Bug 1540135 - Add a startup mochitest tracking mainthread I/O, r=Felipe.
authorFlorian Quèze <florian@queze.net>
Wed, 08 May 2019 08:56:22 +0000
changeset 534911 7785e3f08f857250cc417de04d42dbd0243b802a
parent 534910 dfcf9fbbd09fb7fb4cae5808e11b46d9b9c21184
child 534912 5b6f4c23e1dda31d20126e00311629f252cb7dca
push id2082
push userffxbld-merge
push dateMon, 01 Jul 2019 08:34:18 +0000
treeherdermozilla-release@2fb19d0466d2 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersFelipe
bugs1540135
milestone68.0a1
first release with
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
last release without
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
Bug 1540135 - Add a startup mochitest tracking mainthread I/O, r=Felipe. Differential Revision: https://phabricator.services.mozilla.com/D25392
browser/base/content/test/performance/browser.ini
browser/base/content/test/performance/browser_startup_mainthreadio.js
browser/components/tests/startupRecorder.js
--- a/browser/base/content/test/performance/browser.ini
+++ b/browser/base/content/test/performance/browser.ini
@@ -9,29 +9,34 @@ prefs =
   # representative of common startup.
   browser.migration.version=9999999
   browser.urlbar.quantumbar=true
   browser.startup.record=true
   gfx.canvas.willReadFrequently.enable=true
   # The form autofill framescript is only used in certain locales if this
   # pref is set to 'detect', which is the default value on non-Nightly.
   extensions.formautofill.available='on'
+environment =
+  MOZ_PROFILER_STARTUP=1
+  MOZ_PROFILER_STARTUP_FEATURES=js,mainthreadio
+  MOZ_PROFILER_STARTUP_ENTRIES=10000000
 support-files =
   head.js
 [browser_appmenu.js]
 skip-if = asan || debug || (os == 'win' && bits == 32) || (os == 'win' && processor == 'aarch64') # Bug 1382809, bug 1369959, Win32 because of intermittent OOM failures, bug 1533141 for aarch64
 [browser_preferences_usage.js]
 skip-if = !debug
 [browser_startup.js]
 [browser_startup_content.js]
 skip-if = !e10s
 [browser_startup_flicker.js]
 run-if = debug || devedition || nightly_build # Requires startupRecorder.js, which isn't shipped everywhere by default
 [browser_startup_hiddenwindow.js]
 skip-if = os == 'mac'
+[browser_startup_mainthreadio.js]
 [browser_tabclose_grow.js]
 [browser_tabclose.js]
 skip-if = (os == 'win') || (os == 'mac') # Bug 1488537, Bug 1531417, Bug 1497713
 [browser_tabdetach.js]
 [browser_tabopen.js]
 skip-if = (verify && (os == 'mac'))
 [browser_tabopen_squeeze.js]
 [browser_tabstrip_overflow_underflow.js]
new file mode 100644
--- /dev/null
+++ b/browser/base/content/test/performance/browser_startup_mainthreadio.js
@@ -0,0 +1,933 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* This test records I/O syscalls done on the main thread during startup.
+ *
+ * To run this test similar to try server, you need to run:
+ *   ./mach package
+ *   ./mach test --appname=dist <path to test>
+ *
+ * If you made changes that cause this test to fail, it's likely because you
+ * are touching more files or directories during startup.
+ * Most code has no reason to use main thread I/O.
+ * If for some reason accessing the file system on the main thread is currently
+ * unavoidable, consider defering the I/O as long as you can, ideally after
+ * the end of startup.
+ * If your code isn't strictly required to show the first browser window,
+ * it shouldn't be loaded before we are done with first paint.
+ * Finally, if your code isn't really needed during startup, it should not be
+ * loaded before we have started handling user events.
+ */
+
+"use strict";
+
+const { AddonManager } = ChromeUtils.import("resource://gre/modules/AddonManager.jsm");
+
+/* Set this to true only for debugging purpose; it makes the output noisy. */
+const kDumpAllStacks = false;
+
+// Shortcuts for conditions.
