Re: [PATCH 01/13] kdbus: add documentation

Hi all,

On Tue, Jan 20, 2015 at 03:53:53PM +0100, Djalal Harouni wrote:

On Tue, Jan 20, 2015 at 09:42:59AM -0500, Josh Boyer wrote:

quoted

On Tue, Jan 20, 2015 at 9:31 AM, David Herrmann [off-list ref] wrote:

quoted

If you run a 3.18 kernel, you can install kdbus.ko from our repository
and boot a full Fedora system running Gnome3 with kdbus, given that
you compiled systemd with --enable-kdbus (which is still
experimental). No legacy dbus1 daemon is running. Instead, we have a
bus-proxy that converts classic dbus1 to kdbus, so all
bus-communication runs on kdbus.

FWIW, we've been building a "playground" repository for the kernel
that contains this already for Fedora.  If you have a stock Fedora 21
or rawhide install, you can use:

https://copr.fedoraproject.org/coprs/jwboyer/kernel-playground/

which has the kernel+kdbus and systemd built with --enable-kdbus
already.  Easy enough to throw in a VM for testing.

Another addition, if kdbus is installed and loaded, you could also use
systemd-nspawn to boot a full system (systemd compiled with
--enable-kdbus) in a container [1], kdbusfs will be mounted in the
container.

There is also the busctl tool to query kdbus...

http://www.freedesktop.org/wiki/Software/systemd/VirtualizedTesting/

It is reassuring that kdbus actually works :)

However, let me repeat and rephrase my previous questions:
Is there a noticable or measurable improvement from using kdbus?
IOW, is the added complexity of kdbus worth the result?

I have stated my believe that current usage of D-Bus is not
performance sensitive and the number of messages exchanged
is low.  I would love it if you would prove me wrong.
Or if you could show that any D-Bus related bug in Gnome3
is fixed by kdbus.

I would sooo love it if someone would finally post some
data that proves kdbus is useful beyond systemd.


Thanks,
Johannes