bugzilla-data-medium.json

{"bugs":[{"keywords":["perf:responsiveness"],"severity":"S3","status":"ASSIGNED","priority":"P3","last_change_time":"2025-10-06T13:53:06Z","op_sys":"All","component":"Graphics: WebRender","id":1626816,"summary":"WebRender program cache / shader initialization blocks the main thread via the sync IPC message PWebRenderBridge::EnsureConnected (25ms-40ms startup penalty)","creation_time":"2020-04-02T00:26:08Z"},{"summary":"js::jit::GenerateCode spends a lot of time in malloc lock contention","id":1922073,"component":"JavaScript Engine: JIT","creation_time":"2024-10-01T18:43:40Z","severity":"S3","keywords":[],"op_sys":"Android","last_change_time":"2025-01-06T15:03:33Z","priority":"P3","status":"ASSIGNED"},{"op_sys":"All","status":"NEW","priority":"--","last_change_time":"2023-05-15T19:04:00Z","keywords":["perf"],"severity":"S3","creation_time":"2003-08-17T03:26:28Z","id":216418,"summary":"Page with lots of <pre> text (or rather: extremely deeply-nested inline tags, with lots of linebreaks) uses lots of memory in layout arenas and is slow to load","component":"Layout"},{"id":304683,"summary":"firefox struggles with large doxygen html file in nsLocalFile::GetLastModifiedTime (from imgLoader)","component":"Graphics: ImageLib","creation_time":"2005-08-15T08:01:49Z","keywords":["perf:pageload","perf:resource-use","perf:responsiveness","reproducible"],"severity":"S3","op_sys":"All","priority":"--","status":"NEW","last_change_time":"2024-09-04T13:05:12Z"},{"severity":"S3","keywords":["perf:pageload"],"last_change_time":"2023-08-23T01:33:13Z","priority":"--","status":"NEW","op_sys":"All","component":"XML","summary":"Write a new off-the-main-thread IO driver for expat","id":651049,"creation_time":"2011-04-19T08:20:35Z"},{"id":1027106,"summary":"Make ImageLib share cached imgRequests for the same SVG document even if the URI has a different ref/hash","component":"Graphics: ImageLib","creation_time":"2014-06-18T15:22:41Z","keywords":["perf:pageload","perf:resource-use","reproducible","testcase-wanted"],"severity":"S3","op_sys":"All","status":"NEW","priority":"--","last_change_time":"2025-02-09T16:16:28Z"},{"creation_time":"2014-07-13T16:33:17Z","component":"New Tab Page","id":1037984,"summary":"Website causes Firefox to completely hang because same script file is getting loaded over and over again","priority":"P2","status":"NEW","last_change_time":"2024-06-04T18:21:25Z","op_sys":"All","keywords":["csectype-dos","hang","memory-leak","perf:responsiveness","reproducible","testcase"],"severity":"S3"},{"severity":"S4","keywords":["perf:resource-use"],"op_sys":"All","last_change_time":"2025-03-27T16:27:51Z","status":"NEW","priority":"P5","summary":"Evaluate aggregating timers to reduce the number of times we wake up the CPU for serving them","id":1107626,"component":"DOM: Core & HTML","creation_time":"2014-12-04T20:16:51Z"},{"severity":"--","keywords":["memory-footprint","memory-leak","perf","perf:responsiveness","top-memory-leak"],"op_sys":"All","last_change_time":"2023-07-24T12:16:09Z","priority":"P3","status":"NEW","summary":"Thumbnail generation should have a time limit","id":1162698,"component":"New Tab Page","creation_time":"2015-05-07T20:09:26Z"},{"summary":"Session Restore generates sustained large disk traffic [meta]","id":1304389,"component":"Session Restore","creation_time":"2016-09-21T13:54:15Z","severity":"S3","keywords":["meta","perf:animation","perf:resource-use","perf:responsiveness","reproducible"],"op_sys":"All","last_change_time":"2025-12-04T06:38:11Z","status":"NEW","priority":"--"},{"severity":"S3","keywords":["perf","perf:pageload"],"op_sys":"Unspecified","last_change_time":"2022-10-11T19:06:39Z","status":"NEW","priority":"P3","summary":"Consider using FramePropertyTable less in layout","id":1348469,"component":"Layout","creation_time":"2017-03-18T03:14:39Z"},{"id":1349809,"summary":"getElevationRequired janks the parent process by doing IO on the main thread","component":"Application Update","creation_time":"2017-03-23T02:16:50Z","keywords":["perf","perf:responsiveness"],"severity":"S3","op_sys":"macOS","status":"NEW","priority":"P3","last_change_time":"2022-10-11T19:07:40Z"},{"severity":"S3","keywords":["perf:responsiveness"],"last_change_time":"2024-04-03T13:53:20Z","priority":"P3","status":"NEW","op_sys":"Unspecified","component":"Bookmarks & History","summary":"Showing the bookmarks panel is too slow the first time","id":1363131,"creation_time":"2017-05-08T18:35:31Z"},{"op_sys":"Unspecified","status":"NEW","priority":"--","last_change_time":"2025-03-24T22:09:33Z","keywords":["meta","perf","perf:responsiveness","perf:startup"],"severity":"S3","creation_time":"2017-05-10T02:24:10Z","id":1363586,"summary":"[meta] Creating the XPCOM system info service shouldn't be expensive","component":"XPCOM"},{"severity":"S3","keywords":["perf","perf:responsiveness","perf:startup"],"last_change_time":"2022-10-11T19:17:24Z","priority":"P3","status":"NEW","op_sys":"Unspecified","component":"Widget: Win32","summary":"Defer mozilla::widget::AudioSession::Start() until later in