--- a/testing/talos/talos/talos-powers/components/TalosPowersService.js
+++ b/testing/talos/talos/talos-powers/components/TalosPowersService.js
@@ -117,16 +117,17 @@ TalosPowersService.prototype = {
         let encoder = new TextEncoder();
         let array = encoder.encode(JSON.stringify(profile));
 
         OS.File.writeAtomic(profileFile, array, {
           tmpPath: profileFile + ".tmp",
         }).then(() => {
           Services.profiler.StopProfiler();
           resolve();
+          Services.obs.notifyObservers(null, "talos-profile-gathered");
         });
       }, (error) => {
         Cu.reportError("Failed to gather profile: " + error);
         // FIXME: We should probably send a message down to the
         // child which causes it to reject the waiting Promise.
         reject();
       });
     });

--- a/testing/talos/talos/talos-powers/content/TalosParentProfiler.js
+++ b/testing/talos/talos/talos-powers/content/TalosParentProfiler.js
@@ -192,10 +192,23 @@ var TalosParentProfiler;
         // If marker is omitted, just use the test name
         if (!marker) {
           marker = currentTest;
         }
 
         TalosPowers.profilerMarker(marker);
       }
     },
+
+    afterProfileGathered() {
+      if (!initted) {
+        return Promise.resolve();
+      }
+
+      return new Promise(resolve => {
+        Services.obs.addObserver(function onGathered() {
+          Services.obs.removeObserver(onGathered, "talos-profile-gathered");
+          resolve();
+        }, "talos-profile-gathered");
+      });
+    }
   };
 })();

--- a/testing/talos/talos/test.py
+++ b/testing/talos/talos/test.py
@@ -301,17 +301,17 @@ class tabpaint(PageloaderTest):
 @register_test()
 class tps(PageloaderTest):
     """
     Tests the amount of time it takes to switch between tabs
     """
     extensions = '${talos}/tests/tabswitch/tabswitch-signed.xpi'
     tpmanifest = '${talos}/tests/tabswitch/tps.manifest'
     tppagecycles = 5
-    gecko_profile_entries = 1000000
+    gecko_profile_entries = 5000000
     tploadnocache = True
     preferences = {
         'addon.test.tabswitch.urlfile': os.path.join('${talos}',
                                                      'tests',
                                                      'tp5o.html'),
         'addon.test.tabswitch.webserver': '${webserver}',
         'addon.test.tabswitch.maxurls': -1,
     }

--- a/testing/talos/talos/tests/tabswitch/bootstrap.js
+++ b/testing/talos/talos/tests/tabswitch/bootstrap.js
@@ -201,41 +201,38 @@ function switchToTab(tab) {
 
   if (browser.isRemoteBrowser) {
     return Task.spawn(function*() {
       // The multi-process case requires that we load our utility script
       // inside the content, since it's the content that will hear a MozAfterPaint
       // once the content is presented to the user.
       yield loadTPSContentScript(browser);
       let start = Math.floor(window.performance.timing.navigationStart + window.performance.now());
-      TalosParentProfiler.resume("start (" + start + "): " + browser.currentURI.spec);
 
       // We need to wait for the TabSwitchDone event to make sure
       // that the async tab switcher has shut itself down.
       let switchDone = waitForTabSwitchDone(browser);
       // Set up our promise that will wait for the content to be
       // presented.
       let finishPromise = waitForContentPresented(browser);
       // Finally, do the tab switch.
       gBrowser.selectedTab = tab;
 
       yield switchDone;
       let finish = yield finishPromise;
-      TalosParentProfiler.mark("end (" + finish + ")");
       return finish - start;
     });
   }
 
   return Task.spawn(function*() {
     let win = browser.ownerGlobal;
     let winUtils = win.QueryInterface(Ci.nsIInterfaceRequestor)
                       .getInterface(Ci.nsIDOMWindowUtils);
 
     let start = Math.floor(window.performance.timing.navigationStart + window.performance.now());
-    TalosParentProfiler.resume("start (" + start + "): " + browser.currentURI.spec);
 