+const LINUX = AppConstants.platform == "linux";
+const WIN = AppConstants.platform == "win";
+const MAC = AppConstants.platform == "macosx";
+
+/* Paths in the whitelist can:
+ *  - be a full path, eg. "/etc/mime.types"
+ *  - have a prefix which will be resolved using Services.dirsvc
+ *    eg. "GreD:omni.ja"
+ *    It's possible to have only a prefix, in thise case the directory will
+ *    still be resolved, eg. "UAppData:"
+ *  - use * at the begining and/or end as a wildcard
+ *  - For Windows specific entries that require resolving the path to its
+ *    canonical form, ie. the old DOS 8.3 format, use canonicalize: true.
+ *    This is needed for stat calls to non-existent files.
+ * The folder separator is '/' even for Windows paths, where it'll be
+ * automatically converted to '\'.
+ *
+ * Specifying 'ignoreIfUnused: true' will make the test ignore unused entries;
+ * without this the test is strict and will fail if a whitelist entry isn't used.
+ *
+ * Each entry specifies the maximum number of times an operation is expected to
+ * occur.
+ * The operations currently reported by the I/O interposer are:
+ *   create/open: only supported on Windows currently. The test currently
+ *     ignores these markers to have a shorter initial whitelist.
+ *     Adding Unix support is bug 1533779.
+ *   stat: supported on all platforms when checking the last modified date or
+ *     file size. Supported only on Windows when checking if a file exists;
+ *     fixing this inconsistency is bug 1536109.
+ *   read: supported on all platforms, but unix platforms will only report read
+ *     calls going through NSPR.
+ *   write: supported on all platforms, but Linux will only report write calls
+ *     going through NSPR.
+ *   close: supported only on Unix, and only for close calls going through NSPR.
+ *     Adding Windows support is bug 1524574.
+ *   fsync: supported only on Windows.
+ *
+ * If an entry specifies more than one operation, if at least one of them is
+ * encountered, the test won't report a failure for the entry. This helps when
+ * whitelisting cases where the reported operations aren't the same on all
+ * platforms due to the I/O interposer inconsistencies across platforms
+ * documented above.
+ */
+const startupPhases = {
+  // Anything done before or during app-startup must have a compelling reason
+  // to run before we have even selected the user profile.
+  "before profile selection": [
+    { // bug 1541226
+      path: "UAppData:",
+      condition: WIN,
+      stat: 3,
+    },
+    { // bug 1541200
+      path: "UAppData:Crash Reports/InstallTime20*",
+      condition: AppConstants.MOZ_CRASHREPORTER,
+      stat: 1, // only caught on Windows.
+      read: 1,
+      write: 2,
+      close: 1,
+    },
+    { // bug 1541200
+      path: "UAppData:Crash Reports/LastCrash",
+      condition: WIN && AppConstants.MOZ_CRASHREPORTER,
+      stat: 1, // only caught on Windows.
+      read: 1,
+    },
+    { // bug 1541200
+      path: "UAppData:Crash Reports/LastCrash",
+      condition: !WIN && AppConstants.MOZ_CRASHREPORTER,
+      ignoreIfUnused: true, // only if we ever crashed on this machine
+      read: 1,
+      close: 1,
+    },
+    { // bug 1541226
+      path: "DefProfLRt.parent:",
+      condition: WIN,
+      stat: 1,
+    },
+    { // At least the read seems unavoidable for a regular startup.
+      path: "UAppData:profiles.ini",
+      condition: MAC,
+      stat: 1,
+      read: 1,
+      close: 1,
+    },
+    { // bug 1546931
+      path: "UAppData:installs.ini",
+      condition: WIN || MAC,
+      ignoreIfUnused: true, // only if a real profile exists on the system.
+      read: 1,
+      stat: 2,
+      close: 1,
+    },
+    { // At least the read seems unavoidable for a regular startup.
+      path: "UAppData:profiles.ini",
+      condition: WIN,
+      ignoreIfUnused: true, // only if a real profile exists on the system.
