HARD-EARNED PERFORMANCE LESSONS

Transcription

1 HARD-EARNED PERFORMANCE LESSONS SPEED LIMIT +1 David Rajchenbach-Teller (:Yoric) December 2014

2 OUR NEW STRATEGY 1. Make cool stuff 2. Don t make stuff uncool

3 LET S DISCUSS PERFORMANCE Responsiveness Speed Battery usage Hangs Crashes

4 BAD PERFORMANCE IS UNCOOL Knowing Fixing what needs to be fixed is very hard. performance can take years. Regressing performance is nasty. Performance is everybody s job.

5 1. LET S BUILD A FEATURE WITH PERFORMANCE

6 DESIGN FOR PERFORMANCE 1. Make it e10s 2. Make it Async 3. Make it Fast 4. Make it a good Layout citizen 5. Avoid killing the battery 6.

7 IS THAT SUFFICIENT? Hint: no

8 DON T TRUST YOUR SENSES New features need to work well on mid-range machines.

9 NOTHING REPLACES TESTING Test on cheaper computers (e.g. Asus T100 Win8 netbooks, Intel GPUs) Test But with and without e10s do not count on Nightly/Aurora/Beta users for performance testing.

10 NOTHING REPLACES BENCHMARKS Talos is your friend

11 THINGS TO DO WITH TALOS Check that you re not introducing a regression. If you are adding a smoothness-critical feature, you can add tests. (and we re here to help)

12 NOTHING REPLACES REALWORLD DATA Telemetry loves you and your dog, too

13 TELEMETRY (1) "FX_SESSION_RESTORE_STARTUP_INIT_SESSION_MS": { "expires_in_version": "never", "kind": "exponential", "high": "30000", "n_buckets": 20, "extended_statistics_ok": true, "description": "Session restore: Time it takes to prepare the data structures for restoring a session (ms)" },

14 TELEMETRY (2) initsession: function() { TelemetryStopwatch.start( FX_SESSION_RESTORE_STARTUP_INIT_SESSION_MS" );! // Do stuff! TelemetryStopwatch.finish( FX_SESSION_RESTORE_STARTUP_INIT_SESSION_MS" ); );

15 WITH TELEMETRY Already Track regressions semi-automatically. Soon Track user-visible jank. Correlate performance with hardware, add-ons, etc. Correlate performance with user sentiment.

16 WORKING WITH #PERF During the design phase, we can help: avoiding pitfalls; designing measurements and tests (Telemetry, Talos, target machines); interpreting We data; are here to transfer knowledge!

17 QUICK RECAP Performance since is your job: the design phase; nothing replaces realistic testing; nothing replaces real-world data (Telemetry). The Performance team is here to help.

18 WE WILL RETURN AFTER THESE COMMERCIALS QUESTIONS

19 2. A FEW WORDS ABOUT ASYNC TOOLING

20 WHAT ABOUT ASYNC TOOLING? Promise & Task; Sqlite.jsm & OS.File; PromiseWorker; AsyncShutdown; Async test; You probably use several of these already.

21 WRITING ASYNC CODE Use Promise and Task; You may not know it, but you need AsyncShutdown; Expose promiseinitialized from your services, for async startup; Use [Promise]Workers;

22 AVOID FileUtils and nsifile (use OS.File instead); mozistorage* (use Sqlite.jsm instead) Promise.defer (use PromiseUtils.defer or new Promise()); Uncaught rejections;

23 BE CAREFUL WITH Launch time of Workers (including OS.File Battery usage of I/O; Cost ಠ_ಠ) ; of communicating between threads; Ill-designed Shutdown. storage back-ends (including schemas);

24 ASYNC ERROR-HANDLING IS STILL AN OPEN QUESTION

25 WE WILL RETURN AFTER THESE COMMERCIALS QUESTIONS

26 3. SHUTDOWN

27 Shutdown 1. quit-application-requested 2. quit-application-granted 3. quit-application 4. profile-change-net-teardown places-shutdown places-will-closeconnection 5. profile-change-teardown 6. profile-before-change 7. xpcom-will-shutdown profile-beforechange2 xpcom-shutdownthreads Spin Spin Spin 8. xpcom-shutdown web-workersshutdown

28 What could possibly go wrong?

29 Async Shutdown

30 Waiting for clients before shutting down let barrier = new AsyncShutdown.Barrier( My Service will shut down ); let myshutdown = Task.async(function*() { yield barrier.wait(); // Now clean up });

31 Clients reacting to shutdown MyService.shutdown.addBlocker( I need to finish things before you shutdown, Task.async(function*() { // Finish cleanup }), () => ({ // Report state }) );

32 The result 1. Clear dependencies.! 2. Crash if you can t shutdown.! 3. No uncontrolled event loop spinning.! 4. Way fewer event loop spinning anyway.! 5. Detailed crash reports.

