Fixed: #1997

test(auth-scheduler): add benchmarks and priority-based scheduling improvements

- Added `BenchmarkManagerPickNextMixedPriority500` for mixed-priority performance assessment.
- Updated `pickNextMixed` to prioritize highest ready priority tiers.
- Introduced `highestReadyPriorityLocked` and `pickReadyAtPriorityLocked` for better scheduling logic.
- Added unit test to validate selection of highest priority tiers in mixed provider scenarios.

sdk/cliproxy/auth/scheduler.go

@@ -250,17 +250,41 @@ func (s *authScheduler) pickMixed(ctx context.Context, providers []string, model
 		return nil, "", shard.unavailableErrorLocked("mixed", model, predicate)
 	}
 
+	predicate := triedPredicate(tried)
+	candidateShards := make([]*modelScheduler, len(normalized))
+	bestPriority := 0
+	hasCandidate := false
+	now := time.Now()
+	for providerIndex, providerKey := range normalized {
+		providerState := s.providers[providerKey]
+		if providerState == nil {
+			continue
+		}
+		shard := providerState.ensureModelLocked(modelKey, now)
+		candidateShards[providerIndex] = shard
+		if shard == nil {
+			continue
+		}
+		priorityReady, okPriority := shard.highestReadyPriorityLocked(false, predicate)
+		if !okPriority {
+			continue
+		}
+		if !hasCandidate || priorityReady > bestPriority {
+			bestPriority = priorityReady
+			hasCandidate = true
+		}
+	}
+	if !hasCandidate {
+		return nil, "", s.mixedUnavailableErrorLocked(normalized, model, tried)
+	}
+
 	if s.strategy == schedulerStrategyFillFirst {
-		for _, providerKey := range normalized {
-			providerState := s.providers[providerKey]
-			if providerState == nil {
-				continue
-			}
-			shard := providerState.ensureModelLocked(modelKey, time.Now())
+		for providerIndex, providerKey := range normalized {
+			shard := candidateShards[providerIndex]
 			if shard == nil {
 				continue
 			}
-			picked := shard.pickReadyLocked(false, s.strategy, triedPredicate(tried))
+			picked := shard.pickReadyAtPriorityLocked(false, bestPriority, s.strategy, predicate)
 			if picked != nil {
 				return picked, providerKey, nil
 			}
@@ -276,15 +300,11 @@ func (s *authScheduler) pickMixed(ctx context.Context, providers []string, model
 	for offset := 0; offset < len(normalized); offset++ {
 		providerIndex := (start + offset) % len(normalized)
 		providerKey := normalized[providerIndex]
-		providerState := s.providers[providerKey]
-		if providerState == nil {
-			continue
-		}
-		shard := providerState.ensureModelLocked(modelKey, time.Now())
+		shard := candidateShards[providerIndex]
 		if shard == nil {
 			continue
 		}
-		picked := shard.pickReadyLocked(false, schedulerStrategyRoundRobin, triedPredicate(tried))
+		picked := shard.pickReadyAtPriorityLocked(false, bestPriority, schedulerStrategyRoundRobin, predicate)
 		if picked == nil {
 			continue
 		}
@@ -629,6 +649,19 @@ func (m *modelScheduler) pickReadyLocked(preferWebsocket bool, strategy schedule
 		return nil
 	}
 	m.promoteExpiredLocked(time.Now())
+	priorityReady, okPriority := m.highestReadyPriorityLocked(preferWebsocket, predicate)
+	if !okPriority {
+		return nil
+	}
+	return m.pickReadyAtPriorityLocked(preferWebsocket, priorityReady, strategy, predicate)
+}
+
+// highestReadyPriorityLocked returns the highest priority bucket that still has a matching ready auth.
+// The caller must ensure expired entries are already promoted when needed.
+func (m *modelScheduler) highestReadyPriorityLocked(preferWebsocket bool, predicate func(*scheduledAuth) bool) (int, bool) {
+	if m == nil {
+		return 0, false
+	}
 	for _, priority := range m.priorityOrder {
 		bucket := m.readyByPriority[priority]
 		if bucket == nil {
@@ -638,17 +671,37 @@ func (m *modelScheduler) pickReadyLocked(preferWebsocket bool, strategy schedule
 		if preferWebsocket && len(bucket.ws.flat) > 0 {
 			view = &bucket.ws
 		}
-		var picked *scheduledAuth
-		if strategy == schedulerStrategyFillFirst {
-			picked = view.pickFirst(predicate)
-		} else {
-			picked = view.pickRoundRobin(predicate)
-		}
-		if picked != nil && picked.auth != nil {
-			return picked.auth
+		if view.pickFirst(predicate) != nil {
+			return priority, true
 		}
 	}
-	return nil
+	return 0, false
+}
+
+// pickReadyAtPriorityLocked selects the next ready auth from a specific priority bucket.
+// The caller must ensure expired entries are already promoted when needed.
+func (m *modelScheduler) pickReadyAtPriorityLocked(preferWebsocket bool, priority int, strategy schedulerStrategy, predicate func(*scheduledAuth) bool) *Auth {
+	if m == nil {
+		return nil
+	}
+	bucket := m.readyByPriority[priority]
+	if bucket == nil {
+		return nil
+	}
+	view := &bucket.all
+	if preferWebsocket && len(bucket.ws.flat) > 0 {
+		view = &bucket.ws
+	}
+	var picked *scheduledAuth
+	if strategy == schedulerStrategyFillFirst {
+		picked = view.pickFirst(predicate)
+	} else {
+		picked = view.pickRoundRobin(predicate)
+	}
+	if picked == nil || picked.auth == nil {
+		return nil
+	}
+	return picked.auth
 }
 