+      read: 1,
+      stat: 1,
+    },
+    { // bug 1541226, bug 1363586, bug 1541593
+      path: "ProfD:",
+      condition: WIN,
+      stat: 3,
+    },
+    {
+      path: "ProfLD:.startup-incomplete",
+      condition: !WIN, // Visible on Windows with an open marker
+      close: 1,
+    },
+    { // bug 1541491 to stop using this file, bug 1541494 to write correctly.
+      path: "ProfLD:compatibility.ini",
+      condition: !WIN, // Visible on Windows with an open marker
+      write: 18,
+      close: 1,
+    },
+    {
+      path: "GreD:omni.ja",
+      condition: !WIN, // Visible on Windows with an open marker
+      stat: 1,
+    },
+    { // bug 1376994
+      path: "XCurProcD:omni.ja",
+      condition: !WIN, // Visible on Windows with an open marker
+      stat: 1,
+    },
+    {
+      path: "ProfD:parent.lock",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1541603
+      path: "ProfD:minidumps",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1543746
+      path: "XCurProcD:defaults/preferences",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1544034
+      path: "ProfLDS:startupCache/scriptCache-child-current.bin",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1544034
+      path: "ProfLDS:startupCache/scriptCache-child.bin",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1544034
+      path: "ProfLDS:startupCache/scriptCache-current.bin",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1544034
+      path: "ProfLDS:startupCache/scriptCache.bin",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1544037
+      path: "ProfLDS:startupCache/startupCache." +
+             (Services.appinfo.is64Bit ? 8 : 4) + ".little",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1541601
+      path: "PrfDef:channel-prefs.js",
+      stat: 1,
+      read: 1,
+      close: 1,
+    },
+    { // bug 1543761
+      path: "GreD:chrome.manifest",
+      condition: !WIN, // Visible on Windows with an open marker
+      stat: 1,
+      close: 1,
+    },
+    { // bug 1376994, bug 1543761
+      path: "XCurProcD:chrome.manifest",
+      condition: !WIN, // Visible on Windows with an open marker
+      stat: 1,
+      close: 1,
+    },
+    { // At least the read seems unavoidable
+      path: "PrefD:prefs.js",
+      stat: 1,
+      read: 1,
+      close: 1,
+    },
+    { // bug 1543752
+      path: "PrefD:user.js",
+      stat: 1,
+      read: 1,
+      close: 1,
+    },
+    {
+      path: "*ld.so.conf*",
+      condition: LINUX,
+      ignoreIfUnused: true,
+      read: 22,
+      close: 11,
+    },
+    { // bug 1546838
+      path: "ProfD:xulstore/data.mdb",
+      condition: WIN,
+      write: 1,
+      fsync: 1,
+    },
+  ],
+
+  "before opening first browser window": [
+    { // bug 1541226
+      path: "ProfD:",
+      condition: WIN,
+      stat: 2,
+    },
+    {
+      path: "XCurProcD:blocklist.xml",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1534745
+      path: "ProfD:cookies.sqlite-journal",
+      condition: !LINUX,
+      stat: 3,
+      write: 4,
+    },
+    { // bug 1534745
+      path: "ProfD:cookies.sqlite",
+      condition: !LINUX,
+      stat: 2,
+      read: 2,
+      write: 1,
+    },
+    { // bug 1534745
+      path: "ProfD:cookies.sqlite-wal",
+      condition: WIN,
+      stat: 2,
+    },
+    { // bug 975996
+      path: "ProfD:permissions.sqlite",
+      condition: WIN || MAC,
+      fsync: 7,
+      read: 2,
+      stat: 1,
+      write: 10,
+    },
+    { // bug 975996
+      path: "ProfD:permissions.sqlite-journal",
+      condition: WIN || MAC,
+      fsync: 7,
+      stat: 26,
+      write: 38,
+    },
+    { // bug 975996
+      path: "ProfD:permissions.sqlite-wal",
+      condition: WIN,
+      stat: 20,
+    },
+    { // Seems done by OS X and outside of our control.