33 What s next? 1. Better customisability.! 2. C++ version (landed!)! 3. Maybe, some day, getting rid of our shutdown sequence.! 4. Better instrumentation to track down synchronous freezes during shutdown.

34 The Terminator

35 Firefox won t quit

36 What happened? Misbehaving plug-in or add-on?! Event loop spinning?! Race condition?! Something strange in a static destructor?

37 The Terminator Shutdown watchdog.! Starts at the first sign of shutdown.! Ensures that shutdown is progressing.! After ~60s without progress, crash.

38 What s next? 1. Crash stats.! 2. Telemetry.! 3. Killing without crashing.

39 WE WILL RETURN AFTER THESE COMMERCIALS QUESTIONS

40 4. ERROR-HANDLING

41 CONSOLE WARNINGS [72767] WARNING: '!compmgr', file /Users/david/Documents/Code/mc-telemetry/xpcom/glue/nsComponentManagerUtils.cpp, line 63 [72767] WARNING: dependent window created without a parent: file /Users/david/Documents/Code/mc-telemetry/toolkit/components/startup/ nsappstartup.cpp, line DOCSHELL 0x115a3e800 == 1 [pid = 72767] [id = 1] ++DOMWINDOW == 1 (0x115a1f000) [pid = 72767] [serial = 1] [outer = 0x0] ++DOMWINDOW == 2 (0x115a1ac00) [pid = 72767] [serial = 2] [outer = 0x115a1f000] [72767] WARNING: NS_ENSURE_SUCCESS(rv, nsresult::ns_error_unexpected) failed with result 0x : file /Users/david/Documents/Code/mctelemetry/extensions/cookie/nsPermissionManager.cpp, line 464 JavaScript error: file:///users/david/documents/code/mc-telemetry/obj-x86_64-apple-darwin noindex/dist/nightlydebug.app/contents/ Resources/components/nsHandlerService.js, line 891: NS_ERROR_FAILURE: Component returned failure code: 0x (NS_ERROR_FAILURE) [nsiproperties.get] JavaScript error: file:///users/david/documents/code/mc-telemetry/obj-x86_64-apple-darwin noindex/dist/nightlydebug.app/contents/ Resources/components/XULStore.js, line 66: NS_ERROR_FAILURE: Component returned failure code: 0x (NS_ERROR_FAILURE) [nsiproperties.get] [72767] WARNING: '!mlocalstore', file /Users/david/Documents/Code/mc-telemetry/dom/xul/XULDocument.cpp, line 2071 [72767] WARNING: NS_ENSURE_TRUE(startupCache) failed: file /Users/david/Documents/Code/mc-telemetry/dom/xbl/nsXBLDocumentInfo.cpp, line 237!! JavaScript strict warning: resource://gre/modules/appsutils.jsm, line 760: ReferenceError: reference to undefined property this._manifest[aprop]!! [72768] WARNING: Loaded script chrome://browser/content/places/browserplacesviews.js twice (bug ): file /Users/david/Documents/Code/ mc-telemetry/dom/xul/nsxulprototypecache.cpp, line 216 JavaScript strict warning:, line 0: TypeError: setting a property that has only a getter JavaScript strict warning:, line 0: TypeError: setting a property that has only a getter JavaScript strict warning:, line 0: TypeError: setting a property that has only a getter JavaScript strict warning:, line 0: TypeError: setting a property that has only a getter! [Parent 72768] ###!!! ASSERTION: Received an invalid TabContext from the child process. (Got an ownappid that didn't correspond to an app.): 'Error', file /Users/david/Documents/Code/mc-telemetry/dom/ipc/ContentProcessManager.cpp, line 179! JavaScript strict warning: file:///users/david/documents/code/mc-telemetry/obj-x86_64-apple-darwin noindex/dist/nightlydebug.app/ Contents/Resources/components/nsSearchService.js, line 3384: ReferenceError: reference to undefined property json._datatype

