All of lore.kernel.org
 help / color / mirror / Atom feed
From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: sagi@grimberg.me, linux-nvme@lists.infradead.org,
	Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>,
	hch@lst.de
Subject: Re: [PATCH] nvmet: allow block device to use buffered I/O
Date: Thu, 31 Oct 2019 15:42:47 +0100	[thread overview]
Message-ID: <20191031144247.GA6024@lst.de> (raw)
In-Reply-To: <20191030063609.GB16863@redsun51.ssa.fujisawa.hgst.com>

On Wed, Oct 30, 2019 at 03:36:09PM +0900, Keith Busch wrote:
> On Tue, Oct 29, 2019 at 09:26:23PM -0700, Chaitanya Kulkarni wrote:
> > NVMeOF target already has a support to execute requests in the
> > buffered I/O mode with file backend. This patch allows block devices
> > to be used with file backend code so that buffered I/O parameter can
> > be set for a block device backed namespace when newly introduce
> > configfs parameter use_vfs=1.
> 
> Is the fs overhead so bad that we can't just remove the bio based nvme
> target? It seems low enough that having a single path to optimize is
> worth considering.

Once we go down bemchmarketing for latency and iops it matters, as it
is significantly less code and cachelines.  The actual I/O pattern is
the same, so for more usual setups that do bigger I/O or have slower
devices they'll be mostly the same.

_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  reply	other threads:[~2019-10-31 14:43 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-30  4:26 [PATCH] nvmet: allow block device to use buffered I/O Chaitanya Kulkarni
2019-10-30  6:36 ` Keith Busch
2019-10-31 14:42   ` Christoph Hellwig [this message]
2019-10-31 14:45 ` Christoph Hellwig
2019-11-01  6:35   ` Chaitanya Kulkarni
2019-10-31 16:30 ` Sagi Grimberg

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=20191031144247.GA6024@lst.de \
    --to=hch@lst.de \
    --cc=chaitanya.kulkarni@wdc.com \
    --cc=kbusch@kernel.org \
    --cc=linux-nvme@lists.infradead.org \
    --cc=sagi@grimberg.me \
    /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.