On Tue, 08 Jun 2010 01:17:13 +0200, Linus Walleij said:

quoted text
> So I would really like to know from the Android people why the
> binder is in the kernel, after all. Could it *theoretically* be in
> userspace, on top of some unix domain sockets, running as a
> real-time scheduled daemon or whatever, still yielding the same
> performance? Or is there some discovered limitation with current
> interfaces, that everybody ought to know?

Not an Android person, but...

How expensive is a userspace->kernel transition on Android-class hardware?
There's certainly something to be said for short-circuiting the path
source_process -> kernel -> broker_process -> kernel -> dest_process
down to the shorter source->kernel->dest