[ros-users] Nodelets

[Josh Faust]

>
>
> In general, nodelets should not be abused. If the performance of nodes
> (copy/(de)serialization) is really what's
> dragging your processing graph down, then sure, nodelets are offering a
> viable alternative. However, this should really
> be profiled first for each application.
>
>
This isn't entirely true.  Adding processes also means adding threads, which
increases context switches/etc.  Having everything in a single process means
more control over everything.  There's a reason game consoles run a single
process, and that process generally has # threads == # cores.  I think in
the "ideal" world everything that can be a nodelet should be, and a
fully-debugged application would be a single process running many nodelets.
 In practice there are likely exceptions (like, say, GUI applications), but
overall I think it's a reasonable goal.

Josh
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