From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>, linux-scsi <linux-scsi@vger.kernel.org>,
Gluk <git.user@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
xfs@oss.sgi.com, Christoph Hellwig <hch@infradead.org>,
Sergey Meirovich <rathamahata@gmail.com>
Subject: Re: Terrible performance of sequential O_DIRECT 4k writes in SAN environment. ~3 times slower then Solars 10 with the same HBA/Storage.
Date: Mon, 20 Jan 2014 05:58:55 -0800 [thread overview]
Message-ID: <20140120135855.GA26280@infradead.org> (raw)
In-Reply-To: <20140115220721.GY3469@dastard>
On Thu, Jan 16, 2014 at 09:07:21AM +1100, Dave Chinner wrote:
> Yes, I think it can be done relatively simply. We'd have to change
> the code in xfs_file_aio_write_checks() to check whether EOF zeroing
> was required rather than always taking an exclusive lock (for block
> aligned IO at EOF sub-block zeroing isn't required),
That's not even required for supporting aio appends, just a further
optimization for it.
> and then we'd
> have to modify the direct IO code to set the is_async flag
> appropriately. We'd probably need a new flag to say tell the DIO
> code that AIO beyond EOF is OK, but that isn't hard to do....
Yep, need a flag to allow appending writes and then defer them.
> Christoph, are you going to get any time to look at doing this in
> the next few days?
I'll probably need at least another week before I can get to it. If you
wanna pick it up before than feel free.
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next prev parent reply other threads:[~2014-01-20 13:58 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-06 9:38 Terrible performance of sequential O_DIRECT 4k writes in SAN environment. ~3 times slower then Solars 10 with the same HBA/Storage Sergey Meirovich
2014-01-06 20:10 ` Jan Kara
2014-01-07 9:13 ` Sergey Meirovich
2014-01-07 15:58 ` Christoph Hellwig
2014-01-07 18:37 ` Sergey Meirovich
2014-01-08 14:03 ` Christoph Hellwig
2014-01-08 14:43 ` Sergey Meirovich
2014-01-08 15:26 ` Christoph Hellwig
2014-01-08 17:30 ` Sergey Meirovich
2014-01-08 20:55 ` Jan Kara
2014-01-09 10:11 ` Sergey Meirovich
2014-01-10 9:36 ` Jan Kara
2014-01-10 10:36 ` Sergey Meirovich
2014-01-10 10:48 ` Jan Kara
2014-01-10 14:32 ` Sergey Meirovich
2014-01-10 18:14 ` Sergey Meirovich
2014-01-14 13:30 ` Sergey Meirovich
2014-01-15 22:07 ` Dave Chinner
2014-01-20 13:58 ` Christoph Hellwig [this message]
2014-01-20 22:18 ` Dave Chinner
2014-01-08 1:17 ` Jan Kara
2014-01-08 14:03 ` Christoph Hellwig
2014-01-07 20:57 ` James Smart
2014-01-08 13:57 ` Sergey Meirovich
2014-01-09 19:54 ` Douglas Gilbert
2014-01-09 21:26 ` Sergey Meirovich
2014-01-09 21:43 ` Sergey Meirovich
-- strict thread matches above, loose matches on Subject: below --
2014-01-06 13:16 Sergey Meirovich
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