All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jack Wang <jinpu.wang-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
To: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org
Cc: dongsu.park-EIkl63zCoXaH+58JC4qpiA@public.gmane.org
Subject: bcache strange behaviour in write back mode
Date: Mon, 22 Apr 2013 21:15:14 +0200	[thread overview]
Message-ID: <51758C42.4040708@profitbricks.com> (raw)

Hi all,

We've seen strange behaviour in bcache mode in current bcache-testing
branch with Possible allocator fix:

Once I start writing data with "dd if=/dev/zero of=/dev/bcache0 bs=4k
count=10000 oflag=sync", all SSDs in the Pool go close to 100% util and
I see about 3600 writes/second in iostat for each disk in the pool, BUT
no data written in means of throughput.

Then after some seconds (the flush interval of bcache) I see the flush
of the writeback and also data written to the pool SSDs which looks
pretty much like reordering and merging happened for that data.

bcache-3.2 does not have such problem.
only bcache(master) and bcache-testing have such problem.

What's the possible reason?

Regards,
Jack

             reply	other threads:[~2013-04-22 19:15 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-22 19:15 Jack Wang [this message]
     [not found] ` <CAC7rs0u=epPv0c_swBSifi_fDRC0k9WpZ+34OmFdgxjR3-8WcA@mail.gmail.com>
     [not found]   ` <CAC7rs0u=epPv0c_swBSifi_fDRC0k9WpZ+34OmFdgxjR3-8WcA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-04-22 20:27     ` bcache strange behaviour in write back mode Jack Wang
     [not found]       ` <51759D17.5040204-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
2013-04-22 21:51         ` Kent Overstreet
     [not found]           ` <20130422215138.GA9931-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2013-04-23 11:56             ` Jack Wang
     [not found]               ` <517676E7.4030805-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
2013-04-23 18:40                 ` Kent Overstreet
     [not found]                   ` <CAH+dOxL9Ajsp7fruw-9nC63rJLzOqBYreeE1URxF945-pv6vug-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-04-24  6:56                     ` Jack Wang
     [not found] ` <51758C42.4040708-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
2013-04-22 20:26   ` Kent Overstreet
2013-04-24 19:49   ` Jack Wang
     [not found]     ` <51783733.9080907-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
2013-04-24 20:13       ` Kent Overstreet
     [not found]         ` <CAC7rs0s-_e1WaymU1OcuBv+Tf8hiJLED=m5Qrpxhar6Zk3H9uQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-04-24 20:29           ` Jack Wang

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=51758C42.4040708@profitbricks.com \
    --to=jinpu.wang-eikl63zcoxah+58jc4qpia@public.gmane.org \
    --cc=dongsu.park-EIkl63zCoXaH+58JC4qpiA@public.gmane.org \
    --cc=koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org \
    --cc=linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.