42 BROWSER CONSOLE WARNINGS Could not read chrome manifest 'file:///applications/firefoxnightly.app/contents/resources/chrome.manifest'.! JavaScript 1.7's let blocks are deprecated adb.js:810:79! JavaScript 1.7's let blocks are deprecated adb.js:838:52! Could not read chrome manifest Could not read chrome manifest 'file:///applications/firefoxnightly.app/contents/resources/browser/extensions/%7b972ce4c6-7e a ce6fd%7d/chrome.manifest'.! Warning: unrecognized command line flag -foreground! nsbrowsercontenthandler.js:670:0! ! Services.HealthReport.HealthReporter! WARN! No prefs data found.! OpenGL compositor Initialized Succesfully.! Version: 2.1 INTEL ! Vendor: Intel Inc.! Renderer: Intel Iris OpenGL Engine! FBO Texture Target: TEXTURE_2D! SessionHistory: [Exception... "Component returned failure code: 0x (NS_ERROR_FAILURE) [nsiobjectinputstream.readobject]" nsresult: "0x (NS_ERROR_FAILURE)" location: "JS frame :: resource://app/modules/sessionstore/sessionhistory.jsm :: SessionHistoryInternal.deserializeEntry :: line 417" data: no]! JavaScript 1.7's let blocks are deprecated clipboard.js:129:6! JavaScript 1.7's let blocks are deprecated clipboard.js:140:6! mutating the [[Prototype]] of an object will cause your code to run very slowly; instead create the object with the correct initial [[Prototype]] value using Object.create sync.js:112:4! Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help utils.js:37:0! not well-formed messages.json:1:1! downloadable font: maxp: bad max_zones: 0 (font-family: "FiraSans" style:normal weight:normal stretch:normal src index:1) source: resource://id-at-baku-dot-switchy/switchy/ data/fonts/firasans-light.woff fira.css:12:12! downloadable font: maxp: bad max_zones: 0 (font-family: "FiraSans" style:italic weight:bold stretch:normal src index:1) source: resource://id-at-baku-dot-switchy/switchy/ data/fonts/firasans-italic.woff fira.css:1:12! downloadable font: OS/2: bad linegap: -32 (font-family: "social" style:normal weight:normal stretch:normal src index:1) source: resource://id-at-baku-dot-switchy/switchy/ data/fonts/social.woff?-3o6kus icons.css:1:12! downloadable font: maxp: bad max_zones: 0 (font-family: "FiraSans" style:normal weight:bold stretch:normal src index:1) source: resource://id-at-baku-dot-switchy/switchy/ data/fonts/firasans-regular.woff fira.css:34:12! Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at status=new&status=unconfirmed&status=assigned&status=reopened&f1=requestees.login_name&o1=substring&v1=dteller%40mozilla.com&include_fields=id%2cpriority%2cseverity %2Csummary%2Cstatus%2Ccomponent%2Cassignee%2Clast_change_time&changed_after= T15%3A09%3A37Z. This can be fixed by moving the resource to the same domain or enabling CORS. bug! NS_ERROR_NOT_INITIALIZED: Component returned failure code: 0xc1f30001 (NS_ERROR_NOT_INITIALIZED) [nsimessagesender.sendasyncmessage] BackgroundPageThumbs.jsm:298:0! Key event not available on some keyboard layouts: key="g" modifiers="alt control" browser.xul! ! Services.Metrics.Provider.org.mozilla.addons! WARN! Add-on type without field: experiment! ! Services.Metrics.Provider.org.mozilla.addons! WARN! Add-on type without field: experiment! OpenGL compositor Initialized Succesfully.! Version: 2.1 INTEL ! Vendor: Intel Inc.! Renderer: Intel Iris OpenGL Engine! FBO Texture Target: TEXTURE_2D! NS_ERROR_NOT_INITIALIZED: Component returned failure code: 0xc1f30001 (NS_ERROR_NOT_INITIALIZED) [nsimessagesender.sendasyncmessage] BackgroundPageThumbs.jsm:298:0! "

43 REPORTING ERRORS? try { throw new TypeError( Expected a number ); } catch (ex) { Cu.reportError(ex); }

44 HOW DO WE USE THESE? Is the developer informed when there is a warning? Is there any actionable data? Is there anything useful?

45 OUR ERROR-HANDLING IS BROKEN And uncool, too.

46 UNBREAKING ERRORS Errors Test must reach the developers suites FHR? Errors No must be actionable error without a line number (preferably a stack)

47 A POSSIBLE API Warning.fail(category, error[, stack])! MOZ_WARNING_FAIL(category, error) Replaces Cu.reportError and NS_WARNING Causes all test suites to fail, with stack and message. Logged to FHR, with stack and message.

48 TESTSUITE-SIDE API Assert.whitelist.FIXME(category, regexp) // The test shouldn t cause this error, // investigation in progress.! Assert.whitelist.expected(category, regexp) // This error is normal in the test.

49 EXAMPLE statement.executeasync({ //... handleerror: function(aerror) { Warning.fail( ChromeProfileMigrator.GetHistoryResource, Async statement execution failed, aerror); } });

50 READY? SET? ASK QUESTIONS!

51 That s all Folks