We have some labels assigned to various nodes and we run certain things in a relatively complex build process involving a shared Jenkins library. There it happens quite often that the pipeline has multiple nested 'node' steps running with exactly the same labels.

node('mylabel') {
   for (int i = 0; i < 1000; i++) {
      node('mylabel') {
         sleep(10)
      }
   }
}

Jenkins ends up switching the node all the time, causing quite a bit of lock contention on the Queue processing. In this case the node step should have some kind of a mechanism to know that it is already on a suitable node and no node switch is required.

Imagine this scenario with a 100 jobs with around 20 parallel stages each, the builds grind to a halt. This should be more scalable.