startup","id":1364091,"creation_time":"2017-05-11T14:44:03Z"},{"keywords":["perf:responsiveness","perf:startup"],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"P2","last_change_time":"2023-12-11T13:17:23Z","id":1370516,"summary":"NSS should be initialized off main thread","component":"Security: PSM","creation_time":"2017-06-06T12:51:51Z"},{"id":1374216,"summary":"Add-on icons should be in the navbar by first paint","component":"Toolbars and Customization","creation_time":"2017-06-19T08:52:46Z","keywords":["perf:frontend","perf:startup","regression","regressionwindow-wanted"],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"P3","last_change_time":"2022-10-11T19:24:38Z"},{"last_change_time":"2024-12-06T16:27:49Z","priority":"P3","status":"NEW","op_sys":"Unspecified","severity":"S3","keywords":[],"creation_time":"2017-08-08T21:56:17Z","component":"JavaScript Engine","summary":"Add ICs for slotful own-prop Xray property access (property on the expando)","id":1388538},{"keywords":["perf:resource-use"],"severity":"S3","status":"NEW","priority":"P3","last_change_time":"2022-10-11T19:42:53Z","op_sys":"macOS","component":"Audio/Video: Playback","id":1400787,"summary":"Using software video decoders (include VP9) ramps up computer fans on Macbook.","creation_time":"2017-09-18T08:13:45Z"},{"creation_time":"2017-10-07T10:11:51Z","id":1406622,"summary":"stylo: use invalidation framework to handle restyles needed in response to content insertion/removal","component":"CSS Parsing and Computation","op_sys":"Unspecified","priority":"P2","status":"NEW","last_change_time":"2022-10-11T19:47:36Z","keywords":["perf:responsiveness"],"severity":"S3"},{"component":"Tabbed Browser","id":1425887,"summary":"With tab animations disabled, closing current tab to switch to another will visibly show a blank page with spinner (causing flashing)","creation_time":"2017-12-18T17:47:35Z","keywords":["perf","perf:frontend"],"severity":"S3","status":"NEW","priority":"P3","last_change_time":"2025-11-24T20:54:46Z","op_sys":"All"},{"component":"JavaScript Engine","id":1428972,"summary":"RexBench is slower than Chrome/WebKit","creation_time":"2018-01-09T05:47:13Z","keywords":["perf"],"severity":"S3","status":"NEW","priority":"P2","last_change_time":"2025-06-11T11:06:28Z","op_sys":"Unspecified"},{"creation_time":"2018-02-21T13:15:04Z","component":"New Tab Page","id":1439892,"summary":"Activity stream initialization causes jank after receiving the sessionstore-windows-restored notification","priority":"P3","status":"NEW","last_change_time":"2024-04-03T03:06:41Z","op_sys":"Unspecified","keywords":["perf:frontend","perf:startup"],"severity":"S3"},{"component":"CSS Parsing and Computation","summary":"Try to understand why we're slower than Chrome on StyleBench \"Positional pseudo classes : Adding leaf elements: Async\" (& similar \"Removing\" measurement)","id":1443066,"creation_time":"2018-03-05T04:29:30Z","severity":"S3","keywords":["perf","perf:responsiveness"],"last_change_time":"2022-10-11T21:21:11Z","priority":"P3","status":"NEW","op_sys":"Unspecified"},{"id":1446012,"summary":"The first startup after an update does main thread I/O to update.status several times","component":"Application Update","creation_time":"2018-03-15T16:29:05Z","keywords":["perf:startup"],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"P3","last_change_time":"2022-10-11T21:23:37Z"},{"keywords":["perf"],"severity":"N/A","priority":"P5","status":"NEW","last_change_time":"2025-04-23T10:03:41Z","op_sys":"All","component":"JavaScript Engine: JIT","id":1454586,"summary":"Optimize resume point creation in IonBuilder","creation_time":"2018-04-17T08:42:34Z"},{"creation_time":"2018-04-24T20:33:58Z","component":"Networking: JAR","summary":"nsJARChannel::asyncOpen can still block","id":1456626,"last_change_time":"2025-04-15T20:34:51Z","priority":"P3","status":"NEW","op_sys":"Unspecified","severity":"S3","keywords":["perf","perf:responsiveness","perf:startup"]},{"severity":"S3","keywords":["nightly-community","perf","perf:responsiveness","regression"],"last_change_time":"2025-03-11T07:19:40Z","priority":"P3","status":"NEW","op_sys":"Windows 7","component":"Web Painting","summary":"Checkerboarding while scrollbar-dragging due to slow display list build on specific page with table layout","id":1456638,"creation_time":"2018-04-24T21:08:43Z"},{"keywords":["perf","perf:responsiveness"],"severity":"S3","op_sys":"Windows 10","priority":"P3","status":"NEW","last_change_time":"2024-02-08T23:49:09Z","id":1456964,"summary":"It takes a long time to re-layout the plaintext page when the sidebar is opening or closing until  move the mouse in the content area (with long time spent in RFindLineContaining)","component":"Layout: Block and Inline","creation_time":"2018-04-25T19:10:14Z"},{"op_sys":"Unspecified","last_change_time":"2023-09-21T15:50:42Z","status":"NEW","priority":"P2","severity":"S3","keywords":["perf:resource-use"],"creation_time":"2018-04-26T19:55:49Z","summary":"TabChild::RecvRenderLayers often results in two consecutive paints","id":1457276,"component":"DOM: Content