From 7c2ed78d85003267f0b0513af16e45b53395255d Mon Sep 17 00:00:00 2001
From: Arik Hadas <ahadas@redhat.com>
Date: Sun, 9 Jun 2024 17:10:46 +0300
Subject: [PATCH] vsphere: virt-v2v transfers disks sequentially

when scheduling migrations to accommodate the controller_max_vm_inflight
setting for vSphere, we didn't take into account that disks are
transferred sequentially by virt-v2v (as opposed to CDI that transfers
them in parallel by different pods). This lead to performance
degregeration since could have triggered more migrations, in case of
migrations of multi-disk VMs, simultaneously without exceeding the value
of controller_max_vm_inflight. This is fixed by setting the cost of each
VM for which the disks are transferred by virt-v2v to 1.

Signed-off-by: Arik Hadas <ahadas@redhat.com>
---
 .../plan/scheduler/vsphere/scheduler.go          | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/pkg/controller/plan/scheduler/vsphere/scheduler.go b/pkg/controller/plan/scheduler/vsphere/scheduler.go
index 100130c90..2e7159450 100644
--- a/pkg/controller/plan/scheduler/vsphere/scheduler.go
+++ b/pkg/controller/plan/scheduler/vsphere/scheduler.go
@@ -107,7 +107,7 @@ func (r *Scheduler) buildInFlight() (err error) {
 			return
 		}
 		if vmStatus.Running() {
-			r.inFlight[vm.Host] += len(vm.Disks)
+			r.inFlight[vm.Host] += r.cost(vm)
 		}
 	}
 
@@ -148,7 +148,7 @@ func (r *Scheduler) buildInFlight() (err error) {
 				}
 				return err
 			}
-			r.inFlight[vm.Host] += len(vm.Disks)
+			r.inFlight[vm.Host] += r.cost(vm)
 		}
 	}
 
@@ -169,7 +169,7 @@ func (r *Scheduler) buildPending() (err error) {
 		if !vmStatus.MarkedStarted() && !vmStatus.MarkedCompleted() {
 			pending := &pendingVM{
 				status: vmStatus,
-				cost:   len(vm.Disks),
+				cost:   r.cost(vm),
 			}
 			r.pending[vm.Host] = append(r.pending[vm.Host], pending)
 		}
@@ -177,6 +177,16 @@ func (r *Scheduler) buildPending() (err error) {
 	return
 }
 
+func (r *Scheduler) cost(vm *model.VM) int {
+	if el9, _ := r.Plan.VSphereUsesEl9VirtV2v(); el9 {
+		/// virt-v2v transfers one disk at a time
+		return 1
+	} else {
+		// CDI transfers the disks in parallel by different pods
+		return len(vm.Disks)
+	}
+}
+
 // Return a map of all the VMs that could be scheduled
 // based on the available host capacities.
 func (r *Scheduler) schedulable() (schedulable map[string][]*pendingVM) {