On Tue, Jan 14, 2014 at 04:39:54PM +0000, Morten Rasmussen wrote:

Responsiveness is still very important. It is quite hard to control. CFS
doesn't consider latency. The only way to get the best responsiveness is
to go for best performance which comes at a high cost in energy.

The big problem is that the normal unix task model doesn't cover his at
all -- nice isn't much of a knob.

There's ways in which you can adapt CFS to include such a measure
(search for the EEVDF patches), but I was kinda hoping that tasks that
really desire responsiveness could be made to use SCHED_DEADLINE or
such.