Processes"},{"priority":"P3","status":"NEW","last_change_time":"2023-05-22T15:45:39Z","op_sys":"Unspecified","keywords":["perf","perf:resource-use","perf:responsiveness"],"severity":"S3","creation_time":"2018-05-02T18:01:37Z","component":"Bookmarks & History","id":1458634,"summary":"\"forget about this site\" in \"show all history\" blocks the main thread"},{"creation_time":"2018-06-11T20:32:18Z","component":"Layout","id":1468246,"summary":"High variability in performance testing with large images","status":"NEW","priority":"P3","last_change_time":"2022-10-11T21:41:13Z","op_sys":"Unspecified","keywords":["perf:pageload"],"severity":"S3"},{"op_sys":"All","priority":"P3","status":"NEW","last_change_time":"2022-10-11T21:43:40Z","keywords":["hang","perf:resource-use","power"],"severity":"S3","creation_time":"2018-06-25T21:14:25Z","id":1471029,"summary":"High cpu/gpu usage and hangs on page-http://telegra.ph/Telegram-X-03-26 & other pages","component":"Audio/Video: Playback"},{"component":"Security: Process Sandboxing","summary":"Optimize Windows sandbox policy construction","id":1476101,"creation_time":"2018-07-16T20:44:07Z","severity":"S3","keywords":["perf:responsiveness","perf:startup"],"last_change_time":"2022-10-11T21:47:20Z","priority":"P2","status":"NEW","op_sys":"Windows"},{"component":"CSS Parsing and Computation","id":1478953,"summary":"style.foo = bar changes are slow","creation_time":"2018-07-27T10:44:44Z","keywords":["perf:responsiveness"],"severity":"S3","priority":"P3","status":"NEW","last_change_time":"2022-10-11T21:49:50Z","op_sys":"Unspecified"},{"component":"Audio/Video: Playback","id":1481967,"summary":"100% cpu usage and high memory use on page with multiple embedded videos","creation_time":"2018-08-08T22:40:31Z","keywords":["perf:resource-use"],"severity":"S3","status":"NEW","priority":"P3","last_change_time":"2025-03-06T17:21:40Z","op_sys":"All"},{"id":1483345,"summary":"Try and re-attach NewObject stubs after GC","component":"JavaScript Engine: JIT","creation_time":"2018-08-14T19:58:58Z","keywords":[],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"P3","last_change_time":"2024-09-21T13:28:21Z"},{"keywords":[],"severity":"S3","op_sys":"macOS","priority":"P3","status":"NEW","last_change_time":"2025-01-29T17:31:27Z","id":1488435,"summary":"Significant key input delay when typing on large Google Docs","component":"JavaScript Engine","creation_time":"2018-09-04T14:10:08Z"},{"component":"JavaScript Engine: JIT","id":1490847,"summary":"[meta] Long-standing Ion Compilation Time Issues","creation_time":"2018-09-12T22:40:00Z","keywords":["meta"],"severity":"N/A","priority":"P5","status":"NEW","last_change_time":"2025-04-23T10:05:12Z","op_sys":"Unspecified"},{"id":1490849,"summary":"Off-Main-Thread Baseline Compilation","component":"JavaScript Engine: JIT","creation_time":"2018-09-12T22:46:57Z","keywords":[],"severity":"N/A","op_sys":"Unspecified","priority":"P2","status":"NEW","last_change_time":"2025-11-20T08:28:19Z"},{"op_sys":"Unspecified","last_change_time":"2025-03-06T17:21:31Z","status":"NEW","priority":"P3","severity":"S3","keywords":["perf:resource-use"],"creation_time":"2018-10-03T15:02:45Z","summary":"Horrible performance on runningworld due to media decoding","id":1496096,"component":"Audio/Video: Playback"},{"op_sys":"Android","priority":"P3","status":"NEW","last_change_time":"2024-05-03T15:18:39Z","keywords":["perf:responsiveness"],"severity":"S3","creation_time":"2018-10-12T07:38:21Z","id":1498485,"summary":"hubs.mozilla.com frame rate with an empty scene is too slow in FxR on Oculus Go","component":"JavaScript Engine"},{"id":1502334,"summary":"Reddit content is no longer displayed when scrolled (checkerboarding), with long restyles","component":"CSS Parsing and Computation","creation_time":"2018-10-26T12:54:03Z","keywords":["perf:animation","regression","reproducible","top50"],"severity":"S3","op_sys":"All","status":"NEW","priority":"--","last_change_time":"2025-03-11T08:54:07Z"},{"op_sys":"Android","status":"NEW","priority":"P2","last_change_time":"2022-10-11T22:10:59Z","keywords":["perf:pageload"],"severity":"S3","creation_time":"2018-11-06T22:12:10Z","id":1505192,"summary":"twitch.tv site loads slow compared to Chrome","component":"JavaScript Engine"},{"op_sys":"Unspecified","last_change_time":"2025-03-06T17:04:43Z","status":"NEW","priority":"P3","severity":"S3","keywords":["perf:responsiveness"],"creation_time":"2018-11-07T17:49:31Z","summary":"Getting a list of audio devices on about:support is super slow sometimes","id":1505483,"component":"Audio/Video"},{"severity":"S3","keywords":["main-thread-io","perf:responsiveness"],"last_change_time":"2024-03-20T20:46:07Z","priority":"P5","status":"NEW","op_sys":"Unspecified","component":"Graphics","summary":"graphics data gathering (and/or canvas webgl context initialization) from about:support is slow","id":1505533,"creation_time":"2018-11-07T19:32:59Z"},{"component":"DOM: Animation","id":1506765,"summary":"Do an optimization to not flush animations which are running on the compositor in various places where we call