fix(engine): scale Chrome memory budget and frame cache to system RAM

packages/engine/src/config.ts

@@ -6,6 +6,8 @@
  * fallbacks for backward compatibility during migration.
  */
 
+import { totalmem } from "os";
+
 /**
  * Full engine configuration. All fields are wired through the config
  * object; env vars serve as backward-compatible fallbacks resolved
@@ -208,6 +210,24 @@ export const DEFAULT_CONFIG: EngineConfig = {
   debug: false,
 };
 
+function getSystemTotalMb(): number {
+  return Math.floor(totalmem() / (1024 * 1024));
+}
+
+function memoryAdaptiveCacheLimit(): number {
+  const total = getSystemTotalMb();
+  if (total < 4096) return 32;
+  if (total < 8192) return 64;
+  return DEFAULT_CONFIG.frameDataUriCacheLimit;
+}
+
+function memoryAdaptiveCacheBytesMb(): number {
+  const total = getSystemTotalMb();
+  if (total < 4096) return 128;
+  if (total < 8192) return 256;
+  return DEFAULT_CONFIG.frameDataUriCacheBytesLimitMb;
+}
+
 /**
  * Resolve configuration by merging: defaults ← env vars ← explicit overrides.
  * Env vars provide backward compatibility during migration; explicit config
@@ -298,14 +318,11 @@ export function resolveConfig(overrides?: Partial<EngineConfig>): EngineConfig {
     audioGain: envNum("PRODUCER_AUDIO_GAIN", DEFAULT_CONFIG.audioGain),
     frameDataUriCacheLimit: Math.max(
       32,
-      envNum("PRODUCER_FRAME_DATA_URI_CACHE_LIMIT", DEFAULT_CONFIG.frameDataUriCacheLimit),
+      envNum("PRODUCER_FRAME_DATA_URI_CACHE_LIMIT", memoryAdaptiveCacheLimit()),
     ),
     frameDataUriCacheBytesLimitMb: Math.max(
       64,
-      envNum(
-        "PRODUCER_FRAME_DATA_URI_CACHE_BYTES_MB",
-        DEFAULT_CONFIG.frameDataUriCacheBytesLimitMb,
-      ),
+      envNum("PRODUCER_FRAME_DATA_URI_CACHE_BYTES_MB", memoryAdaptiveCacheBytesMb()),
     ),
 
     playerReadyTimeout: envNum(

packages/engine/src/services/browserManager.ts

@@ -6,9 +6,10 @@
  */
 
 import type { Browser, PuppeteerNode } from "puppeteer-core";
+import { execSync } from "child_process";
 import { existsSync, readdirSync } from "fs";
 import { join } from "path";
-import { homedir } from "os";
+import { homedir, totalmem } from "os";
 import { DEFAULT_CONFIG, type EngineConfig } from "../config.js";
 
 let _puppeteer: PuppeteerNode | undefined;
@@ -476,6 +477,49 @@ export function _setPuppeteerForTests(mock: PuppeteerNode | undefined): void {
   _puppeteer = mock;
 }
 
+function getTotalMemMb(): number {
+  return Math.floor(totalmem() / (1024 * 1024));
+}
+
+let _cachedVramMb: number | null = null;
+
+function probeNvidiaVramMb(): number | null {
+  if (_cachedVramMb !== null) return _cachedVramMb;
+  try {
+    // Synchronous, runs once per process (cached). ~50ms on typical systems.
+    const out = execSync("nvidia-smi --query-gpu=memory.total --format=csv,noheader,nounits", {
+      timeout: 3000,
+      encoding: "utf-8",
+      stdio: ["pipe", "pipe", "pipe"],
+    }).trim();
+    const mb = parseInt(out.split("\n")[0] ?? "", 10);
+    if (Number.isFinite(mb) && mb > 0) {
+      _cachedVramMb = mb;
+      return mb;
+    }
+  } catch {
+    // nvidia-smi not available or no NVIDIA GPU
+  }
+  return null;
+}
+
+function getGpuMemBudgetMb(): number {
+  const vram = probeNvidiaVramMb();
+  if (vram) return Math.min(vram, 16384);
+
+  const total = getTotalMemMb();
+  if (total < 4096) return 512;
+  if (total < 8192) return 1024;
+  return Math.min(Math.floor(total / 2), 16384);
+}
+
+function getLowMemoryFlags(): string[] {
+  const total = getTotalMemMb();
+  if (total >= 8192) return [];
+  const heapMb = total < 4096 ? 256 : 512;
+  return [`--js-flags=--max-old-space-size=${heapMb}`];
+}
+
 export interface BuildChromeArgsOptions {
   width: number;
   height: number;
@@ -530,9 +574,10 @@ export function buildChromeArgs(
     "--disable-print-preview",
     "--no-pings",
     "--no-zygote",
-    // Memory
-    "--force-gpu-mem-available-mb=4096",
+    // Memory — scale GPU budget to available system RAM
+    `--force-gpu-mem-available-mb=${getGpuMemBudgetMb()}`,
     "--disk-cache-size=268435456",
+    ...getLowMemoryFlags(),
     // Disable features that add overhead
     "--disable-features=AudioServiceOutOfProcess,IsolateOrigins,site-per-process,Translate,BackForwardCache,IntensiveWakeUpThrottling",
   ];