1 files changed, 328 insertions, 0 deletions
diff --git a/js/src/devtools/gc-ubench/harness.js b/js/src/devtools/gc-ubench/harness.js
new file mode 100644
index 0000000000..db7fa06d63
--- /dev/null
+++ b/js/src/devtools/gc-ubench/harness.js
@@ -0,0 +1,328 @@
+/* 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/. */
+
+// Global defaults
+
+// Allocate this much "garbage" per frame. This might correspond exactly to a
+// number of objects/values, or it might be some set of objects, depending on
+// the mutator in question.
+var gDefaultGarbagePerFrame = "8K";
+
+// In order to avoid a performance cliff between when the per-frame garbage
+// fits in the nursery and when it doesn't, most mutators will collect multiple
+// "piles" of garbage and round-robin through them, so that the per-frame
+// garbage stays alive for some number of frames. There will still be some
+// internal temporary allocations that don't end up in the piles; presumably,
+// the nursery will take care of those.
+//
+// If the per-frame garbage is K and the number of piles is P, then some of the
+// garbage will start getting tenured as long as P*K > size(nursery).
+var gDefaultGarbagePiles = "8";
+
+var gDefaultTestDuration = 8.0;
+
+// The Host interface that provides functionality needed by the test harnesses
+// (web + various shells). Subclasses should override with the appropriate
+// functionality. The methods that throw an error must be implemented. The ones
+// that return undefined are optional.
+//
+// Note that currently the web UI doesn't really use the scheduling pieces of
+// this.
+var Host = class {
+  constructor() {}
+  start_turn() {
+    throw new Error("unimplemented");
+  }
+  end_turn() {
+    throw new Error("unimplemented");
+  }
+  suspend(duration) {
+    throw new Error("unimplemented");
+  } // Shell driver only
+  now() {
+    return performance.now();
+  }
+
+  minorGCCount() {
+    return undefined;
+  }
+  majorGCCount() {
+    return undefined;
+  }
+  GCSliceCount() {
+    return undefined;
+  }
+
+  features = {
+    haveMemorySizes: false,
+    haveGCCounts: false,
+  };
+};
+
+function percent(x) {
+  return `${(x*100).toFixed(2)}%`;
+}
+
+function parse_units(v) {
+  if (!v.length) {
+    return NaN;
+  }
+  var lastChar = v[v.length - 1].toLowerCase();
+  if (!isNaN(parseFloat(lastChar))) {
+    return parseFloat(v);
+  }
+  var units = parseFloat(v.substr(0, v.length - 1));
+  if (lastChar == "k") {
+    return units * 1e3;
+  }
+  if (lastChar == "m") {
+    return units * 1e6;
+  }
+  if (lastChar == "g") {
+    return units * 1e9;
+  }
+  return NaN;
+}
+
+var AllocationLoad = class {
+  constructor(info, name) {
+    this.load = info;
+    this.load.name = this.load.name ?? name;
+
+    this._garbagePerFrame =
+      info.garbagePerFrame ||
+      parse_units(info.defaultGarbagePerFrame || gDefaultGarbagePerFrame);
+    this._garbagePiles =
+      info.garbagePiles ||
+      parse_units(info.defaultGarbagePiles || gDefaultGarbagePiles);
+  }
+
+  get name() {
+    return this.load.name;
+  }
+  get description() {
+    return this.load.description;
+  }
+  get garbagePerFrame() {
+    return this._garbagePerFrame;
+  }
+  set garbagePerFrame(amount) {
+    this._garbagePerFrame = amount;
+  }
+  get garbagePiles() {
+    return this._garbagePiles;
+  }
+  set garbagePiles(amount) {
+    this._garbagePiles = amount;
+  }
+
+  start() {
+    this.load.load(this._garbagePiles);
+  }
+
+  stop() {
+    this.load.unload();
+  }
+
+  reload() {
+    this.stop();
+    this.start();
+  }
+
+  tick() {
+    this.load.makeGarbage(this._garbagePerFrame);
+  }
+
+  is_dummy_load() {
+    return this.load.name == "noAllocation";
+  }
+};
+
+var AllocationLoadManager = class {
+  constructor(tests) {
+    this._loads = new Map();
+    for (const [name, info] of tests.entries()) {
+      this._loads.set(name, new AllocationLoad(info, name));
+    }
+    this._active = undefined;
+    this._paused = false;
+
+    // Public API
+    this.sequencer = null;
+    this.testDurationMS = gDefaultTestDuration * 1000;
+  }
+
+  getByName(name) {
+    const mutator = this._loads.get(name);
+    if (!mutator) {