FlushPendingNotification","creation_time":"2018-11-13T04:54:48Z","keywords":["perf:responsiveness"],"severity":"S3","priority":"P3","status":"NEW","last_change_time":"2022-10-11T22:12:27Z","op_sys":"Unspecified"},{"creation_time":"2018-11-13T21:07:29Z","component":"Tabbed Browser","summary":"Try persisting chromemargin and brighttext attributes on browser windows","id":1506962,"last_change_time":"2022-10-11T22:12:38Z","priority":"P5","status":"NEW","op_sys":"Unspecified","severity":"S3","keywords":["perf:frontend","perf:responsiveness","perf:startup"]},{"op_sys":"Unspecified","last_change_time":"2023-07-24T12:22:05Z","status":"NEW","priority":"P3","severity":"S3","keywords":["parity-chrome","perf","perf:animation","perf:pageload","perf:responsiveness","regression","reproducible"],"creation_time":"2018-11-20T19:36:06Z","summary":"Firefox is very slow to render poster PDF","id":1508765,"component":"PDF Viewer"},{"priority":"P3","status":"NEW","last_change_time":"2022-10-11T22:14:24Z","op_sys":"Unspecified","keywords":["perf","perf:pageload"],"severity":"S3","creation_time":"2018-11-22T04:38:51Z","component":"DOM: Core & HTML","id":1509228,"summary":"Optimizing nsGlobalWindowOuter::NotifyContentBlockingState() seems to have an impact on pageload"},{"keywords":["perf","perf:pageload"],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"P3","last_change_time":"2022-10-11T22:19:55Z","id":1515414,"summary":"Defer GCs in background tabs/processes during pageload","component":"JavaScript: GC","creation_time":"2018-12-19T19:35:51Z"},{"component":"Graphics","id":1515473,"summary":"CPU intensive slideshow on http://thesantaclausparade.com/","creation_time":"2018-12-19T22:43:20Z","keywords":["perf","perf:responsiveness"],"severity":"S3","status":"NEW","priority":"P3","last_change_time":"2024-08-03T20:54:28Z","op_sys":"Unspecified"},{"creation_time":"2018-12-20T23:13:35Z","component":"General","summary":"[meta] reduce impact/overhead of custom element use on startup","id":1515799,"last_change_time":"2023-08-05T01:39:19Z","priority":"P3","status":"NEW","op_sys":"Unspecified","severity":"S3","keywords":["meta","perf:frontend","perf:startup"]},{"creation_time":"2018-12-27T14:05:19Z","component":"Downloads Panel","summary":"Download indicator code should use idle task and/or not load until there are downloads","id":1516525,"last_change_time":"2022-10-11T22:20:48Z","status":"NEW","priority":"P5","op_sys":"Unspecified","severity":"S3","keywords":["perf:frontend","perf:startup"]},{"creation_time":"2019-01-17T08:50:51Z","id":1520729,"summary":"jetbrains \"upsource\" file-view hangs the browser, when scrolled","component":"Layout","op_sys":"Unspecified","status":"NEW","priority":"P2","last_change_time":"2022-10-11T22:24:11Z","keywords":["perf:responsiveness"],"severity":"S3"},{"priority":"P2","status":"NEW","last_change_time":"2022-10-11T22:25:37Z","op_sys":"All","keywords":["perf:pageload"],"severity":"S3","creation_time":"2019-01-23T18:40:07Z","component":"Layout: Text and Fonts","id":1522196,"summary":"InitOtherFamilyNamesRunnable can slow down first page load and take > 100ms"},{"op_sys":"All","priority":"P3","status":"NEW","last_change_time":"2025-03-02T13:58:32Z","keywords":["meta","perf","perf:responsiveness","regression"],"severity":"S3","creation_time":"2019-01-26T00:23:18Z","id":1523028,"summary":"[meta] Performance of \"about:config\"","component":"Preferences"},{"creation_time":"2019-01-31T20:58:54Z","summary":"Twitch.tv video's (vod) freeze during playback on MacOS","id":1524384,"component":"Audio/Video: Playback","op_sys":"macOS","last_change_time":"2025-03-17T17:28:58Z","status":"NEW","priority":"P3","severity":"S3","keywords":["perf:responsiveness"]},{"component":"Web Painting","summary":"Scroll jank when mousewheel-scrolling slide thumbnails on Google Docs (with lots of time spent painting & in GetFrameForPoint)","id":1527037,"creation_time":"2019-02-11T18:16:31Z","severity":"S3","keywords":["perf:responsiveness"],"last_change_time":"2022-10-11T22:29:04Z","status":"NEW","priority":"P2","op_sys":"Unspecified"},{"severity":"S3","keywords":["meta","perf:pageload"],"last_change_time":"2025-11-21T13:11:58Z","status":"NEW","priority":"P2","op_sys":"Unspecified","component":"Networking: HTTP","summary":"[meta] Allow call of AsyncOpen and OnStart/OnStopRequest off the main thread","id":1528285,"creation_time":"2019-02-15T16:08:16Z"},{"op_sys":"Unspecified","priority":"P3","status":"NEW","last_change_time":"2023-08-05T01:38:55Z","keywords":["perf:frontend","perf:startup"],"severity":"S3","creation_time":"2019-03-11T18:25:07Z","id":1534371,"summary":"Lazy load browser.xul menus","component":"Menus"},{"creation_time":"2019-03-19T21:20:53Z","summary":"[10.14.4] Poor battery life on MacBook Pro","id":1536622,"component":"Graphics","op_sys":"macOS","last_change_time":"2023-02-01T17:22:05Z","status":"NEW","priority":"P3","severity":"S3","keywords":["perf","perf:resource-use"]},{"creation_time":"2019-03-20T07:53:47Z","summary":"Performance is slow/janky with a full complement of add-ons, restored session, opening discarded