[systemd-devel] sd-bus vs gdbus on dbus-daemon

[Simon McVittie]

On 29/04/15 16:49, Greg KH wrote:
> I'll echo Simon's statement here, making a call to
> g_dbus_proxy_call_sync() seems like an odd thing to test.  Is this
> really how your application wants to work?  Is it the normal call path
> that you need optimized?

To be completely clear here: I am not saying that GDBusProxy is an
unusual thing for an application to be using - far from it, it is a
convenient high-level API that can cover a lot of use-cases, and if I
wanted to write code to (say) manipulate systemd's D-Bus interfaces,
it's what I'd use.

What I *am* saying is that GDBusProxy is nowhere near the "performance"
end of the performance/convenience trade-off, either in general, among
D-Bus implementations specifically, or even within GDBus - which makes
it an odd thing to benchmark. If it shows up as a significant impact in
your profiling, then that might well indicate that you're using the
wrong tool for the job.

An analogy: suppose you told me you were interested in switching from
some Python code that constructs MIME emails to some C code that does
the same, because you need to send patches to systemd-devel faster.
Instead of worrying about how efficiently-implemented those MIME modules
were, I'd be asking you why (and whether) you are sending enough patches
that it makes any practical difference, and if you are, whether pushing
them to a git repository might make more sense :-)

-- 
Simon McVittie
Collabora Ltd. <http://www.collabora.com/>