+      path: "*.savedState/restorecount.plist",
+      condition: MAC,
+      ignoreIfUnused: true,
+      write: 1,
+    },
+    {
+      path: "*ld.so.conf*",
+      condition: LINUX,
+      ignoreIfUnused: true,
+      read: 22,
+      close: 11,
+    },
+    { // bug 1545167
+      path: "/etc/mime.types",
+      condition: LINUX,
+      read: 3,
+      close: 3,
+    },
+    {
+      path: "UChrm:userChrome.css",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1541233
+      path: "UChrm:userContent.css",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1541246
+      path: "XREUSysExt:",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1541246
+      path: "XRESysExtDev:",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1541246
+      path: "ProfD:extensions",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1541246
+      path: "XCurProcD:extensions",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1541246
+      path: "UAppData:",
+      ignoreIfUnused: true, // sometimes before opening first browser window,
+                            // sometimes before first paint
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1546838
+      path: "ProfD:xulstore/data.mdb",
+      condition: WIN,
+      read: 1,
+    },
+  ],
+
+  // We reach this phase right after showing the first browser window.
+  // This means that any I/O at this point delayed first paint.
+  "before first paint": [
+    { // bug 1541226
+      path: "ProfD:",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1545119
+      path: "OldUpdRootD:",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1446012
+      path: "UpdRootD:updates/0/update.status",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1545123
+      path: "ProfD:pluginreg.dat",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1545123
+      path: "ProfD:pluginreg.dat.tmp",
+      stat: 1,
+      write: 64,
+      close: 1,
+    },
+    { // bug 1545123
+      path: "ProfD:plugins",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1545123
+      path: "APlugns:",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1545123
+      path: "UserPlugins.parent:",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1545123
+      path: "UserPlugins:",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1545123
+      path: "ProfD:plugins/nptest.dll",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1545123
+      path: "ProfD:plugins/npsecondtest.dll",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1545123
+      path: "ProfD:plugins/npthirdtest.dll",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1545123
+      path: "ProfD:plugins/npswftest.dll",
+      condition: WIN,
+      stat: 1,
+    },
+    {
+      path: "XREAppFeat:formautofill@mozilla.org.xpi",
+      condition: !WIN,
+      stat: 1,
+      close: 1,
+    },
+    { // bug 1545167
+      path: "/etc/mime.types",
+      condition: LINUX,
+      read: 1,
+      close: 1,
+    },
+    { // We only hit this for new profiles.
+      path: "XREAppDist:distribution.ini",
+      condition: WIN,
+      stat: 1,
+    },
+    {
+      path: "*WindowsApps/microsoft.windowscommunicationsapps*",
+      condition: WIN,
+      ignoreIfUnused: true,
+      stat: 3,
+    },
+    { // bug 1545139
+      path: "*Fonts/StaticCache.dat",
+      condition: WIN,
+      ignoreIfUnused: true, // Only on Win7
+      read: 1,
+    },
+    { // bug 1541246
+      path: "UAppData:",
+      ignoreIfUnused: true, // sometimes before opening first browser window,
+                            // sometimes before first paint
+      condition: WIN,
+      stat: 1,
+    },
+    { // Not in packaged builds; useful for artifact builds.
+      path: "GreD:ScalarArtifactDefinitions.json",
+      condition: WIN && !AppConstants.MOZILLA_OFFICIAL,
+      stat: 1,
+    },
+    { // Not in packaged builds; useful for artifact builds.
+      path: "GreD:EventArtifactDefinitions.json",
+      condition: WIN && !AppConstants.MOZILLA_OFFICIAL,
+      stat: 1,
+    },
+    { // bug 1546838
+      path: "ProfD:xulstore/data.mdb",
+      condition: MAC,
+      write: 3,
+    },
+    { // bug 1543090
+      path: "GreD:omni.ja",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1543090
+      path: "XCurProcD:omni.ja",
+      condition: WIN,
+      stat: 2,
+    },
+  ],
+
+  // We are at this phase once we are ready to handle user events.
+  // Any IO at this phase or before gets in the way of the user
+  // interacting with the first browser window.
+  "before handling user events": [
+    {
+      path: "GreD:update.test",
+      ignoreIfUnused: true,
+      condition: LINUX,
+      close: 1,
+    },
+    { // bug 1370516 - NSS should be initialized off main thread.
