Implement a better dashboard for running benchmarks

benchmark/lib/dashboard_model.dart

Index: benchmark/lib/dashboard_model.dart
diff --git a/benchmark/lib/dashboard_model.dart b/benchmark/lib/dashboard_model.dart
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+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library protoc.benchmark.dashboard_model;
+
+import 'generated/benchmark.pb.dart' as pb;
+
+/// Contains the viewable state of the dashboard. (Immutable.)
+class DashboardModel {
+  final Map<String, pb.Report> savedReports;
+  // The name of the saved report to display.
+  final String baselineName;
+
+  final pb.Report latest;
+
+  DashboardModel(this.savedReports, this.baselineName, this.latest);
+
+  DashboardModel withBaseline(String name) =>
+      new DashboardModel(savedReports, name, latest);
+
+  DashboardModel withReport(pb.Report right) =>
+      new DashboardModel(savedReports, baselineName, right);
+
+  /// Returns true if the Run button should be enabled.
+  bool get canRun => !latest.hasStatus() || latest.status != pb.Status.RUNNING;
+
+  /// Returns the samples to use for comparison.
+  BaselineSamples getBaselineSamples() {
+    var r = savedReports[baselineName];
+    if (r == null) return new BaselineSamples([]);
+    return new BaselineSamples(r.responses);
+  }
+}
+
+class BaselineSamples {
+  final samples = <String, pb.Sample>{};
+  BaselineSamples(List<pb.Response> responses) {
+    for (var response in responses) {
+      samples[_key(response.request)] = medianSample(response);
+    }
+  }
+
+  pb.Sample getSample(pb.Request request) => samples[_key(request)];
+
+  String _key(pb.Request request) =>
+    request.id.name + "-" + request.params.toString();
+}
+
+/// Returns the sample with the median ints reads per second.
+pb.Sample medianSample(pb.Response response) {
+  if (response.samples.isEmpty) return null;
+  var samples = []..addAll(response.samples);
+  samples.sort((a, b) {
+    return intReadsPerSecond(a).compareTo(intReadsPerSecond(b));
+  });
+  int index = samples.length ~/ 2;
+  print("length: ${samples.length} index: $index");
+  return samples[index];
+}
+
+/// Returns the sample with the best int reads per second.
+pb.Sample maxSample(pb.Response response) {
+  pb.Sample best;
+  for (var s in response.samples) {
+    if (best == null) best = s;
+    if (intReadsPerSecond(best) < intReadsPerSecond(s)) {
+      best = s;
+    }
+  }
+  return best;
+}
+
+double intReadsPerSecond(pb.Sample s) =>
+  s.counts.int32Reads * 1000000 / s.duration;