Backed out changeset ec64ea9b1249 (bug 1360916) for failing browser_sessionStorage_size.js. r=backout

browser/components/sessionstore/SessionStore.jsm

@@ -858,8 +858,9 @@ var SessionStoreInternal = {
           return;
         }
 
-        // Update the tab's cached state.
-        // Mark the window as dirty and trigger a delayed write.
+        // Record telemetry measurements done in the child and update the tab's
+        // cached state. Mark the window as dirty and trigger a delayed write.
+        this.recordTelemetry(aMessage.data.telemetry);
         TabState.update(browser, aMessage.data);
         this.saveStateDelayed(win);
 
@@ -972,6 +973,7 @@ var SessionStoreInternal = {
         this._crashedBrowsers.delete(browser.permanentKey);
         break;
       case "SessionStore:error":
+        this.reportInternalError(data);
         TabStateFlusher.resolveAll(browser, false, "Received error from the content process");
         break;
       default:
@@ -979,6 +981,18 @@ var SessionStoreInternal = {
     }
   },
 
+  /**
+   * Record telemetry measurements stored in an object.
+   * @param telemetry
+   *        {histogramID: value, ...} An object mapping histogramIDs to the
+   *        value to be recorded for that ID,
+   */
+  recordTelemetry(telemetry) {
+    for (let histogramId in telemetry) {
+      Telemetry.getHistogramById(histogramId).add(telemetry[histogramId]);
+    }
+  },
+
   /* ........ Window Event Handlers .............. */
 
   /**
@@ -4720,6 +4734,19 @@ var SessionStoreInternal = {
     this._browserEpochs.delete(browser.permanentKey);
   },
 
+  /**
+   * Handle an error report from a content process.
+   */
+  reportInternalError(data) {
+    // For the moment, we only report errors through Telemetry.
+    if (data.telemetry) {
+      for (let key of Object.keys(data.telemetry)) {
+        let histogram = Telemetry.getHistogramById(key);
+        histogram.add(data.telemetry[key]);
+      }
+    }
+  },
+
   /**
    * Countdown for a given duration, skipping beats if the computer is too busy,
    * sleeping or otherwise unavailable.

browser/components/sessionstore/content/content-sessionStore.js

@@ -15,9 +15,6 @@ Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
 Cu.import("resource://gre/modules/Timer.jsm", this);
 Cu.import("resource://gre/modules/Services.jsm", this);
 
-XPCOMUtils.defineLazyModuleGetter(this, "TelemetryStopwatch",
-  "resource://gre/modules/TelemetryStopwatch.jsm");
-
 function debug(msg) {
   Services.console.logStringMessage("SessionStoreContent: " + msg);
 }
@@ -660,8 +657,8 @@ var SessionStorageListener = {
         }
 
         let size = this.estimateStorageSize(collected);
-        Services.telemetry.getHistogramById("FX_SESSION_RESTORE_DOM_STORAGE_SIZE_ESTIMATE_CHARS").add(size);
 
+        MessageQueue.push("telemetry", () => ({ FX_SESSION_RESTORE_DOM_STORAGE_SIZE_ESTIMATE_CHARS: size }));
         if (size > Preferences.get("browser.sessionstore.dom_storage_limit", DOM_STORAGE_MAX_CHARS)) {
           // Rather than keeping the old storage, which wouldn't match the rest
           // of the state of the page, empty the storage. DOM storage will be
@@ -829,39 +826,42 @@ var MessageQueue = {
     }
 
     let flushID = (options && options.flushID) || 0;
-    let histID = "FX_SESSION_RESTORE_CONTENT_COLLECT_DATA_MS";
+
+    let durationMs = Date.now();
 
     let data = {};
+    let telemetry = {};
     for (let [key, func] of this._data) {
-      if (key != "isPrivate") {
-        TelemetryStopwatch.startKeyed(histID, key);
-      }
-
       let value = func();
-
-      if (key != "isPrivate") {
-        TelemetryStopwatch.finishKeyed(histID, key);
-      }
-
-      if (value || (key != "storagechange" && key != "historychange")) {
+      if (key == "telemetry") {
+        for (let histogramId of Object.keys(value)) {
+          telemetry[histogramId] = value[histogramId];
+        }
+      } else if (value || (key != "storagechange" && key != "historychange")) {
         data[key] = value;
       }
     }
 
     this._data.clear();
 