+      path: "ProfD:cert9.db",
+      condition: WIN,
+      read: 2,
+      stat: 2,
+    },
+    { // bug 1370516 - NSS should be initialized off main thread.
+      path: "ProfD:cert9.db",
+      condition: WIN,
+      ignoreIfUnused: true, // if canonicalize(ProfD) == ProfD, we'll use the previous entry.
+      canonicalize: true,
+      stat: 2,
+    },
+    { // bug 1370516 - NSS should be initialized off main thread.
+      path: "ProfD:cert9.db-journal",
+      condition: WIN,
+      canonicalize: true,
+      stat: 2,
+    },
+    { // bug 1370516 - NSS should be initialized off main thread.
+      path: "ProfD:cert9.db-wal",
+      condition: WIN,
+      canonicalize: true,
+      stat: 2,
+    },
+    { // bug 1370516 - NSS should be initialized off main thread.
+      path: "ProfD:pkcs11.txt",
+      condition: WIN,
+      read: 2,
+    },
+    { // bug 1370516 - NSS should be initialized off main thread.
+      path: "ProfD:key4.db",
+      condition: WIN,
+      read: 2,
+      stat: 2,
+    },
+    { // bug 1370516 - NSS should be initialized off main thread.
+      path: "ProfD:key4.db",
+      condition: WIN,
+      ignoreIfUnused: true, // if canonicalize(ProfD) == ProfD, we'll use the previous entry.
+      canonicalize: true,
+      stat: 2,
+    },
+    { // bug 1370516 - NSS should be initialized off main thread.
+      path: "ProfD:key4.db-journal",
+      condition: WIN,
+      canonicalize: true,
+      stat: 5,
+    },
+    { // bug 1370516 - NSS should be initialized off main thread.
+      path: "ProfD:key4.db-wal",
+      condition: WIN,
+      canonicalize: true,
+      stat: 5,
+    },
+    {
+      path: "XREAppFeat:webcompat-reporter@mozilla.org.xpi",
+      condition: !WIN,
+      ignoreIfUnused: true,
+      stat: 1,
+      close: 1,
+    },
+    { // bug 1003968
+      path: "XREAppDist:searchplugins",
+      condition: WIN,
+      stat: 1,
+    },
+    {
+      path: "XCurProcD:extensions",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1543090
+      path: "GreD:omni.ja",
+      condition: WIN,
+      stat: 1,
+    },
+    { // bug 1543090
+      path: "XCurProcD:omni.ja",
+      condition: WIN,
+      stat: 2,
+    },
+  ],
+
+  // Things that are expected to be completely out of the startup path
+  // and loaded lazily when used for the first time by the user should
+  // be blacklisted here.
+  "before becoming idle": [
+    {
+      path: "XREAppFeat:screenshots@mozilla.org.xpi",
+      ignoreIfUnused: true,
+      close: 1,
+    },
+    {
+      path: "XREAppFeat:webcompat-reporter@mozilla.org.xpi",
+      ignoreIfUnused: true,
+      stat: 1,
+      close: 1,
+    },
+    { // bug 1391590
+      path: "ProfD:places.sqlite-journal",
+      ignoreIfUnused: true,
+      fsync: 1,
+      stat: 4,
+      write: 2,
+    },
+    { // bug 1391590
+      path: "ProfD:places.sqlite-wal",
+      ignoreIfUnused: true,
+      stat: 4,
+      fsync: 3,
+      write: 148,
+    },
+    { // bug 1391590
+      path: "ProfD:places.sqlite-shm",
+      condition: WIN,
+      ignoreIfUnused: true,
+      stat: 1,
+    },
+    { // bug 1391590
+      path: "ProfD:places.sqlite",
+      ignoreIfUnused: true,
+      fsync: 2,
+      read: 1,
+      stat: 3,
+      write: 1310,
+    },
+    { // bug 1391590
+      path: "ProfD:favicons.sqlite-journal",
+      ignoreIfUnused: true,
+      fsync: 2,
+      stat: 7,
+      write: 7,
+    },
+    { // bug 1391590
+      path: "ProfD:favicons.sqlite-wal",
+      ignoreIfUnused: true,
+      fsync: 2,
+      stat: 7,
+      write: 15,
+    },
+    { // bug 1391590
