[Cake] profiling using perf

[Jonathan Morton]

> On 11 Mar, 2019, at 4:49 pm, Adrian Popescu <adriannnpopescu at gmail.com> wrote:
> 
> This doesn't mean cake is poorly optimized or poorly
> implemented. It's not a good fit for small embedded systems with small
> CPU caches.

More importantly, how much CPU time is spent elsewhere than in sch_cake.c?  I suspect there's a lot of overhead that we have only indirect control over.

 - Jonathan Morton