Increase concurrency of reconcile scenario

The scenario wasn't able to generate the desired load as the reconciler's throuput was limited by the number of concurrent workers
(all workers were active all the time and work items were piling up in the queue).

webhosting-operator/pkg/experiment/generator/reconciler.go

@@ -37,30 +37,36 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/reconcile"
 )
 
-const reconcileWorkers = 10
+const defaultReconcileWorkers = 10
 
 // Every runs the given Func with the specified frequency.
 type Every struct {
 	client.Client
 
-	Name string
-	Do   func(ctx context.Context, c client.Client) error
-	Rate rate.Limit
-	Stop time.Time
+	Name    string
+	Do      func(ctx context.Context, c client.Client) error
+	Rate    rate.Limit
+	Stop    time.Time
+	Workers int
 }
 
 func (r *Every) AddToManager(mgr manager.Manager) error {
 	if r.Client == nil {
 		r.Client = mgr.GetClient()
 	}
 
+	workers := defaultReconcileWorkers
+	if r.Workers > 0 {
+		workers = r.Workers
+	}
+
 	return builder.ControllerManagedBy(mgr).
 		Named(r.Name).
 		WithOptions(controller.Options{
-			MaxConcurrentReconciles: reconcileWorkers,
+			MaxConcurrentReconciles: workers,
 			RateLimiter:             &workqueue.BucketRateLimiter{Limiter: rate.NewLimiter(r.Rate, int(r.Rate))},
 		}).
-		WatchesRawSource(EmitN(reconcileWorkers), &handler.EnqueueRequestForObject{}).
+		WatchesRawSource(EmitN(workers), &handler.EnqueueRequestForObject{}).
 		Complete(StopOnContextCanceled(r))
 }
 
@@ -77,10 +83,11 @@ func (r *Every) Reconcile(ctx context.Context, _ reconcile.Request) (reconcile.R
 type ForEach[T client.Object] struct {
 	client.Client
 
-	Name      string
-	Do        func(ctx context.Context, c client.Client, obj T) error
-	Every     time.Duration
-	Stop      time.Time
+	Name    string
+	Do      func(ctx context.Context, c client.Client, obj T) error
+	Every   time.Duration
+	Stop    time.Time
+	Workers int
 
 	gvk schema.GroupVersionKind
 	obj T
@@ -100,10 +107,15 @@ func (r *ForEach[T]) AddToManager(mgr manager.Manager) error {
 		return err
 	}
 
+	workers := defaultReconcileWorkers
+	if r.Workers > 0 {
+		workers = r.Workers
+	}
+
 	return builder.ControllerManagedBy(mgr).
 		Named(r.Name).
 		WithOptions(controller.Options{
-			MaxConcurrentReconciles: reconcileWorkers,
+			MaxConcurrentReconciles: workers,
 			RateLimiter:             unlimitedRateLimiter(),
 		}).
 		Watches(

webhosting-operator/pkg/experiment/scenario/reconcile/reconcile.go

@@ -74,13 +74,14 @@ func (s *scenario) Prepare(ctx context.Context) error {
 }
 
 func (s *scenario) Run(ctx context.Context) error {
-	// trigger individual reconciliations for website every 10s
+	// trigger individual reconciliations for websites every 10s
 	if err := (&generator.ForEach[*webhostingv1alpha1.Website]{
 		Name: "website-reconcile-trigger",
 		Do: func(ctx context.Context, c client.Client, obj *webhostingv1alpha1.Website) error {
 			return client.IgnoreNotFound(generator.ReconcileWebsite(ctx, c, obj))
 		},
-		Every: 10 * time.Second,
+		Every:   10 * time.Second,
+		Workers: 50,
 	}).AddToManager(s.Manager); err != nil {
 		return fmt.Errorf("error adding website-reconcile-trigger: %w", err)
 	}