public inbox for [email protected]
 help / color / mirror / Atom feed
From: Ming Lei <[email protected]>
To: Jens Axboe <[email protected]>
Cc: [email protected], [email protected],
	[email protected], [email protected],
	[email protected]
Subject: Re: ublk-nbd: ublk-nbd is avaialbe
Date: Thu, 26 Jan 2023 11:08:26 +0800	[thread overview]
Message-ID: <Y9Huqg9HeU3+Ki1H@T590> (raw)
In-Reply-To: <[email protected]>

Hi Jens,

On Thu, Jan 19, 2023 at 11:49:04AM -0700, Jens Axboe wrote:
> On 1/19/23 7:23 AM, Ming Lei wrote:
> > Hi,
> > 
> > ublk-nbd[1] is available now.
> > 
> > Basically it is one nbd client, but totally implemented in userspace,
> > and wrt. current nbd-client in [2], the transmission phase is done
> > by linux block nbd driver.
> > 
> > The handshake implementation is borrowed from nbd project[2], so
> > basically ublk-nbd just adds new code for implementing transmission
> > phase, and it can be thought as moving linux block nbd driver into
> > userspace.
> > 
> > The added new code is basically in nbd/tgt_nbd.cpp, and io handling
> > is based on liburing[3], and implemented by c++20 coroutine, so
> > everything is done in single pthread totally lockless, meantime turns
> > out it is pretty easy to design & implement, attributed to ublk framework,
> > c++20 coroutine and liburing.
> > 
> > ublk-nbd supports both tcp and unix socket, and allows to enable io_uring
> > send zero copy via command line '--send_zc', see details in README[4].
> > 
> > No regression is found in xfstests by using ublk-nbd as both test device
> > and scratch device, and builtin test(make test T=nbd) runs well.
> > 
> > Fio test("make test T=nbd") shows that ublk-nbd performance is
> > basically same with nbd-client/nbd driver when running fio on real
> > ethernet link(1g, 10+g), but ublk-nbd IOPS is higher by ~40% than
> > nbd-client(nbd driver) with 512K BS, which is because linux nbd
> > driver sets max_sectors_kb as 64KB at default.
> > 
> > But when running fio over local tcp socket, it is observed in my test
> > machine that ublk-nbd performs better than nbd-client/nbd driver,
> > especially with 2 queue/2 jobs, and the gap could be 10% ~ 30%
> > according to different block size.
> 
> This is pretty nice! Just curious, have you tried setting up your
> ring with
> 
> p.flags |= IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN;
> 
> and see if that yields any extra performance improvements for you?
> Depending on how you do processing, you should not need to do any
> further changes there.
> 
> A "lighter" version is just setting IORING_SETUP_COOP_TASKRUN.

IORING_SETUP_COOP_TASKRUN is enabled in current ublksrv.

After disabling COOP_TASKRUN and enabling SINGLE_ISSUER & DEFER_TASKRUN,
not see obvious improvement, meantime regression is observed on 64k
rw.


Thanks,
Ming


  reply	other threads:[~2023-01-26  3:09 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-19 14:23 ublk-nbd: ublk-nbd is avaialbe Ming Lei
2023-01-19 18:49 ` Jens Axboe
2023-01-26  3:08   ` Ming Lei [this message]
2023-01-26  4:08     ` Willy Tarreau
2023-01-26 11:41       ` Ming Lei
2023-01-26 12:54         ` Willy Tarreau
2023-02-28 10:04 ` Pavel Machek
2023-03-02  3:11   ` Ming Lei
2023-03-11 13:21 ` Wouter Verhelst
2023-03-12  8:30   ` Ming Lei

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=Y9Huqg9HeU3+Ki1H@T590 \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /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