+      path: "ProfD:favicons.sqlite-shm",
+      condition: WIN,
+      ignoreIfUnused: true,
+      stat: 2,
+    },
+    { // bug 1391590
+      path: "ProfD:favicons.sqlite",
+      ignoreIfUnused: true,
+      fsync: 3,
+      read: 4,
+      stat: 4,
+      write: 1300,
+    },
+    {
+      path: "ProfD:key4.db-journal",
+      condition: WIN,
+      canonicalize: true,
+      stat: 2,
+    },
+    {
+      path: "ProfD:key4.db-wal",
+      condition: WIN,
+      canonicalize: true,
+      stat: 2,
+    },
+    {
+      path: "ProfD:",
+      condition: WIN,
+      ignoreIfUnused: true,
+      stat: 3,
+    },
+    { // bug 1543090
+      path: "XCurProcD:omni.ja",
+      condition: WIN,
+      stat: 7,
+    },
+  ],
+};
+
+for (let name of ["d3d11layers", "d3d9video", "glcontext", "d3d11video", "wmfvpxvideo"]) {
+  startupPhases["before first paint"].push({
+    path: `ProfD:${name}.guard`,
+    ignoreIfUnused: true,
+    stat: 1,
+  });
+}
+
+function expandWhitelistPath(path, canonicalize = false) {
+  if (path.includes(":")) {
+    let [prefix, suffix] = path.split(":");
+    let [key, property] = prefix.split(".");
+    let dir = Services.dirsvc.get(key, Ci.nsIFile);
+    if (property) {
+      dir = dir[property];
+    }
+
+    if (canonicalize) {
+      path = dir.QueryInterface(Ci.nsILocalFileWin).canonicalPath;
+    } else {
+      // Resolve symLinks.
+      let dirPath = dir.path;
+      while (dir && !dir.isSymlink()) {
+        dir = dir.parent;
+      }
+      if (dir) {
+        dirPath = dirPath.replace(dir.path, dir.target);
+      }
+
+      path = dirPath;
+    }
+
+    if (suffix) {
+      path += "/" + suffix;
+    }
+  }
+  if (AppConstants.platform == "win") {
+    path = path.replace(/\//g, "\\");
+  }
+  return path;
+}
+
+function getStackFromProfile(profile, stack) {
+  const stackPrefixCol = profile.stackTable.schema.prefix;
+  const stackFrameCol = profile.stackTable.schema.frame;
+  const frameLocationCol = profile.frameTable.schema.location;
+
+  let result = [];
+  while (stack) {
+    let sp = profile.stackTable.data[stack];
+    let frame = profile.frameTable.data[sp[stackFrameCol]];
+    stack = sp[stackPrefixCol];
+    frame = profile.stringTable[frame[frameLocationCol]];
+    if (frame != "js::RunScript" && !frame.startsWith("next (self-hosted:")) {
+      result.push(frame);
+    }
+  }
+  return result;
+}
+
+function pathMatches(path, filename) {
+  path = path.toLowerCase();
+  return path == filename || // Full match
+    // Wildcard on both sides of the path
+    (path.startsWith("*") && path.endsWith("*") &&
+     filename.includes(path.slice(1, -1))) ||
+    // Wildcard suffix
+    (path.endsWith("*") && filename.startsWith(path.slice(0, -1))) ||
+    // Wildcard prefix
+    (path.startsWith("*") && filename.endsWith(path.slice(1)));
+}
+
+add_task(async function() {
+  if (!AppConstants.NIGHTLY_BUILD && !AppConstants.MOZ_DEV_EDITION && !AppConstants.DEBUG) {
+    ok(!("@mozilla.org/test/startuprecorder;1" in Cc),
+       "the startup recorder component shouldn't exist in this non-nightly/non-devedition/" +
+       "non-debug build.");
+    return;
+  }
+
+  {
+    let omniJa = Services.dirsvc.get("XCurProcD", Ci.nsIFile);
+    omniJa.append("omni.ja");
+    if (!omniJa.exists()) {
+      ok(false, "This test requires a packaged build, " +
+                "run 'mach package' and then use --appname=dist");
+      return;
+    }
+  }
+
+  let startupRecorder = Cc["@mozilla.org/test/startuprecorder;1"].getService().wrappedJSObject;
+  await startupRecorder.done;
+
+  // Add system add-ons to the whitelist dynamically.
