diff --git a/packages/benchpress/src/metric/perflog_metric.ts b/packages/benchpress/src/metric/perflog_metric.ts
index f31fc6186d..033c1b6da5 100644
--- a/packages/benchpress/src/metric/perflog_metric.ts
+++ b/packages/benchpress/src/metric/perflog_metric.ts
@@ -19,18 +19,21 @@ import {PerfLogEvent, PerfLogFeatures, WebDriverExtension} from '../web_driver_e
 @Injectable()
 export class PerflogMetric extends Metric {
   static SET_TIMEOUT = new InjectionToken('PerflogMetric.setTimeout');
+  static IGNORE_NAVIGATION = new InjectionToken('PerflogMetric.ignoreNavigation');
   static PROVIDERS = [
     {
       provide: PerflogMetric,
       deps: [
         WebDriverExtension, PerflogMetric.SET_TIMEOUT, Options.MICRO_METRICS, Options.FORCE_GC,
-        Options.CAPTURE_FRAMES, Options.RECEIVED_DATA, Options.REQUEST_COUNT
+        Options.CAPTURE_FRAMES, Options.RECEIVED_DATA, Options.REQUEST_COUNT,
+        PerflogMetric.IGNORE_NAVIGATION
       ]
     },
     {
       provide: PerflogMetric.SET_TIMEOUT,
       useValue: (fn: Function, millis: number) => <any>setTimeout(fn, millis)
-    }
+    },
+    {provide: PerflogMetric.IGNORE_NAVIGATION, useValue: false}
   ];
 
   private _remainingEvents: PerfLogEvent[];
@@ -41,6 +44,8 @@ export class PerflogMetric extends Metric {
    * @param driverExtension
    * @param setTimeout
    * @param microMetrics Name and description of metrics provided via console.time / console.timeEnd
+   * @param ignoreNavigation If true, don't measure from navigationStart events. These events are
+   *   usually triggered by a page load, but can also be triggered when adding iframes to the DOM.
    **/
   constructor(
       private _driverExtension: WebDriverExtension,
@@ -49,7 +54,8 @@ export class PerflogMetric extends Metric {
       @Inject(Options.FORCE_GC) private _forceGc: boolean,
       @Inject(Options.CAPTURE_FRAMES) private _captureFrames: boolean,
       @Inject(Options.RECEIVED_DATA) private _receivedData: boolean,
-      @Inject(Options.REQUEST_COUNT) private _requestCount: boolean) {
+      @Inject(Options.REQUEST_COUNT) private _requestCount: boolean,
+      @Inject(PerflogMetric.IGNORE_NAVIGATION) private _ignoreNavigation: boolean) {
     super();
 
     this._remainingEvents = [];
@@ -231,7 +237,7 @@ export class PerflogMetric extends Metric {
       const name = event['name'];
       if (ph === 'B' && name === markName) {
         markStartEvent = event;
-      } else if (ph === 'I' && name === 'navigationStart') {
+      } else if (ph === 'I' && name === 'navigationStart' && !this._ignoreNavigation) {
         // if a benchmark measures reload of a page, use the last
         // navigationStart as begin event
         markStartEvent = event;
diff --git a/packages/benchpress/test/metric/perflog_metric_spec.ts b/packages/benchpress/test/metric/perflog_metric_spec.ts
index 68822092f9..a8ad908d50 100644
--- a/packages/benchpress/test/metric/perflog_metric_spec.ts
+++ b/packages/benchpress/test/metric/perflog_metric_spec.ts
@@ -18,12 +18,13 @@ export function main() {
 
   function createMetric(
       perfLogs: PerfLogEvent[], perfLogFeatures: PerfLogFeatures,
-      {microMetrics, forceGc, captureFrames, receivedData, requestCount}: {
+      {microMetrics, forceGc, captureFrames, receivedData, requestCount, ignoreNavigation}: {
         microMetrics?: {[key: string]: string},
         forceGc?: boolean,
         captureFrames?: boolean,
         receivedData?: boolean,
-        requestCount?: boolean
+        requestCount?: boolean,
+        ignoreNavigation?: boolean
       } = {}): Metric {
     commandLog = [];
     if (!perfLogFeatures) {
@@ -59,6 +60,9 @@ export function main() {
     if (requestCount != null) {
       providers.push({provide: Options.REQUEST_COUNT, useValue: requestCount});
     }
+    if (ignoreNavigation != null) {
+      providers.push({provide: PerflogMetric.IGNORE_NAVIGATION, useValue: ignoreNavigation});
+    }
     return Injector.create(providers).get(PerflogMetric);
   }
 
@@ -185,6 +189,22 @@ export function main() {
            });
          }));
 
+      it('should ignore navigationStart if ignoreNavigation is set',
+         inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
+           const events = [[
+             eventFactory.markStart('benchpress0', 0), eventFactory.start('script', 4),
+             eventFactory.end('script', 6), eventFactory.instant('navigationStart', 7),
+             eventFactory.start('script', 8), eventFactory.end('script', 9),
+             eventFactory.markEnd('benchpress0', 10)
+           ]];
+           const metric = createMetric(events, null !, {ignoreNavigation: true});
+           metric.beginMeasure().then((_) => metric.endMeasure(false)).then((data) => {
+             expect(data['scriptTime']).toBe(3);
+
+             async.done();
+           });
+         }));
+
       it('should restart timing', inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
            const events = [
              [