1 files changed, 64 insertions, 0 deletions
diff --git a/js/src/devtools/gc-ubench/scheduler.js b/js/src/devtools/gc-ubench/scheduler.js
new file mode 100644
index 0000000000..8f4a483b33
--- /dev/null
+++ b/js/src/devtools/gc-ubench/scheduler.js
@@ -0,0 +1,64 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Frame schedulers: executing a frame's worth of mutation, and possibly
+// waiting for a later frame. (These schedulers will halt the main thread,
+// allowing background threads to continue working.)
+
+var Scheduler = class {
+  constructor(perfMonitor) {
+    this._perfMonitor = perfMonitor;
+  }
+
+  start(loadMgr, timestamp) {
+    return loadMgr.start(timestamp);
+  }
+  tick(loadMgr, timestamp) {}
+  wait_for_next_frame(t0, tick_start, tick_end) {}
+};
+
+// "Sync to vsync" scheduler: after the mutator is done for a frame, wait until
+// the beginning of the next 60fps frame.
+var VsyncScheduler = class extends Scheduler {
+  tick(loadMgr, timestamp) {
+    this._perfMonitor.before_mutator(timestamp);
+    gHost.start_turn();
+    const completed = loadMgr.tick(timestamp);
+    gHost.end_turn();
+    this._perfMonitor.after_mutator(timestamp);
+    return completed;
+  }
+
+  wait_for_next_frame(t0, tick_start, tick_end) {
+    // Compute how long until the next 60fps vsync event, and wait that long.
+    const elapsed = (tick_end - t0) / 1000;
+    const period = 1 / FPS;
+    const used = elapsed % period;
+    const delay = period - used;
+    gHost.suspend(delay);
+    this._perfMonitor.after_suspend(delay);
+  }
+};
+
+// Try to maintain 60fps, but if we overrun a frame, do more processing
+// immediately to make the next frame come up as soon as possible.
+var OptimizeForFrameRate = class extends Scheduler {
+  tick(loadMgr, timestamp) {
+    this._perfMonitor.before_mutator(timestamp);
+    gHost.start_turn();
+    const completed = loadMgr.tick(timestamp);
+    gHost.end_turn();
+    this._perfMonitor.after_mutator(timestamp);
+    return completed;
+  }
+
+  wait_for_next_frame(t0, tick_start, tick_end) {
+    const next_frame_ms = round_up(tick_start, 1000 / FPS);
+    if (tick_end < next_frame_ms) {
+      const delay = (next_frame_ms - tick_end) / 1000;
+      gHost.suspend(delay);
+      this._perfMonitor.after_suspend(delay);
+    }
+  }
+};