From: Johannes Stezenbach <js@sig21.net>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: arnd@arndb.de, ebiederm@xmission.com, gnomes@lxorguk.ukuu.org.uk,
teg@jklm.no, jkosina@suse.cz, luto@amacapital.net,
linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
daniel@zonque.or, dh.herrmann@gmail.com, tixxdz@opendz.org
Subject: Re: [PATCH v3 00/13] Add kdbus implementation
Date: Mon, 19 Jan 2015 19:06:42 +0100 [thread overview]
Message-ID: <20150119180642.GA27957@sig21.net> (raw)
In-Reply-To: <1421435777-25306-1-git-send-email-gregkh@linuxfoundation.org>
Hi Greg and Daniel,
I don't have a clue so I need to ask some stupid questions...
On Fri, Jan 16, 2015 at 11:16:04AM -0800, Greg Kroah-Hartman wrote:
> kdbus is a kernel-level IPC implementation that aims for resemblance to
> the the protocol layer with the existing userspace D-Bus daemon while
> enabling some features that couldn't be implemented before in userspace.
>
> The documentation in the first patch in this series explains the
> protocol and the API details.
How about the big picture?
> Reasons why this should be done in the kernel, instead of userspace as
> it is currently done today include the following:
[abbreviated]
> - performance
> - security
> - semantics for apps with heavy data payloads
First of all I wonder about the relationship with D-Bus.
http://dbus.freedesktop.org/doc/dbus-specification.html says:
D-Bus is designed for two specific use cases:
A "system bus" for notifications from the system to user
sessions, and to allow the system to request input from
user sessions.
A "session bus" used to implement desktop environments such
as GNOME and KDE.
D-Bus is not intended to be a generic IPC system for any
possible application, and intentionally omits many features
found in other IPC systems for this reason.
Does this also apply to kdbus? If not, what are the
suggested uses of kdbus beyond those where D-Bus is
currently used?
Another related quote by Havoc Pennington:
http://lists.freedesktop.org/archives/dbus/2012-March/015024.html
In general, reading this, I think in some cases there are
problems that make sense to fix in dbus, and in other cases
there are problems that are best solved by not using dbus.
...
there are about 10000 IPC solutions already, from ICE (both of
them) to ZeroMQ to AMQP to CORBA to X11 to HTTP to SOAP to
WebSockets to SUN-RPC to whatever-the-heck. To me, trying to
make dbus configurable so that it can substitute for any of
these is a Bad Idea (tm).
Do you think it also applies to kdbus?
Wrt the performance improvement achieved by kdbus, my impression
about D-Bus is that the number of messages on my system is
about a dozen per minute. Are there actually any existing
applications using D-Bus that have a performance issue?
Or is this only about future possible uses?
Linked from http://kroah.com/log/blog/2014/01/15/kdbus-details/,
http://lwn.net/Articles/580194/ "The unveiling of kdbus" says:
Unlike most other kernels, Linux has never had a well-designed
IPC mechanism. Windows and Mac OS have this feature; even
Android, based on Linux, has one in the form of the "binder"
subsystem. Linux, instead, has only had the primitives —
sockets, FIFOs, and shared memory — but those have never been
knitted together into a reasonable application-level API. Kdbus
is an attempt to do that knitting and create something that is
at least as good as the mechanisms found on other systems.
These are bold words. I'm not sure what Windows and Mac OS
have in terms of IPC, but the above suggests that kdbus
is *the* new Linux IPC that everyone will use for everything,
rather than a special purpose facility.
True?
