[Qbs] Qbs (way) faster than cmake (or benchmark issue)

[Oswald Buddenhagen]

On Mon, Jul 22, 2019 at 11:00:07AM +1200, Christian Gagneraud wrote:
> At the 20 jobs mark, cmake start to stagnate, whereas qbs still make
> use of parallelism, at the 30 jobs mark, cmake completely stopped
> reducing overall build time, whereas qbs start to stagnate. At the 40
> jobs mark, both systems are stale.
> 
that means that qbs creates a build graph with fewer bottlenecks. cmake
certainly could do that with relatively little effort as well, at the
likely cost of slightly increased null rebuild times (due to the graph
being bigger).

some suggestions for making a diagram where the interesting stuff isn't
crammed into a narrow strip at the bottom:
- a logarithmic job count axis
- build speed per job vs. job count
- cpu utilization per core vs. job count
- <your idea here>