     // There is no async tab switcher for the single-process case,
     // but tabbrowser.xml will still fire this once the updateCurrentBrowser
     // method runs.
     let switchDone = waitForTabSwitchDone(browser);
     // Do our tab switch
     gBrowser.selectedTab = tab;
     // Because the above tab switch is synchronous, we know that the
@@ -245,17 +242,16 @@ function switchToTab(tab) {
 
     yield switchDone;
 
     // Now we'll wait for content to be presented. Because
     // this is the single-process case, we pass the last transaction
     // id that we got so that we don't get any intermediate MozAfterPaint's
     // that might fire before web content is shown.
     let finish = yield waitForContentPresented(browser, lastTransactionId);
-    TalosParentProfiler.mark("end (" + finish + ")");
     return finish - start;
   });
 }
 
 /**
  * For some <xul:browser>, find the <xul:tabbrowser> associated with it,
  * and wait until that tabbrowser has finished a tab switch. This function
  * assumes a tab switch has started, or is about to start.
@@ -415,17 +411,19 @@ function test(window) {
       // content processes, so we cannot do this at the manifest level.
       yield switchToTab(tab);
       yield switchToTab(initialTab);
     }
 
     for (let tab of tabs) {
       gBrowser.moveTabTo(tab, 1);
       yield forceGC(win, tab.linkedBrowser);
+      TalosParentProfiler.resume("start: " + tab.linkedBrowser.currentURI.spec);
       let time = yield switchToTab(tab);
+      TalosParentProfiler.pause("finish: " + tab.linkedBrowser.currentURI.spec);
       dump(`${tab.linkedBrowser.currentURI.spec}: ${time}ms\n`);
       times.push(time);
       yield switchToTab(initialTab);
     }
 
     let output = "<!DOCTYPE html>" +
                  '<html lang="en">' +
                  "<head><title>Tab Switch Results</title></head>" +
@@ -438,29 +436,27 @@ function test(window) {
     }
     output += "</table></body></html>";
     dump("total tab switch time:" + time + "\n");
 
     let resultsTab = win.gBrowser.loadOneTab(
       "data:text/html;charset=utf-8," + encodeURIComponent(output), {
       triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal(),
     });
-    let pref = Services.prefs.getBoolPref("browser.tabs.warnOnCloseOtherTabs");
-    if (pref)
-      Services.prefs.setBoolPref("browser.tabs.warnOnCloseOtherTabs", false);
-    win.gBrowser.removeAllTabsBut(resultsTab);
-    if (pref)
-      Services.prefs.setBoolPref("browser.tabs.warnOnCloseOtherTabs", pref);
+
+    win.gBrowser.selectedTab = resultsTab;
 
     remotePage.sendAsyncMessage("tabswitch-test-results", {
       times,
       urls: testURLs,
     });
 
-    win.close();
+    TalosParentProfiler.afterProfileGathered().then(() => {
+      win.close();
+    });
   });
 }
 
 function unloadFromWindow(window) {
   if (!window)
     return;
   let toolsMenu = window.document.getElementById("menu_ToolsPopup");
   if (!toolsMenu)

--- a/testing/talos/talos/tests/tabswitch/content/test.html
+++ b/testing/talos/talos/tests/tabswitch/content/test.html
@@ -2,16 +2,17 @@
   <head>
     <script>
       function do_test(override) {
         if (override || document.location.hash.indexOf("#auto") == 0) {
           sendAsyncMessage("tabswitch-do-test");
           addMessageListener("tabswitch-test-results", function onMessage(msg) {
             let data = msg.data;
             content.tpRecordTime(data.times.join(","), 0, data.urls.join(","));
+            sendAsyncMessage("tabswitch-test-results-reported");
           });
         }
       }
     </script>
   </head>
   <body onload="do_test(false)">
     Hello Talos!
   </body>