From: Andy Lutomirski <luto@amacapital.net>
To: Jan Kara <jack@suse.cz>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
Dave Chinner <david@fromorbit.com>,
"Theodore Ts'o" <tytso@mit.edu>,
Dave Hansen <dave.hansen@linux.intel.com>,
xfs@oss.sgi.com, Tim Chen <tim.c.chen@linux.intel.com>,
Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH v3 0/5] Rework mtime and ctime updates on mmaped writes
Date: Wed, 4 Sep 2013 10:33:22 -0700 [thread overview]
Message-ID: <CALCETrVayD1P2a8ShjZ2e4HYGwL_yE8FM7GnrWaL9MgXYMGvHg@mail.gmail.com> (raw)
In-Reply-To: <20130904150854.GF3996@quack.suse.cz>
On Wed, Sep 4, 2013 at 8:08 AM, Jan Kara <jack@suse.cz> wrote:
> 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...
Will do, although the data from my workload will be a little strange.
I was hoping that Dave Hansen would re-run his benchmark with these
patches applied. I tried to run it, but it wasn't obvious what the
numbers that spewed out meant.
--Andy
>
> Honza
> --
> Jan Kara <jack@suse.cz>
> SUSE Labs, CR
--
Andy Lutomirski
AMA Capital Management, LLC
prev parent reply other threads:[~2013-09-04 17:33 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
2013-09-04 17:33 ` Andy Lutomirski [this message]
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