tabs","id":1536739,"component":"General","op_sys":"Unspecified","last_change_time":"2024-04-02T13:41:19Z","status":"NEW","priority":"P3","severity":"S3","keywords":["perf:responsiveness"]},{"op_sys":"Unspecified","last_change_time":"2025-03-20T13:08:13Z","priority":"--","status":"NEW","severity":"S3","keywords":["perf:resource-use"],"creation_time":"2019-03-25T17:26:55Z","summary":"Set nsThreadPool limits more intelligently","id":1538784,"component":"XPCOM"},{"component":"Graphics","id":1539266,"summary":"Running gfxPlatform::Init in the content process can take a long time","creation_time":"2019-03-26T20:57:57Z","keywords":["perf:responsiveness"],"severity":"S3","priority":"P3","status":"NEW","last_change_time":"2022-10-11T22:39:22Z","op_sys":"Unspecified"},{"op_sys":"Unspecified","priority":"P2","status":"NEW","last_change_time":"2022-10-11T22:40:24Z","keywords":["perf:responsiveness"],"severity":"S3","creation_time":"2019-03-29T19:18:26Z","id":1540226,"summary":"Brief video and audio interruptions on YouTube when tab is focused after it was in the background","component":"Graphics"},{"keywords":["main-thread-io","perf:startup"],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"P2","last_change_time":"2025-08-26T15:54:44Z","id":1541200,"summary":"Avoid nsExceptionHandler::SetupExtraData() doing main thread IO super early on startup","component":"Crash Reporting","creation_time":"2019-04-02T20:18:11Z"},{"creation_time":"2019-04-03T17:10:18Z","summary":"Evaluate whether we can stop using compatibility.ini in the common case where app compat info is in profiles.ini / installs.ini","id":1541491,"component":"Startup and Profile System","op_sys":"Unspecified","last_change_time":"2024-07-25T20:36:55Z","status":"NEW","priority":"P3","severity":"S3","keywords":["main-thread-io","perf","perf:startup"]},{"severity":"S3","keywords":["main-thread-io","perf","perf:responsiveness","perf:startup"],"op_sys":"Unspecified","last_change_time":"2022-10-11T22:41:40Z","priority":"P3","status":"NEW","summary":"Stop writing compatibility.ini piecemeal and on the main thread and on startup","id":1541494,"component":"Startup and Profile System","creation_time":"2019-04-03T17:15:49Z"},{"keywords":["main-thread-io","perf","perf:startup"],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"--","last_change_time":"2025-09-30T14:55:10Z","id":1541601,"summary":"Very very very carefully... remove channel-prefs.js and stop reading it from the main thread early on startup","component":"Startup and Profile System","creation_time":"2019-04-03T21:31:57Z"},{"component":"Performance: Navigation","id":1543776,"summary":"[meta] 5+ second delays seen while loading www.allrecipes.com on geckoview_example","creation_time":"2019-04-11T17:55:48Z","keywords":["meta","perf:pageload"],"severity":"S3","priority":"P2","status":"NEW","last_change_time":"2025-03-21T02:42:28Z","op_sys":"Unspecified"},{"severity":"S3","keywords":["main-thread-io","perf","perf:startup"],"op_sys":"Unspecified","last_change_time":"2023-05-31T19:21:00Z","priority":"--","status":"NEW","summary":"Consolidate IO for startupCache folder access","id":1544019,"component":"XPCOM","creation_time":"2019-04-12T14:40:08Z"},{"component":"Startup and Profile System","summary":"Investigate compressing omni.ja's (with lz4)","id":1544504,"creation_time":"2019-04-15T18:19:33Z","severity":"S3","keywords":["main-thread-io","perf","perf:responsiveness","perf:startup"],"last_change_time":"2022-10-11T22:44:28Z","priority":"P3","status":"NEW","op_sys":"Unspecified"},{"creation_time":"2019-04-17T15:06:25Z","summary":"Update service tries to migrate things from \"old update dir\" early on startup and does main thread IO","id":1545119,"component":"Application Update","op_sys":"Unspecified","last_change_time":"2023-06-26T23:49:36Z","status":"NEW","priority":"P5","severity":"S3","keywords":["main-thread-io","perf:startup"]},{"op_sys":"Unspecified","last_change_time":"2022-10-11T22:47:35Z","status":"NEW","priority":"P3","severity":"S3","keywords":["main-thread-io","perf","perf:startup"],"creation_time":"2019-04-30T16:38:33Z","summary":"Only prefetch the parts of XUL.dll  that we actually will need","id":1548033,"component":"Startup and Profile System"},{"keywords":["perf:pageload"],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"P3","last_change_time":"2025-03-03T21:20:28Z","id":1548539,"summary":"Stopping blocking bfcache on unconnected peerconnections","component":"WebRTC","creation_time":"2019-05-02T14:17:10Z"},{"op_sys":"Unspecified","last_change_time":"2025-04-16T14:45:56Z","priority":"--","status":"NEW","severity":"S3","keywords":["main-thread-io","perf","perf:startup"],"creation_time":"2019-05-22T16:11:19Z","summary":"Use minidump-analyzer to append Windows AV/spyware/firewall data to crashreport .extra file; add to telemetry environment data lazily","id":1553536,"component":"Crash Reporting"},{"op_sys":"Unspecified","last_change_time":"2025-08-22T15:44:10Z","priority":"P3","status":"NEW","severity":"S3","keywords":["perf:resource-use"],"creation_time":"2019-05-23T21:51:13Z","summary":"Defer initial processing by Privileged Content process at startup","id":1553980,"component":"New Tab