+  // They should go in the omni.ja file (bug 1357205).
+  {
+    let addons = await AddonManager.getAddonsByTypes(["extension"]);
+    for (let addon of addons) {
+      if (addon.isSystem) {
+        startupPhases["before opening first browser window"].push({
+          path: `XREAppFeat:${addon.id}.xpi`,
+          stat: 3,
+          close: 2,
+        });
+        startupPhases["before handling user events"].push({
+          path: `XREAppFeat:${addon.id}.xpi`,
+          condition: WIN,
+          stat: 2,
+        });
+      }
+    }
+  }
+
+  // Check for main thread I/O markers in the startup profile.
+  let profile = startupRecorder.data.profile.threads[0];
+
+  let phases = {};
+  {
+    const nameCol = profile.markers.schema.name;
+    const dataCol = profile.markers.schema.data;
+
+    let markersForCurrentPhase = [];
+
+    for (let m of profile.markers.data) {
+      let markerName = profile.stringTable[m[nameCol]];
+      if (markerName.startsWith("startupRecorder:")) {
+        phases[markerName.split("startupRecorder:")[1]] = markersForCurrentPhase;
+        markersForCurrentPhase = [];
+        continue;
+      }
+
+      if (markerName != "FileIO")
+        continue;
+
+      let markerData = m[dataCol];
+      if (markerData.source == "sqlite-mainthread") {
+        continue;
+      }
+
+      let samples = markerData.stack.samples;
+      let stack = samples.data[0][samples.schema.stack];
+      markersForCurrentPhase.push({operation: markerData.operation,
+                                   filename: markerData.filename,
+                                   source: markerData.source,
+                                   stackId: stack});
+    }
+  }
+
+  for (let phase in startupPhases) {
+    startupPhases[phase] =
+      startupPhases[phase].filter(entry => !("condition" in entry) || entry.condition);
+    startupPhases[phase].forEach(entry => {
+      entry.path = expandWhitelistPath(entry.path, entry.canonicalize);
+    });
+  }
+
+  let tmpPath = expandWhitelistPath(MAC ? "TmpD:" : "/dev/shm").toLowerCase();
+  let shouldPass = true;
+  for (let phase in phases) {
+    let whitelist = startupPhases[phase];
+    info(`whitelisted paths ${phase}:\n` +
+         whitelist.map(e => {
+           let operations = Object.keys(e).filter(k => k != "path")
+                                  .map(k => `${k}: ${e[k]}`);
+           return `  ${e.path} - ${operations.join(", ")}`;
+         }).join("\n"));
+
+    let markers = phases[phase];
+    for (let marker of markers) {
+      if (marker.operation == "create/open") {
+        // TODO: handle these I/O markers once they are supported on
+        // non-Windows platforms.
+        continue;
+      }
+
+      // Convert to lower case before comparing because the OS X test slaves
+      // have the 'Firefox' folder in 'Library/Application Support' created
+      // as 'firefox' for some reason.
+      let filename = marker.filename.toLowerCase();
+
+      if (!filename) {
+        // We are still missing the filename on some mainthreadio markers,
+        // these markers are currently useless for the purpose of this test.
+        continue;
+      }
+
+      if (!WIN) {
+        if (filename == "/dev/urandom") {
+          continue;
+        }
+
+        // Ignore I/O due to IPC. This doesn't really touch the disk.