+    durationMs = Date.now() - durationMs;
+    telemetry.FX_SESSION_RESTORE_CONTENT_COLLECT_DATA_LONGEST_OP_MS = durationMs;
+
     try {
       // Send all data to the parent process.
       sendAsyncMessage("SessionStore:update", {
-        data, flushID,
+        data, telemetry, flushID,
         isFinal: options.isFinal || false,
         epoch: gCurrentEpoch
       });
     } catch (ex) {
-      if (ex && ex.result == Cr.NS_ERROR_OUT_OF_MEMORY) {
-        Services.telemetry.getHistogramById("FX_SESSION_RESTORE_SEND_UPDATE_CAUSED_OOM").add(1);
-        sendAsyncMessage("SessionStore:error");
-      }
+        if (ex && ex.result == Cr.NS_ERROR_OUT_OF_MEMORY) {
+          sendAsyncMessage("SessionStore:error", {
+            telemetry: {
+              FX_SESSION_RESTORE_SEND_UPDATE_CAUSED_OOM: 1
+            }
+          });
+        }
     }
   },
 };

toolkit/components/telemetry/Histograms.json

@@ -5648,15 +5648,13 @@
     "n_buckets": 10,
     "description": "Session restore: Time to collect all window and tab data (ms)"
   },
-  "FX_SESSION_RESTORE_CONTENT_COLLECT_DATA_MS": {
-    "alert_emails": ["session-restore-telemetry-alerts@mozilla.com", "mdeboer@mozilla.com"],
-    "expires_in_version": "60",
+  "FX_SESSION_RESTORE_CONTENT_COLLECT_DATA_LONGEST_OP_MS": {
+    "alert_emails": ["session-restore-telemetry-alerts@mozilla.com"],
+    "expires_in_version": "default",
     "kind": "exponential",
-    "keyed": true,
     "high": 30000,
-    "n_buckets": 20,
-    "bug_numbers": [1360916],
-    "description": "Session restore: Duration of data collection in the content process (ms). Possible keys currently are: historychange, scroll, formdata, pageStyle, disallow, storage, storagechange."
+    "n_buckets": 10,
+    "description": "Session restore: Duration of the longest uninterruptible operation while collecting data in the content process (ms)"
   },
   "FX_SESSION_RESTORE_PRIVACY_LEVEL": {
     "alert_emails": ["session-restore-telemetry-alerts@mozilla.com"],

toolkit/components/telemetry/histogram-whitelists.json

@@ -941,6 +941,7 @@
     "FX_SESSION_RESTORE_AUTO_RESTORE_DURATION_UNTIL_EAGER_TABS_RESTORED_MS",
     "FX_SESSION_RESTORE_COLLECT_ALL_WINDOWS_DATA_MS",
     "FX_SESSION_RESTORE_COLLECT_DATA_MS",
+    "FX_SESSION_RESTORE_CONTENT_COLLECT_DATA_LONGEST_OP_MS",
     "FX_SESSION_RESTORE_CORRUPT_FILE",
     "FX_SESSION_RESTORE_DOM_STORAGE_SIZE_ESTIMATE_CHARS",
     "FX_SESSION_RESTORE_FILE_SIZE_BYTES",
@@ -1749,6 +1750,7 @@
     "MOZ_SQLITE_OTHER_READ_B",
     "CHECK_JAVA_ENABLED",
     "TRANSLATION_OPPORTUNITIES",
+    "FX_SESSION_RESTORE_CONTENT_COLLECT_DATA_LONGEST_OP_MS",
     "NEWTAB_PAGE_BLOCKED_SITES_COUNT",
     "FX_SESSION_RESTORE_NUMBER_OF_TABS_RESTORED",
     "WEAVE_START_COUNT",