+      throw new Error(`invalid mutator '${name}'`);
+    }
+    return mutator;
+  }
+
+  activeLoad() {
+    return this._active;
+  }
+
+  setActiveLoad(mutator) {
+    if (this._active) {
+      this._active.stop();
+    }
+    this._active = mutator;
+    this._active.start();
+  }
+
+  deactivateLoad() {
+    this._active.stop();
+    this._active = undefined;
+  }
+
+  get paused() {
+    return this._paused;
+  }
+  set paused(pause) {
+    this._paused = pause;
+  }
+
+  load_running() {
+    return this._active;
+  }
+
+  change_garbagePiles(amount) {
+    if (this._active) {
+      this._active.garbagePiles = amount;
+      this._active.reload();
+    }
+  }
+
+  change_garbagePerFrame(amount) {
+    if (this._active) {
+      this._active.garbagePerFrame = amount;
+    }
+  }
+
+  tick(now = gHost.now()) {
+    this.lastActive = this._active;
+    let completed = false;
+
+    if (this.sequencer) {
+      if (this.sequencer.tick(now)) {
+        completed = true;
+        if (this.sequencer.current) {
+          this.setActiveLoad(this.sequencer.current);
+        } else {
+          this.deactivateLoad();
+        }
+        if (this.sequencer.done()) {
+          this.sequencer = null;
+        }
+      }
+    }
+
+    if (this._active && !this._paused) {
+      this._active.tick();
+    }
+
+    return completed;
+  }
+
+  startSequencer(sequencer, now = gHost.now()) {
+    this.sequencer = sequencer;
+    this.sequencer.start(now);
+    this.setActiveLoad(this.sequencer.current);
+  }
+
+  stopped() {
+    return !this.sequencer || this.sequencer.done();
+  }
+
+  currentLoadRemaining(now = gHost.now()) {
+    if (this.stopped()) {
+      return 0;
+    }
+
+    // TODO: The web UI displays a countdown to the end of the current mutator.
+    // This won't work for potential future things like "run until 3 major GCs
+    // have been seen", so the API will need to be modified to provide
+    // information in that case.
+    return this.testDurationMS - this.sequencer.currentLoadElapsed(now);
+  }
+};
+
+// Current test state.
+var gLoadMgr = undefined;
+
+function format_with_units(n, label, shortlabel, kbase) {
+  if (n < kbase * 4) {
+    return `${n} ${label}`;
+  } else if (n < kbase ** 2 * 4) {
+    return `${(n / kbase).toFixed(2)}K${shortlabel}`;
+  } else if (n < kbase ** 3 * 4) {
+    return `${(n / kbase ** 2).toFixed(2)}M${shortlabel}`;
+  }
+  return `${(n / kbase ** 3).toFixed(2)}G${shortlabel}`;
+}
+
+function format_bytes(bytes) {
+  return format_with_units(bytes, "bytes", "B", 1024);
+}
+
+function format_num(n) {
+  return format_with_units(n, "", "", 1000);
+}
+
+function update_histogram(histogram, delay) {
+  // Round to a whole number of 10us intervals to provide enough resolution to
+  // capture a 16ms target with adequate accuracy.
+  delay = Math.round(delay * 100) / 100;
+  var current = histogram.has(delay) ? histogram.get(delay) : 0;
+  histogram.set(delay, ++current);
+}
+
+// Compute a score based on the total ms we missed frames by per second.
+function compute_test_score(histogram) {
+  var score = 0;
+  for (let [delay, count] of histogram) {
+    score += Math.abs((delay - 1000 / 60) * count);
+  }
+  score = score / (gLoadMgr.testDurationMS / 1000);
+  return Math.round(score * 1000) / 1000;
+}
+
+// Build a spark-lines histogram for the test results to show with the aggregate score.
+function compute_spark_histogram_percents(histogram) {
+  var ranges = [
+    [-99999999, 16.6],
+    [16.6, 16.8],
+    [16.8, 25],
+    [25, 33.4],
+    [33.4, 60],
+    [60, 100],
+    [100, 300],
+    [300, 99999999],
+  ];
+  var rescaled = new Map();
+  for (let [delay] of histogram) {
+    for (var i = 0; i < ranges.length; ++i) {
+      var low = ranges[i][0];
+      var high = ranges[i][1];
+      if (low <= delay && delay < high) {
+        update_histogram(rescaled, i);
+        break;
+      }
+    }
+  }
+  var total = 0;
+  for (const [, count] of rescaled) {
+    total += count;
+  }
+
+  var spark = [];
+  for (let i = 0; i < ranges.length; ++i) {
+    const amt = rescaled.has(i) ? rescaled.get(i) : 0;
+    spark.push(amt / total);
+  }
+
+  return spark;
+}