From: Wu Fengguang <fengguang.wu@intel.com>
To: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@infradead.org>
Subject: Re: NFS page states & writeback
Date: Fri, 25 Mar 2011 22:32:29 +0800 [thread overview]
Message-ID: <20110325143229.GA12875@localhost> (raw)
In-Reply-To: <20110325142253.GA11589@localhost>
> However there is another problem. Look at the below graph. Even though
> the commits are sent to NFS server in relatively small size and evenly
> distributed in time (the green points), the commit COMPLETION events
> from the server are observed to be pretty bumpy over time (the blue
> points sitting on the red lines). This may not be easily fixable.. So
> we still have to live with bumpy NFS commit completions...
>
> http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v6/NFS/nfs-1dd-1M-8p-2945M-20%25-2.6.38-rc6-dt6+-2011-02-22-21-09/nfs-commit.png
The bumpy commit completions result in large fluctuations in estimated
write bandwidth (the red line):
http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v6/NFS/nfs-1dd-1M-8p-2945M-20%25-2.6.38-rc6-dt6+-2011-02-22-21-09/balance_dirty_pages-bandwidth.png
and fluctuated number of dirty pages (the red line):
http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v6/NFS/nfs-1dd-1M-8p-2945M-20%25-2.6.38-rc6-dt6+-2011-02-22-21-09/balance_dirty_pages-pages.png
And you can see the v6 patches still manages to keep the pause times
(the red points) under 100ms (hands down!):
http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v6/NFS/nfs-1dd-1M-8p-2945M-20%25-2.6.38-rc6-dt6+-2011-02-22-21-09/balance_dirty_pages-pause.png
Thanks,
Fengguang
next prev parent reply other threads:[~2011-03-25 14:32 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-25 1:28 NFS page states & writeback Jan Kara
2011-03-25 4:47 ` Dave Chinner
2011-03-25 7:11 ` Wu Fengguang
2011-03-25 22:24 ` Jan Kara
[not found] ` <20110325222458.GB26932-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
2011-03-25 23:04 ` Dave Chinner
2011-03-25 7:00 ` Wu Fengguang
2011-03-25 9:39 ` Dave Chinner
2011-03-25 14:22 ` Wu Fengguang
2011-03-25 14:32 ` Wu Fengguang [this message]
2011-03-25 18:26 ` Jan Kara
2011-03-25 22:55 ` Dave Chinner
2011-03-25 23:24 ` Jan Kara
2011-03-26 1:18 ` Dave Chinner
2011-03-27 15:26 ` Trond Myklebust
[not found] ` <1301239601.22136.23.camel-SyLVLa/KEI9HwK5hSS5vWB2eb7JE58TQ@public.gmane.org>
2011-03-28 0:23 ` Dave Chinner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110325143229.GA12875@localhost \
--to=fengguang.wu@intel.com \
--cc=akpm@linux-foundation.org \
--cc=david@fromorbit.com \
--cc=hch@infradead.org \
--cc=jack@suse.cz \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-nfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).