Page"},{"status":"NEW","priority":"--","last_change_time":"2023-02-22T18:35:16Z","op_sys":"Unspecified","keywords":["main-thread-io","perf:resource-use","perf:startup"],"severity":"S3","creation_time":"2019-05-24T15:01:19Z","component":"XPCOM","id":1554200,"summary":"nsLocalFile's Clone method is too naive, should reuse more information from the original"},{"severity":"S3","keywords":["perf:pageload","perf:responsiveness"],"last_change_time":"2025-02-12T03:06:45Z","priority":"P3","status":"NEW","op_sys":"Unspecified","component":"Safe Browsing","summary":"Classifier Update should wait for an user-idle period before initiating an update","id":1554313,"creation_time":"2019-05-24T20:22:15Z"},{"severity":"S3","keywords":["main-thread-io","perf","perf:startup"],"last_change_time":"2025-12-16T16:09:55Z","priority":"P3","status":"NEW","op_sys":"Unspecified","component":"Security: PSM","summary":"Investigate linking softokn/freebl/nss thingies directly into libxul or use readahead to make actual nss initialization cheaper","id":1557378,"creation_time":"2019-06-06T15:49:16Z"},{"op_sys":"All","last_change_time":"2024-04-03T16:04:02Z","priority":"P3","status":"NEW","severity":"S3","keywords":["perf:resource-use","perf:startup"],"creation_time":"2019-07-16T15:55:54Z","summary":"When defaulting to showing about:home on startup, try to delay WebExtension process start-up until after about:home is done loading","id":1566487,"component":"General"},{"id":1568027,"summary":"WebRender performs worse on Binding of Isaac CodePen demo (svg filters/blob)","component":"Graphics: WebRender","creation_time":"2019-07-22T20:30:43Z","keywords":["perf:responsiveness"],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"P3","last_change_time":"2024-09-20T22:54:50Z"},{"op_sys":"Unspecified","last_change_time":"2025-03-21T02:42:54Z","priority":"P2","status":"NEW","severity":"S3","keywords":["perf:pageload"],"creation_time":"2019-07-30T18:44:15Z","summary":"Investigate fast first paints","id":1570090,"component":"Performance: Navigation"},{"keywords":["main-thread-io","meta","perf:responsiveness","perf:startup"],"severity":"S3","priority":"P3","status":"NEW","last_change_time":"2024-04-30T00:02:56Z","op_sys":"Windows","component":"Widget: Win32","id":1570616,"summary":"[meta] Move away from sync CoCreateInstance to RoGetAgileReference or similar (to avoid mainthread IO)","creation_time":"2019-08-01T11:28:18Z"},{"op_sys":"Unspecified","status":"NEW","priority":"P3","last_change_time":"2025-06-12T19:54:27Z","keywords":["perf:pageload"],"severity":"S3","creation_time":"2019-08-01T19:38:04Z","id":1570750,"summary":"gfxFontGroup::FindFontForChar took a lot of time during reflow","component":"Layout: Text and Fonts"},{"creation_time":"2019-08-07T18:46:11Z","component":"Performance: General","id":1572180,"summary":"68 runs 3x slower than 67 on sample script","priority":"P2","status":"NEW","last_change_time":"2022-10-11T23:10:26Z","op_sys":"Unspecified","keywords":["perf:resource-use"],"severity":"S3"},{"creation_time":"2019-09-19T18:12:52Z","component":"Networking","id":1582525,"summary":"Avoid racing 6 connections for sites known to have been HTTP2 in the past","status":"NEW","priority":"P5","last_change_time":"2022-03-02T16:34:12Z","op_sys":"Unspecified","keywords":["perf:pageload"],"severity":"N/A"},{"keywords":["perf:pageload","perf:responsiveness","reproducible","top50"],"severity":"S3","op_sys":"Android","status":"NEW","priority":"P2","last_change_time":"2025-11-07T07:18:14Z","id":1583220,"summary":"Visual metrics: Fenix is significantly slower than Chrome for the site https://cnn.com","component":"Performance: Responsiveness","creation_time":"2019-09-23T14:36:55Z"},{"component":"Performance: Responsiveness","summary":"Add normal-priority event queue delay time to Responsiveness measurements","id":1585327,"creation_time":"2019-10-01T13:25:15Z","severity":"S3","keywords":["perf:responsiveness"],"last_change_time":"2025-03-21T01:05:02Z","status":"NEW","priority":"P2","op_sys":"Unspecified"},{"keywords":["perf:frontend"],"severity":"S3","op_sys":"Unspecified","priority":"P3","status":"NEW","last_change_time":"2023-08-05T01:41:54Z","id":1597684,"summary":"Bookmarks & History: extremely slow back/forward navigation","component":"Bookmarks & History","creation_time":"2019-11-19T14:50:13Z"},{"keywords":["perf:pageload"],"severity":"S3","op_sys":"Unspecified","priority":"P3","status":"NEW","last_change_time":"2025-12-01T21:24:05Z","id":1598384,"summary":"13 seconds of jank when loading https://data.firefox.com/dashboard/hardware","component":"JavaScript Engine","creation_time":"2019-11-21T18:08:03Z"},{"creation_time":"2019-12-12T21:17:30Z","component":"DOM: Navigation","summary":"Implement caching of retired web-isolated processes for reuse in the same domain in Fission","id":1603578,"last_change_time":"2024-10-14T08:20:50Z","status":"NEW","priority":"P3","op_sys":"Unspecified","severity":"S3","keywords":["perf:pageload","reproducible"]},{"summary":"GMP thread can write to disk (to clear storage or remove plugins) at xpcom-shutdown-threads time","id":1609444,"component":"Audio/Video: GMP","creation_time":"2020-01-15T15:49:54Z","severity":"S3","keywords":["perf:responsiveness"],"op_sys":"Unspecified","last_change_time":"2022-10-11T23:50:49Z","status":"NEW","priority":"P3"},{"op_sys":"All","last_change_time":"2024-06-28T12:13:45Z","priority":"P2","status":"NEW","severity":"S3","keywords":["perf:resource-use"],"creation_time":"2020-02-06T20:58:06Z","summary":"[fission-power] Synchronize periodic background tasks (such as expiration tracker ticks) across content processes","id":1613760,"component":"Performance: General"},{"priority":"P2","status":"NEW","last_change_time":"2025-03-21T02:41:36Z","op_sys":"Android","keywords":["perf:pageload"],"severity":"S3","creation_time":"2020-02-07T04:18:58Z","component":"Performance: Navigation","id":1613824,"summary":"Apple Newsroom page takes a long time to load (30 seconds)"},{"summary":"[meta] Move all devtools UI out of the parent process into a privileged content process","id":1614096,"component":"General","creation_time":"2020-02-08T01:20:13Z","severity":"S3","keywords":["meta","perf:responsiveness","sec-want"],"op_sys":"All","last_change_time":"2025-10-28T10:43:51Z","priority":"P3","status":"NEW"},{"id":1614425,"summary":"https://www.fido.ca/ Pages load on mobile is several seconds slower than chrome","component":"Performance: 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startup","id":1638421,"component":"Telemetry","creation_time":"2020-05-15T18:19:13Z"},{"creation_time":"2020-06-10T13:56:24Z","id":1644740,"summary":"Stop painting when the window is occluded on Windows","component":"Graphics","op_sys":"Unspecified","priority":"--","status":"NEW","last_change_time":"2024-07-23T03:28:07Z","keywords":["perf:resource-use","top50"],"severity":"N/A"},{"op_sys":"Windows","priority":"P2","status":"NEW","last_change_time":"2025-03-21T01:05:16Z","keywords":["perf:responsiveness"],"severity":"S3","creation_time":"2020-06-17T17:48:18Z","id":1646449,"summary":"Background tabs stuck loading while CPU is under heavy load","component":"Performance: Responsiveness"},{"id":1650708,"summary":"Firefox takes 50% more time than Chrome to load/reload pages on Boardgamegeek","component":"Performance: Navigation","creation_time":"2020-07-06T04:12:46Z","keywords":["perf:pageload"],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"P3","last_change_time":"2025-04-21T16:54:21Z"},{"severity":"N/A","keywords":["perf:frontend","perf:startup"],"last_change_time":"2022-03-28T19:22:23Z","priority":"P3","status":"NEW","op_sys":"Unspecified","component":"General","summary":"Evaluate what things should move out of _scheduleArbitrarilyLateIdleTasks()","id":1651161,"creation_time":"2020-07-07T18:32:36Z"},{"severity":"S4","keywords":["perf:responsiveness"],"last_change_time":"2024-11-19T15:27:45Z","status":"NEW","priority":"P3","op_sys":"Unspecified","component":"JavaScript: GC","summary":"Performance issue on voice.google.com - Site can hang from seconds to minutes","id":1653088,"creation_time":"2020-07-15T20:19:35Z"},{"last_change_time":"2025-06-25T23:56:23Z","status":"NEW","priority":"P2","op_sys":"Android","severity":"S3","keywords":["perf:responsiveness"],"creation_time":"2020-07-18T16:39:27Z","component":"Graphics: CanvasWebGL","summary":"WebGL aquarium sample runs at 30 FPS on Google Pixel 2, 60 FPS on WebView/Chromium","id":1653777},{"severity":"S3","keywords":["leave-open","perf:responsiveness"],"last_change_time":"2025-11-03T12:19:39Z","status":"NEW","priority":"P3","op_sys":"Unspecified","component":"Debugger","summary":"Firefox freezes and becomes unusable on react/typescript/eval-source-map project","id":1653779,"creation_time":"2020-07-18T17:04:31Z"},{"creation_time":"2020-08-01T19:42:35Z","summary":"some games at gamee.com stutter a lot on firefox while it's smooth on chrome","id":1656709,"component":"Graphics: Canvas2D","op_sys":"Unspecified","last_change_time":"2022-03-02T16:39:47Z","status":"NEW","priority":"P3","severity":"S3","keywords":["perf:responsiveness"]},{"op_sys":"Unspecified","last_change_time":"2024-07-22T13:08:08Z","priority":"P3","status":"NEW","severity":"S3","keywords":["perf:responsiveness"],"creation_time":"2020-08-04T18:08:02Z","summary":"Janking/stuttering while scrolling on imgur (Celeron N4000) (Geminilake)","id":1657183,"component":"Graphics"},{"op_sys":"Unspecified","status":"NEW","priority":"--","last_change_time":"2023-08-14T15:04:45Z","keywords":["perf:pageload","regression","regressionwindow-wanted","reproducible","top50"],"severity":"S3","creation_time":"2020-08-14T18:12:37Z","id":1659166,"summary":"Very long reflows on Wikipedia Barack Obama page","component":"Layout: 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https://mrosd.maps.arcgis.com/apps/webappviewer/index.html","id":1661090,"component":"Graphics","creation_time":"2020-08-25T17:52:00Z"},{"creation_time":"2020-09-08T20:28:35Z","summary":"9to5google article takes 2x as much time to load as Chrome","id":1663768,"component":"Performance: Navigation","op_sys":"Unspecified","last_change_time":"2025-03-21T02:41:27Z","status":"NEW","priority":"P3","severity":"S3","keywords":["perf:pageload","reproducible"]},{"keywords":["perf:pageload","reproducible"],"severity":"S3","op_sys":"Unspecified","priority":"P2","status":"NEW","last_change_time":"2024-04-08T18:09:43Z","id":1667246,"summary":"Fenix