[systemd-devel] KDBus Signals and Timeouts

Justin Brown justin.brown at fandingo.org
Tue Feb 25 12:18:57 PST 2014

On Tue, Feb 25, 2014 at 12:12 PM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Tue, 25.02.14 10:41, Justin Brown (justin.brown at fandingo.org) wrote:
> And broadcast signals should never be large datagrams, but
> only very short.

Could you elaborate on this point? One of the major points of emphasis
with kdbus seems to be performance. Why is that restricted to method
calls? I understand that there would be implementation complexities in
multiplexing memfds to all of the signal subscribers, but it seems
like a desirable feature. A single source application that sends
relatively large amounts of data (a few KB up to possibly several GB)
to several third-party sinks seems like a natural use of memfds.

As far as I can tell, the only way to accomplish this with kdbus would
be for the source application to have a subscribe() method, so it
could send methods to each sink. I apologize for asking such a
simplistic question (I don't have my kdbus VM up and running yet.),
but if I were to take this route, can the same memfd be used in
multiple methods or would a new one need to be created for each


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