fix: refcount StatsCache keys, keep registrations across config change, and tidy GPU/usage render paths

src/lib/runtime.ts

@@ -12,7 +12,6 @@ class Runtime {
   private feed?: EventFeed;
   private poller?: MetricsPoller;
   private statsCache?: StatsCache;
-  private statsUnsub?: () => void;
   private listeners = new Set<() => void>();
 
   ensureConnections(cfg: LlamaSwapConfig): void {
@@ -22,9 +21,7 @@ class Runtime {
       this.poller?.stop();
       this.feed = undefined;
       this.poller = undefined;
-      this.statsUnsub?.();
-      this.statsCache = undefined;
-      this.statsUnsub = undefined;
+      this.statsCache?.setConfig(cfg);
       this.cfg = cfg;
     }
     if (!this.feed) {
@@ -46,7 +43,7 @@ class Runtime {
     }
     if (!this.statsCache) {
       this.statsCache = new StatsCache(cfg);
-      this.statsUnsub = this.statsCache.onChange(() => this.emit());
+      this.statsCache.onChange(() => this.emit());
     }
   }
 

src/lib/stats-cache.ts

@@ -7,7 +7,8 @@ const ACTIVITY_THROTTLE_MS = 2000;
 export type FetchFn = (cfg: LlamaSwapConfig, modelId: string) => Promise<UsageStats | null>;
 
 export class StatsCache {
-  private keys = new Set<string>();
+  private refs = new Map<string, number>();
+  private refreshing = false;
   private values = new Map<string, UsageStats | undefined>();
   private listeners = new Set<() => void>();
   private timer?: ReturnType<typeof setInterval>;
@@ -27,8 +28,7 @@ export class StatsCache {
   }
 
   register(key: string): void {
-    if (this.keys.has(key)) return;
-    this.keys.add(key);
+    this.refs.set(key, (this.refs.get(key) ?? 0) + 1);
     if (!this.timer) {
       void this.refresh();
       this.timer = setInterval(() => void this.refresh(), this.pollMs);
@@ -36,11 +36,18 @@ export class StatsCache {
   }
 
   unregister(key: string): void {
-    this.keys.delete(key);
-    this.values.delete(key);
-    if (this.keys.size === 0 && this.timer) {
-      clearInterval(this.timer);
+    const count = (this.refs.get(key) ?? 0) - 1;
+    if (count <= 0) {
+      this.refs.delete(key);
+      this.values.delete(key);
+    } else {
+      this.refs.set(key, count);
+    }
+    if (this.refs.size === 0) {
+      if (this.timer) clearInterval(this.timer);
       this.timer = undefined;
+      if (this.throttleTimer) clearTimeout(this.throttleTimer);
+      this.throttleTimer = undefined;
     }
   }
 
@@ -59,15 +66,21 @@ export class StatsCache {
   }
 
   async refresh(): Promise<void> {
-    this.lastRefresh = Date.now();
-    for (const key of this.keys) {
-      try {
-        const stats = await this.fetchFn(this.cfg, key);
-        if (stats) this.values.set(key, stats);
-      } catch {
+    if (this.refreshing) return;
+    this.refreshing = true;
+    try {
+      for (const key of this.refs.keys()) {
+        try {
+          const stats = await this.fetchFn(this.cfg, key);
+          if (stats) this.values.set(key, stats);
+        } catch {
+        }
       }
+    } finally {
+      this.refreshing = false;
+      this.lastRefresh = Date.now();
+      this.emit();
     }
-    this.emit();
   }
 
   onChange(listener: () => void): () => void {