This adds new benchmark tests that measure scheduler latency of pods
that use affinity rules. Specifically, this tests affinity rules with
topologyKey="kubernetes.io/hostname".
Under the default behavior of Go benchmark tests, all our scheduler_perf
benchmark tests run with b.N=1, which is lower than we would like. This
adds a lower bound to b.N so that the results are more meaningful.
The alternative to this change is to always run these tests with the
-benchtime flag set to a duration which will force b.N to increase. That
would cause any test setup to be executed repeatedly as b.N ramps up,
and -timout would probably also need to be set higher.
Where possible, switch the scheduler to use generated listers and
informers. There are still some places where it probably makes more
sense to use one-off reflectors/informers (listing/watching just a
single node, listing/watching scheduled & unscheduled pods using a field
selector).
Jonathan Basseri