+        if (filename.startsWith(tmpPath + "/org.chromium.")) {
+          continue;
+        }
+      }
+
+      let expected = false;
+      for (let entry of whitelist) {
+        if (pathMatches(entry.path, filename)) {
+          entry[marker.operation] = (entry[marker.operation] || 0) - 1;
+          entry._used = true;
+          expected = true;
+          break;
+        }
+      }
+      if (!expected) {
+        record(false,
+               `unexpected ${marker.operation} on ${marker.filename} ${phase}`,
+               undefined,
+               "  " + getStackFromProfile(profile, marker.stackId).join("\n  "));
+        shouldPass = false;
+      }
+      info(`(${marker.source}) ${marker.operation} - ${marker.filename}`);
+      if (kDumpAllStacks) {
+        info(getStackFromProfile(profile, marker.stackId).map(f => "  " + f)
+                                                         .join("\n"));
+      }
+    }
+
+    for (let entry of whitelist) {
+      for (let op in entry) {
+        if (["path", "condition", "canonicalize", "ignoreIfUnused", "_used"].includes(op)) {
+          continue;
+        }
+        let message = `${op} on ${entry.path} `;
+        if (entry[op] == 0) {
+          message += "as many times as expected";
+        } else if (entry[op] > 0) {
+          message += `allowed ${entry[op]} more times`;
+        } else {
+          message += `${entry[op] * -1} more times than expected`;
+        }
+        ok(entry[op] >= 0, `${message} ${phase}`);
+      }
+      if (!("_used" in entry) && !entry.ignoreIfUnused) {
+        ok(false, `unused whitelist entry ${phase}: ${entry.path}`);
+      }
+    }
+  }
+
+  if (shouldPass) {
+    ok(shouldPass, "No unexpected main thread I/O during startup");
+  } else {
+    const filename = "startup-mainthreadio-profile.json";
+    let path = Cc["@mozilla.org/process/environment;1"]
+                 .getService(Ci.nsIEnvironment)
+                 .get("MOZ_UPLOAD_DIR");
+    let encoder = new TextEncoder();
+    let profilePath = OS.Path.join(path, filename);
+    await OS.File.writeAtomic(profilePath,
+                              encoder.encode(JSON.stringify(startupRecorder.data.profile)));
+    ok(false,
+       "Found some unexpected main thread I/O during startup; profile uploaded in " +
+       filename);
+  }
+});
--- a/browser/components/tests/startupRecorder.js
+++ b/browser/components/tests/startupRecorder.js
@@ -58,16 +58,17 @@ startupRecorder.prototype = {
   classID: Components.ID("{11c095b2-e42e-4bdf-9dd0-aed87595f6a4}"),
 
   QueryInterface: ChromeUtils.generateQI([Ci.nsIObserver]),
 
   record(name) {
     if (!Services.prefs.getBoolPref("browser.startup.record", false))
       return;
 
+    Services.profiler.AddMarker("startupRecorder:" + name);
     this.data.code[name] = {
       components: Cu.loadedComponents,
       modules: Cu.loadedModules,
       services: Object.keys(Cc).filter(c => {
         try {
           return Cm.isServiceInstantiatedByContractID(c, Ci.nsISupports);
         } catch (e) {
           return false;
@@ -158,18 +159,28 @@ startupRecorder.prototype = {
         win.removeEventListener("MozAfterPaint", afterPaintListener);
         win = null;
         this.data.frames = paints;
         this.data.prefStats = {};
         if (AppConstants.DEBUG) {
           Services.prefs.readStats((key, value) => this.data.prefStats[key] = value);
         }
         paints = null;
-        this._resolve();
-        this._resolve = null;
+
+
+        Services.profiler.getProfileDataAsync().then(profileData => {
+          this.data.profile = profileData;
+          // There's no equivalent StartProfiler call in this file because the
+          // profiler is started using the MOZ_PROFILER_STARTUP environment
+          // variable in browser/base/content/test/performance/browser.ini
+          Services.profiler.StopProfiler();
+
+          this._resolve();
+          this._resolve = null;
+        });
       });
     } else {
       const topicsToNames = {
         "profile-do-change": "before profile selection",
         "toplevel-window-ready": "before opening first browser window",
       };
       topicsToNames[firstPaintNotification] = "before first paint";
       this.record(topicsToNames[topic]);