiple threads has the same performance as a single thread.
> Actually, it seems there is only one core is working at a time. In my case,
> each time I write a page to a file and the offset is always aligned to the
> page size, so there is no overlapping between writes.

What kernel version are you using?  Also, what is the exact I/O
pattern?

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  reply	other threads:[~2012-01-16 17:48 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-16  0:01 concurrent direct IO write in xfs Zheng Da
2012-01-16 17:48 ` Christoph Hellwig [this message]
2012-01-16 19:44   ` Zheng Da
2012-01-16 23:25 ` Dave Chinner
2012-01-17 19:19   ` Zheng Da
2012-01-20  8:53     ` Linda Walsh
2012-01-20 15:07       ` Zheng Da
2012-01-23  5:11     ` Dave Chinner
2012-01-23 19:34       ` Zheng Da
2012-01-23 20:51         ` Zheng Da
2012-01-24  0:34           ` Stan Hoeppner
2012-01-24  1:40             ` Zheng Da
2012-01-24  3:54           ` Dave Chinner
2012-01-25 21:20             ` Zheng Da
2012-01-25 22:25               ` Dave Chinner
2012-02-09  6:09             ` Dave Chinner
2012-02-09  6:44               ` Zheng Da
2012-02-13 17:48               ` Christoph Hellwig
2012-02-13 23:07                 ` Dave Chinner

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