parallel message processing (Python)

[Pavel Strashkin]

Hi Thom,

You must use async requests dispatching. Take a look closer to help
for dbus.service.method, there you'll find info about async_callbacks
keyword argument. I wrote an example to you:
http://pastebin.com/ExBRViAJ
It works really well to me long time.

2011/1/22 Thom Nichols <tmnichols at gmail.com>:
> Hello DBus community,
>
> We've been enjoying DBus as an IPC mechanism in Python for some time now,
> however we've recently experienced a wrinkle which I think is related to how
> incoming DBus messages are dispatched.
>
> In short, all DBus messages appear to be handled serially within the same
> process, even though threads are using private connections.  If a dbus
> method call takes a long time to return (i.e. a python function annotated
> with dbus.service.method or signal,) it prevents any concurrent messages
> (and I suspect outgoing dbus calls) from being processed.
>
> Is there any way this can be changed to something more like a thread pool so
> that multiple dbus messages can be handled in parallel?  Particularly
> messages to different services should not interfere with each other.  I'm
> not averse to coding it myself, but I'm looking for input as to whether or
> not it might be possible from an architectural standpoint.
>
> Certainly we can get around the problem by making all of our remote methods
> and signal handlers immediately dispatch work to a thread or thread pool (so
> that the dbus handler returns quickly,) but that won't work for synchronous
> dbus method calls.  Certainly that also adds some code overhead that I'd
> like to solve at a lower level if possible.
>
> Attached is a script that demonstrates the problem.  (Also here:
> http://pastebin.com/4mTh4Q9Y )  Certainly this script is running as a single
> process which seems to defeat the point of IPC, but the concept (and
> underlying issue) is still present regardless I believe.
>
> Thanks in advance for any input.
>
> -Thom
>
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