Thanks,
Johannes
next prev parent reply other threads:[~2015-01-19 18:31 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-16 19:16 [PATCH v3 00/13] Add kdbus implementation Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 01/13] kdbus: add documentation Greg Kroah-Hartman
2015-01-20 13:53 ` Michael Kerrisk (man-pages)
2015-01-20 14:31 ` David Herrmann
2015-01-20 14:42 ` Josh Boyer
2015-01-20 14:53 ` Djalal Harouni
2015-01-20 16:08 ` Johannes Stezenbach
2015-01-20 17:00 ` David Herrmann
2015-01-20 22:00 ` Johannes Stezenbach
2015-01-21 10:28 ` Michael Kerrisk (man-pages)
2015-01-20 18:23 ` Daniel Mack
2015-01-21 10:32 ` Michael Kerrisk (man-pages)
2015-01-21 15:19 ` Theodore Ts'o
2015-01-21 16:58 ` Daniel Mack
2015-01-22 10:18 ` Michael Kerrisk (man-pages)
2015-01-22 13:46 ` David Herrmann
2015-01-22 14:49 ` Austin S Hemmelgarn
2015-01-23 16:08 ` Greg Kroah-Hartman
2015-01-26 14:46 ` Michael Kerrisk (man-pages)
2015-01-27 15:05 ` David Herrmann
2015-01-27 16:03 ` Andy Lutomirski
2015-01-29 8:53 ` Daniel Mack
2015-01-29 11:25 ` Andy Lutomirski
2015-01-29 11:42 ` Daniel Mack
2015-01-29 12:09 ` Andy Lutomirski
2015-02-02 9:34 ` Daniel Mack
2015-02-02 20:12 ` Andy Lutomirski
2015-02-03 10:09 ` Daniel Mack
2015-02-04 0:41 ` Andy Lutomirski
2015-02-04 2:47 ` Eric W. Biederman
2015-02-04 3:14 ` Greg Kroah-Hartman
2015-02-04 6:30 ` Eric W. Biederman
2015-02-04 23:03 ` Andy Lutomirski
2015-02-05 0:16 ` David Herrmann
2015-02-08 16:54 ` Andy Lutomirski
2015-01-27 18:03 ` Michael Kerrisk (man-pages)
2015-01-23 11:47 ` Michael Kerrisk (man-pages)
2015-01-23 15:54 ` Greg Kroah-Hartman
2015-01-26 14:42 ` Michael Kerrisk (man-pages)
2015-01-26 15:26 ` Tom Gundersen
2015-01-26 16:44 ` christoph Hellwig
2015-01-26 16:45 ` Michael Kerrisk (man-pages)
2015-01-27 15:23 ` David Herrmann
2015-01-27 17:53 ` Michael Kerrisk (man-pages)
2015-01-27 18:14 ` Daniel Mack
2015-01-28 10:46 ` Michael Kerrisk (man-pages)
2015-01-20 13:58 ` Michael Kerrisk (man-pages)
2015-01-20 17:50 ` Daniel Mack
2015-01-21 8:57 ` Michael Kerrisk (man-pages)
2015-01-21 9:07 ` Daniel Mack
2015-01-21 9:07 ` Michael Kerrisk (man-pages)
2015-01-21 9:12 ` Daniel Mack
2015-01-23 6:28 ` Ahmed S. Darwish
2015-01-23 13:19 ` Greg Kroah-Hartman
2015-01-23 13:29 ` Greg Kroah-Hartman
2015-01-25 3:30 ` Ahmed S. Darwish
2015-01-16 19:16 ` [PATCH 02/13] kdbus: add header file Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 03/13] kdbus: add driver skeleton, ioctl entry points and utility functions Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 04/13] kdbus: add connection pool implementation Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 05/13] kdbus: add connection, queue handling and message validation code Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 06/13] kdbus: add node and filesystem implementation Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 07/13] kdbus: add code to gather metadata Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 08/13] kdbus: add code for notifications and matches Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 09/13] kdbus: add code for buses, domains and endpoints Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 10/13] kdbus: add name registry implementation Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 11/13] kdbus: add policy database implementation Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 12/13] kdbus: add Makefile, Kconfig and MAINTAINERS entry Greg Kroah-Hartman
2015-01-16 19:16 ` [PATCH 13/13] kdbus: add selftests Greg Kroah-Hartman
2015-01-16 22:07 ` [PATCH v3 00/13] Add kdbus implementation Josh Boyer
2015-01-16 22:18 ` Greg Kroah-Hartman
2015-01-17 0:26 ` Daniel Mack
2015-01-17 0:41 ` Josh Boyer
2015-01-19 18:06 ` Johannes Stezenbach [this message]
2015-01-19 18:38 ` Greg Kroah-Hartman
2015-01-19 20:19 ` Johannes Stezenbach
2015-01-19 20:31 ` Greg Kroah-Hartman
2015-01-19 23:38 ` Johannes Stezenbach
2015-01-20 1:13 ` Greg Kroah-Hartman
2015-01-20 10:57 ` Johannes Stezenbach
2015-01-20 11:26 ` Greg Kroah-Hartman
2015-01-20 13:24 ` Johannes Stezenbach
2015-01-20 14:12 ` Michael Kerrisk (man-pages)
2015-01-26 21:32 ` One Thousand Gnomes
2015-01-19 18:33 ` Johannes Stezenbach
2015-01-20 14:05 ` Michael Kerrisk (man-pages)
2015-01-20 14:15 ` Michael Kerrisk (man-pages)
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