From: Andi Kleen <andi@firstfloor.org>
To: Ben Gamari <bgamari.foss@gmail.com>
Cc: Avi Kivity <avi@redhat.com>,
linux-btrfs@vger.kernel.org, Andi Kleen <andi@firstfloor.org>,
Arjan van de Ven <arjan@infradead.org>,
linux-kernel@vger.kernel.org, tytso@mit.edu, npiggin@suse.de,
mingo@elte.hu, Ruald Andreae <ruald.a@gmail.com>,
Jens Axboe <jens.axboe@oracle.com>, Olly Betts <olly@survex.com>,
martin f krafft <madduck@madduck.net>
Subject: Re: Poor interactive performance with I/O loads with fsync()ing
Date: Sun, 11 Apr 2010 19:20:07 +0200 [thread overview]
Message-ID: <20100411172007.GA11514@basil.fritz.box> (raw)
In-Reply-To: <4bc1fa59.c5c2f10a.776d.ffffcd91@mx.google.com>
> Has the reason for this been identified? Judging from the nature of metadata
> loads, it would seem that it should be substantially easier to implement
> fsync() efficiently.
By design a copy on write tree fs would need to flush a whole
tree hierarchy on a sync. btrfs avoids this by using a special
log for fsync, but that causes more overhead if you have that
log on the same disk. So IO subsystem will do more work.
It's a bit like JBD data journaling.
However it should not have the stalls inherent in ext3's journaling.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-04-11 17:20 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-16 15:31 Poor interactive performance with I/O loads with fsync()ing Ben Gamari
2010-03-17 1:24 ` tytso
2010-03-17 3:18 ` Ben Gamari
2010-03-17 3:30 ` tytso
2010-03-17 4:31 ` Ben Gamari
2010-03-26 3:16 ` Ben Gamari
2010-03-17 4:53 ` Nick Piggin
2010-03-17 9:37 ` Ingo Molnar
2010-03-26 3:31 ` Ben Gamari
2010-04-09 15:21 ` Ben Gamari
2010-03-26 3:28 ` Ben Gamari
2010-03-23 19:51 ` Jesper Krogh
2010-03-26 3:13 ` Ben Gamari
2010-03-28 1:20 ` Ben Gamari
2010-03-28 1:29 ` Ben Gamari
2010-03-28 3:42 ` Arjan van de Ven
2010-03-28 14:06 ` Ben Gamari
2010-03-28 22:08 ` Andi Kleen
2010-04-09 14:56 ` Ben Gamari
2010-04-11 15:03 ` Avi Kivity
2010-04-11 16:35 ` Ben Gamari
2010-04-11 17:20 ` Andi Kleen [this message]
2010-04-11 18:16 ` Thomas Gleixner
2010-04-11 18:42 ` Andi Kleen
2010-04-11 21:54 ` Thomas Gleixner
2010-04-11 23:43 ` Hans-Peter Jansen
2010-04-12 0:22 ` Dave Chinner
2010-04-14 18:40 ` Ric Wheeler
-- strict thread matches above, loose matches on Subject: below --
2010-03-23 11:28 Pawel S
2010-03-23 13:27 ` Jens Axboe
2010-03-26 3:35 ` Ben Gamari
2010-03-30 10:46 ` Pawel S
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