[YUNIKORN-1798] Move prefilter plugins out of node predicates to improve performance

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Component/s: core - scheduler, shim - kubernetes
• Assignee: Qi Zhu
• Reporter: Qi Zhu
• Created: 09/Jun/23 03:27
• Updated: 26/Jul/23 11:17
• Resolved: 26/Jul/23 11:17

Description

The current flow for predicate:

Tryallocate -> TryNodes -> TryNode ->  Shim Predicate(including prefilter and filter)

If we can change to:
Tryallocate -> Shim Prefilter -> TryNodes -> TryNode -> Shim filter

The current implementation put PreFilter together with Filter into Predicates, the Predicate process each pod-node pair like the following code:

 

for pod in pods:   
 for nodes in nodes:
    prePredicate(pod) # prefilters        
    predicate(pod, node) # filters

 

It's functioning well while PreFilter only needs the pod object(no node required), we don't need to put it in the inner loop. So a promotion of PreFilter to the outer loop is made in this jira for performance's sake, such as a plugin like inter-pod-afftinity is very time-consuming to prepare the pod interconnections in PreFilter. After this proposal, it will be:

 

for pod in pods:
   prePredicate(pod) # prefilters
    for nodes in nodes:
      predicate(pod, node) # filters 

 

Also for PreemptionPredicates we also can ahead the PreFilter!
cc Wilfred Spiegelenburg Craig Condit   Peter Bacsko