Automatic merge from submit-queue
Optimize label selector
The number of values for a given label is generally pretty small (in huge majority of cases it is exactly one value).
Currently computing selectors is up to 50% of CPU usage in both apiserver and scheduler.
Changing the structure in which those values are stored from map to slice improves the performance of typical usecase for computing selectors.
Early results:
- scheduler throughput it ~15% higher
- apiserver cpu-usage is also lower (seems to be also ~10-15%)