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From: Jan Kara <jack@suse.cz>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Theodore Ts'o <tytso@mit.edu>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	linux-kernel@vger.kernel.org, xfs@oss.sgi.com,
	Christoph Hellwig <hch@infradead.org>, Jan Kara <jack@suse.cz>,
	linux-ext4@vger.kernel.org, Tim Chen <tim.c.chen@linux.intel.com>
Subject: Re: [PATCH v3 0/5] Rework mtime and ctime updates on mmaped writes
Date: Wed, 4 Sep 2013 17:08:54 +0200	[thread overview]
Message-ID: <20130904150854.GF3996@quack.suse.cz> (raw)
In-Reply-To: <cover.1377193658.git.luto@amacapital.net>

On Thu 22-08-13 17:03:16, Andy Lutomirski wrote:
> Writes via mmap currently update mtime and ctime in ->page_mkwrite.
> This hurts both throughput and latency.  In workloads that dirty a
> large number of mmapped pages, ->page_mkwrite can be hot and
> file_update_time is slow and scales poorly.  Updating timestamps can
> also sleep, which hurts latency for real-time workloads.
  It would help to make your case if you posted the latency comparison
before & after the patchset in this introductory email. We can then see
how significant is the reduction of latency...

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

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  parent reply	other threads:[~2013-09-04 15:08 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-23  0:03 [PATCH v3 0/5] Rework mtime and ctime updates on mmaped writes Andy Lutomirski
2013-08-23  0:03 ` [PATCH v4 1/7] mm: Track mappings that have been written via ptes Andy Lutomirski
2013-08-23  0:03 ` [PATCH v4 2/7] fs: Add inode_update_time_writable Andy Lutomirski
2013-08-23  0:03 ` [PATCH v4 3/7] mm: Allow filesystems to defer cmtime updates Andy Lutomirski
2013-09-04 14:57   ` Jan Kara
2013-09-04 17:54     ` Andy Lutomirski
2013-09-04 19:20       ` Jan Kara
2013-09-04 20:05         ` Andy Lutomirski
2013-08-23  0:03 ` [PATCH v4 4/7] mm: Scan for dirty ptes and update cmtime on MS_ASYNC Andy Lutomirski
2013-08-23  0:03 ` [PATCH v4 5/7] ext4: Defer mmap cmtime updates Andy Lutomirski
2013-08-23  0:03 ` [PATCH v4 6/7] btrfs: " Andy Lutomirski
2013-08-23  0:03 ` [PATCH v4 7/7] xfs: " Andy Lutomirski
2013-08-23  1:12 ` [PATCH v3 0/5] Rework mtime and ctime updates on mmaped writes Andy Lutomirski
2013-09-04 14:06 ` Jan Kara
2013-09-04 15:08 ` Jan Kara [this message]
2013-09-04 17:33   ` Andy Lutomirski

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