loads apple.com 2 seconds slower than Chrome","component":"General","creation_time":"2020-09-24T22:23:03Z"},{"priority":"P3","status":"NEW","last_change_time":"2023-11-25T00:24:02Z","op_sys":"Unspecified","keywords":["perf:responsiveness"],"severity":"S3","creation_time":"2020-09-28T15:36:45Z","component":"Widget: Win32","id":1667807,"summary":"Add Telemetry to measure how long JumpLists block the main thread in the wild"},{"last_change_time":"2024-07-17T17:29:49Z","status":"NEW","priority":"P5","op_sys":"Unspecified","severity":"S4","keywords":["perf:resource-use","top50"],"creation_time":"2020-10-09T09:09:08Z","component":"Performance: General","summary":"Google Meet high energy impact on macOS 10.15.7","id":1670193},{"severity":"S3","keywords":["perf:responsiveness"],"last_change_time":"2022-10-25T15:51:21Z","status":"NEW","priority":"P3","op_sys":"Windows 10","component":"Graphics","summary":"Not responding notification from Firefox (in titlebar) when switching to a background window","id":1671859,"creation_time":"2020-10-19T01:37:21Z"},{"status":"NEW","priority":"P2","last_change_time":"2025-04-24T20:32:00Z","op_sys":"Unspecified","keywords":["nightly-community","perf:responsiveness"],"severity":"S3","creation_time":"2020-11-05T22:19:58Z","component":"Performance: Responsiveness","id":1675628,"summary":"Checkerboarding on scrolling wired.com article"},{"severity":"S3","keywords":["perf:responsiveness","regression"],"last_change_time":"2024-02-26T17:47:05Z","status":"NEW","priority":"P3","op_sys":"Unspecified","component":"Widget: Cocoa","summary":"nsCocoaWindow::GetWorkspaceID() hangs in SLSCopySpacesForWindows from SkyLight","id":1675724,"creation_time":"2020-11-06T10:14:06Z"},{"op_sys":"Unspecified","status":"NEW","priority":"--","last_change_time":"2022-08-01T12:48:55Z","keywords":[],"severity":"S3","creation_time":"2020-11-17T16:47:34Z","id":1677784,"summary":"PDF.js in Firefox slower than Chrome to load first page of large presentation","component":"PDF Viewer"},{"creation_time":"2020-12-18T11:42:24Z","id":1683300,"summary":"[meta] High CPU load (40% - 100%) caused by the top extensions loading animation on https://code.visualstudio.com/docs/","component":"Graphics: WebRender","op_sys":"All","priority":"P3","status":"NEW","last_change_time":"2025-03-11T07:12:59Z","keywords":["meta","perf","perf:resource-use","power"],"severity":"S3"},{"status":"NEW","priority":"--","last_change_time":"2024-04-04T23:59:39Z","op_sys":"Unspecified","keywords":["perf","perf:pageload","reproducible"],"severity":"S3","creation_time":"2021-01-15T16:46:01Z","component":"Print Preview","id":1686983,"summary":"The print preview takes minutes to display for pages that contain images that failed to load"},{"creation_time":"2021-01-22T03:51:18Z","component":"Performance: General","summary":"Slow appearance of article text when scrolling medium.com","id":1688140,"last_change_time":"2022-08-31T12:03:46Z","priority":"P3","status":"NEW","op_sys":"Unspecified","severity":"S3","keywords":["nightly-community"]},{"op_sys":"All","last_change_time":"2025-03-21T01:05:19Z","status":"NEW","priority":"P3","severity":"N/A","keywords":["perf:responsiveness"],"creation_time":"2021-01-26T18:47:04Z","summary":"Consider converting timestamps in PerformanceResourceTiming and PerformanceNavigationTiming on creation","id":1688943,"component":"Performance: Responsiveness"},{"component":"Graphics: WebRender","id":1688959,"summary":"Main thread hangs in SendFlushRendering if WebRender is busy","creation_time":"2021-01-26T19:38:43Z","keywords":[],"severity":"S3","priority":"--","status":"NEW","last_change_time":"2025-10-22T14:10:57Z","op_sys":"Windows"},{"creation_time":"2021-01-26T19:43:22Z","id":1688963,"summary":"WebRender initialization can block the main thread for an appreciable amount of time","component":"Graphics: 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\"ports\"","id":1693382,"creation_time":"2021-02-17T20:14:47Z"},{"id":1694417,"summary":"Slow reflow when selecting a large amount of text, on the logged-out view of GitHub's code viewer","component":"Layout: Text and Fonts","creation_time":"2021-02-23T15:30:09Z","keywords":["perf:responsiveness"],"severity":"S3","op_sys":"Unspecified","status":"NEW","priority":"--","last_change_time":"2025-11-07T07:04:04Z"},{"keywords":["perf:responsiveness","reproducible"],"severity":"S4","status":"NEW","priority":"P3","last_change_time":"2024-09-24T06:10:09Z","op_sys":"Unspecified","component":"Graphics: WebRender","id":1695273,"summary":"[NSFW] Slowness remaining on scrolling nsfw reddit after bug 1694017 is resolved","creation_time":"2021-02-26T17:26:09Z"},{"keywords":["perf","perf:responsiveness"],"severity":"--","op_sys":"Unspecified","priority":"--","status":"NEW","last_change_time":"2025-03-11T08:41:56Z","id":1696051,"summary":"The startup cache file is written to disk during shutdown with 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