Wrong calculation for queue deserved in proportion plugin

[zionwu]

Is this a BUG REPORT or FEATURE REQUEST?:
/kind bug

What happened:
The kube-batch crash with following error message:

panic: Resource is not sufficient to do operation: <cpu 408833.33, memory 5346978668544.00, GPU 0.00> sub <cpu 608000.00, memory 5153960755200.00, GPU 0.00> [recovered]
	panic: Resource is not sufficient to do operation: <cpu 408833.33, memory 5346978668544.00, GPU 0.00> sub <cpu 608000.00, memory 5153960755200.00, GPU 0.00>

goroutine 246 [running]:
github.com/kubernetes-sigs/kube-batch/vendor/k8s.io/apimachinery/pkg/util/runtime.HandleCrash(0x0, 0x0, 0x0)
	/Users/klaus/Workspace/kb_ws/src/github.com/kubernetes-sigs/kube-batch/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:58 +0x108
panic(0x111cb00, 0xc00102a870)
	/usr/local/go/src/runtime/panic.go:513 +0x1b9
github.com/kubernetes-sigs/kube-batch/pkg/scheduler/api.(*Resource).Sub(0xc001003760, 0xc0010037e0, 0xc000564458)
	/Users/klaus/Workspace/kb_ws/src/github.com/kubernetes-sigs/kube-batch/pkg/scheduler/api/resource_info.go:108 +0x10e
github.com/kubernetes-sigs/kube-batch/pkg/scheduler/plugins/proportion.(*proportionPlugin).OnSessionOpen(0xc000f78360, 0xc00039a9c0)
	/Users/klaus/Workspace/kb_ws/src/github.com/kubernetes-sigs/kube-batch/pkg/scheduler/plugins/proportion/proportion.go:138 +0xefc
github.com/kubernetes-sigs/kube-batch/pkg/scheduler/framework.OpenSession(0x143e180, 0xc0002a01c0, 0xc000e4e280, 0x5, 0x8, 0x0)
	/Users/klaus/Workspace/kb_ws/src/github.com/kubernetes-sigs/kube-batch/pkg/scheduler/framework/framework.go:36 +0x275
github.com/kubernetes-sigs/kube-batch/pkg/scheduler.(*Scheduler).runOnce(0xc000395ce0)

line 138 in proportion.go(https://github.com/kubernetes-sigs/kube-batch/blob/master/pkg/scheduler/plugins/proportion/proportion.go#L138) cause this issue:

remaining.Sub(deserved)

However, deserved should always less then remaining, the root cause is the following line:

deserved.Add(attr.deserved)

deserved should not add attr.deserved . If the attr.deserved is not meet, next time it will increase then it is added to deserved again and remaining will subtract the same attr.deserverd twice.

We should change to calculate using the increment part：

queueDeserved := remaining.Clone().Multi(float64(attr.weight) / float64(totalWeight))
deserved.Add(queueDeserved)

[zionwu]

Closed as fix is merged.