Re: XFS performance issues: O_DIRECT and Linux 2.6.6+

To:	james.foris@xxxxxxxxxx
Subject:	Re: XFS performance issues: O_DIRECT and Linux 2.6.6+
From:	James Foris <james.foris@xxxxxxxxxx>
Date:	Mon, 13 Sep 2004 10:06:52 -0500
Cc:	Nathan Scott <nathans@xxxxxxx>, linux-xfs@xxxxxxxxxxx
In-reply-to:	<4144B19A.2020407@med.ge.com>
References:	<411A8410.2030000@med.ge.com> <20040910041106.GA14336@frodo> <4144B19A.2020407@med.ge.com>
Reply-to:	james.foris@xxxxxxxxxx
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James Foris wrote:

Nathan Scott wrote:
On Wed, Aug 11, 2004 at 03:39:44PM -0500, James Foris wrote:
I have been using XFS in both IRIX and Linux for many years now, and overall I am quite happy with it - recommend it to everyone, run it on my home systems, etc.

But, recently I ran into something that I need some help in understanding/explaining. The title says it all, really, but the details follow below.
Hi there,
Before I forget completely, from talking to Christoph a few
days back he suggested that the problems you were seeing may
have been resolved by some fixes that have gone into the tree
in the last week or two (they certainly touch this area) - if
you could retry your tests and let us know whether you still
see this degredation on Linus' current -bk tree, that would
be much appreciated!


OK, I have run the sequence and it happened between 2.6.5 and 2.6.6-rc1.

From my test logs:
-----------------------

Linux petpc1 2.6.5 #1 SMP Sun Sep 12 17:16:05 CDT 2004 i686 i686 i386 GNU/Linux

/data/work3/multishot2 ext2 performance numbers include fsync : 6.690 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 7.978 sec; 64.176 MB/s 13.63 % full performance numbers include fsync : 0.188 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 8.118 sec; 63.067 MB/s 13.63 % full ext3 performance numbers include fsync : 6.541 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 9.015 sec; 56.794 MB/s 14.48 % full performance numbers include fsync : 0.003 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 7.815 sec; 65.513 MB/s 14.48 % full xfs performance numbers include fsync : 6.539 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 7.740 sec; 66.147 MB/s 13.44 % full performance numbers include fsync : 0.000 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 7.278 sec; 70.353 MB/s 13.44 % full jfs performance numbers include fsync : 6.517 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 8.016 sec; 63.871 MB/s 13.47 % full performance numbers include fsync : 0.000 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 7.455 sec; 68.677 MB/s 13.47 % full reiserfs performance numbers include fsync : 7.412 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 8.798 sec; 58.195 MB/s 14.26 % full performance numbers include fsync : 0.004 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 50.301 sec; 10.179 MB/s 14.26 % full


Linux petpc1 2.6.6-rc1 #1 SMP Sun Sep 12 17:25:40 CDT 2004 i686 i686 i386 
GNU/Linux

/data/work3/multishot2 ext2 performance numbers include fsync : 6.570 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 7.849 sec; 65.229 MB/s 13.63 % full performance numbers include fsync : 0.178 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 7.998 sec; 64.016 MB/s 13.63 % full ext3 performance numbers include fsync : 6.364 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 8.704 sec; 58.820 MB/s 14.48 % full performance numbers include fsync : 0.003 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 7.848 sec; 65.239 MB/s 14.48 % full xfs performance numbers include fsync : 6.484 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 7.723 sec; 66.292 MB/s 13.44 % full performance numbers include fsync : 0.000 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 8.532 sec; 60.012 MB/s 13.44 % full jfs performance numbers include fsync : 6.496 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 8.006 sec; 63.950 MB/s 13.47 % full performance numbers include fsync : 0.008 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 7.480 sec; 68.446 MB/s 13.47 % full reiserfs performance numbers include fsync : 6.913 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 8.362 sec; 61.226 MB/s 14.26 % full performance numbers include fsync : 0.004 sec wrote 512.000 MB in 16 writes, 32.000 MB/write, 128.183 sec; 3.994 MB/s 14.26 % full

It looks like there were 9 "bk" releases between 2.6.5 and 2.6.6-rc1. I will continue to try to narrow down exactly where the change happened (unless you have specific versions that you would like me to try first).

Thanks,

Jim Foris


Thanks again,

Jim Foris


thanks.

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Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, Nathan Scott Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, James Foris Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, James Foris <= Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, James Foris Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, James Foris Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, Nathan Scott Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, James Foris Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, Steve Lord Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, James Foris Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, Nathan Scott Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, Nathan Scott Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, James Foris Re: XFS performance issues: O_DIRECT and Linux 2.6.6+, Nathan Scott

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