 // unavailableErrorLocked returns the correct unavailable or cooldown error for the shard.

sdk/cliproxy/auth/scheduler_benchmark_test.go

@@ -176,6 +176,25 @@ func BenchmarkManagerPickNextMixed500(b *testing.B) {
 	}
 }
 
+func BenchmarkManagerPickNextMixedPriority500(b *testing.B) {
+	manager, providers, model := benchmarkManagerSetup(b, 500, true, true)
+	ctx := context.Background()
+	opts := cliproxyexecutor.Options{}
+	tried := map[string]struct{}{}
+	if _, _, _, errWarm := manager.pickNextMixed(ctx, providers, model, opts, tried); errWarm != nil {
+		b.Fatalf("warmup pickNextMixed error = %v", errWarm)
+	}
+
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		auth, exec, provider, errPick := manager.pickNextMixed(ctx, providers, model, opts, tried)
+		if errPick != nil || auth == nil || exec == nil || provider == "" {
+			b.Fatalf("pickNextMixed failed: auth=%v exec=%v provider=%q err=%v", auth, exec, provider, errPick)
+		}
+	}
+}
+
 func BenchmarkManagerPickNextAndMarkResult1000(b *testing.B) {
 	manager, _, model := benchmarkManagerSetup(b, 1000, false, false)
 	ctx := context.Background()

sdk/cliproxy/auth/scheduler_test.go

@@ -237,6 +237,41 @@ func TestSchedulerPick_MixedProvidersUsesProviderRotationOverReadyCandidates(t *
 	}
 }
 
+func TestSchedulerPick_MixedProvidersPrefersHighestPriorityTier(t *testing.T) {
+	t.Parallel()
+
+	model := "gpt-default"
+	registerSchedulerModels(t, "provider-low", model, "low")
+	registerSchedulerModels(t, "provider-high-a", model, "high-a")
+	registerSchedulerModels(t, "provider-high-b", model, "high-b")
+
+	scheduler := newSchedulerForTest(
+		&RoundRobinSelector{},
+		&Auth{ID: "low", Provider: "provider-low", Attributes: map[string]string{"priority": "4"}},
+		&Auth{ID: "high-a", Provider: "provider-high-a", Attributes: map[string]string{"priority": "7"}},
+		&Auth{ID: "high-b", Provider: "provider-high-b", Attributes: map[string]string{"priority": "7"}},
+	)
+
+	providers := []string{"provider-low", "provider-high-a", "provider-high-b"}
+	wantProviders := []string{"provider-high-a", "provider-high-b", "provider-high-a", "provider-high-b"}
+	wantIDs := []string{"high-a", "high-b", "high-a", "high-b"}
+	for index := range wantProviders {
+		got, provider, errPick := scheduler.pickMixed(context.Background(), providers, model, cliproxyexecutor.Options{}, nil)
+		if errPick != nil {
+			t.Fatalf("pickMixed() #%d error = %v", index, errPick)
+		}
+		if got == nil {
+			t.Fatalf("pickMixed() #%d auth = nil", index)
+		}
+		if provider != wantProviders[index] {
+			t.Fatalf("pickMixed() #%d provider = %q, want %q", index, provider, wantProviders[index])
+		}
+		if got.ID != wantIDs[index] {
+			t.Fatalf("pickMixed() #%d auth.ID = %q, want %q", index, got.ID, wantIDs[index])
+		}
+	}
+}
+
 func TestManager_PickNextMixed_UsesProviderRotationBeforeCredentialRotation(t *testing.T) {
 	t.Parallel()