[prev in list] [next in list] [prev in thread] [next in thread] 

List:       freedesktop-dbus
Subject:    Re: kdbus, bus1 and systemd/non-linux hosts
From:       "Thomas Kluyver" <thomas () kluyver ! me ! uk>
Date:       2023-04-11 9:21:18
Message-ID: f0a20bbc-805f-42dc-82f3-280bb771d774 () app ! fastmail ! com
[Download RAW message or body]

Hi René,

This seems like a confusing request, at least to me. You start off talking about \
mechanisms that were meant to be part of the Linux kernel, but then you ask for \
cross-platform solutions. A messaging system built on sockets, like D-Bus, can be \
cross-platform much more easily than something built on a Linux-specific kernel \
feature. And D-Bus does work on Mac and Windows, although some of its features \
(passing file descriptors) aren't available on Windows.

FWIW, it looks like bus1 got shelved as well, at least adding it to the regular Linux \
kernel - development and discussion seem to dry up around 2016-17. It sounds like \
people found it was possible to write a higher-performance D-Bus message bus even \
without new kernel features, and this is where dbus-broker comes from.

> Part of my interest comes from the fact that I tend to work on \
> old/cheap/underdimensioned systems that I probably ask a bit much of. There are \
> times where a heavy dbus client like kmail becomes very sluggish, waiting for \
> something that probably involves dbus communication while there isn't a clear CPU \
> hogger.

Have you actually figured out that D-Bus itself is causing the slowness, and not \
whatever KMail is talking D-Bus to? Or is that a guess? It's *really* hard to guess \
correctly about performance in complex systems, so chasing ways to make D-Bus faster \
might well be a waste of time.

> I noticed that the dbus-daemon has a single-threaded design and cannot help but \
> wonder if that's still by definition the best approach these days.

Your old/cheap systems probably wouldn't see much, if any, benefit from a \
multithreaded dbus-daemon. Though that's a guess too. ;-)

Best wishes,
Thomas

On Sun, 9 Apr 2023, at 11:09, René J.V. Bertin wrote:
> Hi,
> 
> Here is maybe not the best place to ask, but I've come across the 
> apparently dfunct kdbus project and its supposed successor, bus1. The 
> idea of using a kernel interface instead of a handling everything in 
> userspace makes a lot of sense if you consider the demonstrated 
> performance gains. They are all the more interesting to me as I'm a 
> KMail user, where potentially lots of data gets transported over the 
> d-bus.
> 
> I've avoided kdbus for now but its successor (bus1-broker) turns out to 
> depend on systemd which makes it a no-go for me. Are there any similar 
> alternatives that don't have this dependency?
> Also, are you aware of comparable implementations for Mac or MS Win, 
> using the kernel mechanisms that exist there? (A quick glance suggests 
> Apple's XPC architecture might even be rich enough to act as a conduit, 
> possibly combined with GCD?)
> 
> Mostly just curious as I have almost no programming experience with 
> either of these technologies.
> 
> R.


[prev in list] [next in list] [prev in thread] [next in thread]