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{"bugs":[{"summary":"Stop looking up GLContext symbols for every new window","component":"Graphics","keywords":["perf"],"status":"ASSIGNED","op_sys":"Unspecified","id":1341913,"creation_time":"2017-02-22T23:15:05Z","severity":"S3","priority":"P3","last_change_time":"2025-04-24T15:29:17Z"},{"severity":"S3","creation_time":"2019-01-23T21:52:44Z","last_change_time":"2025-03-21T02:42:31Z","priority":"P1","status":"ASSIGNED","keywords":["perf:pageload"],"component":"Performance: Navigation","summary":"Delayed image loading on low end ARM devices","id":1522282,"op_sys":"Android"},{"id":1631949,"op_sys":"Unspecified","summary":"Investigate merging shader cache files","status":"ASSIGNED","keywords":["perf:startup"],"component":"Graphics","priority":"P3","last_change_time":"2022-10-12T00:08:45Z","creation_time":"2020-04-21T20:52:29Z","severity":"S3"},{"keywords":["meta"],"status":"ASSIGNED","component":"Graphics: Text","summary":"[meta] Text shaping word cache affects performance on several SP3 tests (particularly TipTap)","op_sys":"Unspecified","id":2008619,"severity":"S2","creation_time":"2026-01-05T20:54:42Z","last_change_time":"2026-07-21T18:25:48Z","priority":"--"},{"summary":"Poor performance using bookmarks menu with large amounts of bookmarks.","component":"Bookmarks & History","keywords":["blocked-ux","perf"],"status":"NEW","id":486378,"op_sys":"Windows Vista","creation_time":"2009-04-01T20:00:41Z","severity":"S3","priority":"P3","last_change_time":"2023-05-16T02:23:47Z"},{"creation_time":"2009-04-29T22:35:30Z","severity":"N/A","priority":"P3","last_change_time":"2025-03-11T07:58:22Z","summary":"[meta] Implement an Asynchronous API for opening container query nodes","keywords":["main-thread-io","meta","perf","perf:frontend","perf:responsiveness"],"component":"Places","status":"NEW","id":490714,"op_sys":"All"},{"severity":"S3","creation_time":"2010-06-29T14:36:04Z","last_change_time":"2022-10-10T22:59:55Z","priority":"--","component":"Layout: Columns","status":"NEW","keywords":["perf","perf:responsiveness","testcase"],"summary":"{inc} Resizing window is slow for long list with multicol (from \"-moz-column-count: 3\" or \"column-width: 20em;\")","id":575614,"op_sys":"All"},{"last_change_time":"2025-03-11T08:46:07Z","priority":"--","severity":"S3","creation_time":"2010-11-19T15:34:28Z","op_sys":"macOS","id":613498,"status":"NEW","component":"XPConnect","keywords":["perf","perf:pageload"],"summary":"Very slow chrome to content DOM access"},{"keywords":["perf","perf:resource-use"],"status":"NEW","component":"Widget","summary":"throttle animation in completely obscured windows (virtual desktop, minimised, hidden behind other fullscreened windows)","id":646937,"op_sys":"Linux","severity":"S3","creation_time":"2011-03-31T18:37:55Z","last_change_time":"2022-10-10T23:24:13Z","priority":"P3"},{"summary":"Repeated calls to location.hash = \"#foo\" cause large amounts of disk activity","keywords":["perf","perf:responsiveness"],"component":"Places","status":"NEW","op_sys":"All","id":661590,"creation_time":"2011-06-02T18:09:59Z","severity":"S3","priority":"P3","last_change_time":"2025-09-29T14:01:38Z"},{"op_sys":"All","id":711924,"summary":"Compositing/present still hapens when the only changing parts are out of the viewport","status":"NEW","component":"Graphics: WebRender","keywords":["perf","perf:resource-use"],"priority":"--","last_change_time":"2024-04-08T16:58:41Z","creation_time":"2011-12-19T09:05:20Z","severity":"S3"},{"keywords":["perf"],"status":"NEW","component":"Graphics: Canvas2D","summary":"IE10 Test Drive: ParticleAcceleration Canvas 2D demo is slow","id":760888,"op_sys":"All","severity":"S3","creation_time":"2012-06-03T03:18:54Z","last_change_time":"2024-04-05T11:37:58Z","priority":"--"},{"priority":"P3","last_change_time":"2023-06-05T16:31:57Z","creation_time":"2012-10-19T21:25:22Z","severity":"S3","id":803709,"op_sys":"All","summary":"We appear to be copying large data URIs over and over in nsSimpleURI.","keywords":["perf:resource-use"],"component":"Networking","status":"NEW"},{"severity":"S3","creation_time":"2012-11-09T08:29:30Z","last_change_time":"2025-03-31T14:05:54Z","priority":"P3","keywords":["perf:responsiveness"],"status":"NEW","component":"PDF Viewer","summary":"Processing http://lib.tkk.fi/Dipl/2002/urn007413.pdf is slow, and its text layer is all messed up","op_sys":"Linux","id":810214},{"creation_time":"2012-12-14T13:46:12Z","severity":"S3","priority":"--","last_change_time":"2023-03-01T12:04:23Z","summary":"janky Scrolling on smartsheet.com Sheets","keywords":["perf","perf:responsiveness"],"status":"NEW","component":"CSS Parsing and Computation","op_sys":"Windows 7","id":821693},{"id":827440,"op_sys":"Windows 7","status":"NEW","component":"Graphics: ImageLib","keywords":["perf"],"summary":"nsIconChannel::AsyncOpen can block","last_change_time":"2022-11-24T06:34:31Z","priority":"--","severity":"S3","creation_time":"2013-01-07T19:06:03Z"},{"priority":"--","last_change_time":"2022-10-29T12:12:42Z","creation_time":"2013-01-08T19:17:33Z","severity":"S3","op_sys":"Windows 8","id":827937,"summary":"Opening huge mercurial long commit page freezing Firefox","component":"Layout","status":"NEW","keywords":["perf"]},{"component":"SQLite and Embedded Database Bindings","keywords":["perf:frontend","perf:responsiveness"],"status":"NEW","summary":"Firefox should abort on tryserver when executing SQL on the main thread","op_sys":"All","id":830504,"severity":"S3","creation_time":"2013-01-14T22:07:19Z","last_change_time":"2024-08-20T19:28:43Z","priority":"P3"},{"last_change_time":"2023-05-16T02:22:53Z","priority":"--","severity":"S3","creation_time":"2013-02-05T02:16:08Z","op_sys":"All","id":837989,"status":"NEW","component":"General","keywords":["main-thread-io","perf:frontend"],"summary":"Use IOUtils for gLastOpenDirectory"},{"summary":"nsFileChannel::nsFileChannel causes expensive lstats","status":"NEW","keywords":["main-thread-io","perf:responsiveness"],"component":"Networking: File","op_sys":"macOS","id":862383,"creation_time":"2013-04-16T15:29:21Z","severity":"S3","priority":"P3","last_change_time":"2024-03-27T16:10:09Z"},{"summary":"nsIOService::NewFileURI is doing main thread IO and causes jank","component":"Networking","status":"NEW","keywords":["main-thread-io","perf","perf:frontend"],"id":890712,"op_sys":"All","creation_time":"2013-07-07T15:57:11Z","severity":"S3","priority":"P3","last_change_time":"2024-04-01T16:26:36Z"},{"summary":"Polygon.com page scrolling becomes extremely slow after a while","component":"Layout","status":"NEW","keywords":["perf"],"op_sys":"All","id":914595,"creation_time":"2013-09-10T12:49:00Z","severity":"S3","priority":"--","last_change_time":"2023-07-27T07:06:57Z"},{"id":917090,"op_sys":"All","summary":"Visibility state is not updated when the browser window is obscured or on another workspace","status":"NEW","keywords":["perf:resource-use"],"component":"General","priority":"--","last_change_time":"2022-10-11T01:07:35Z","creation_time":"2013-09-17T02:34:03Z","severity":"S3"},{"summary":"Optimize GetRootPresContext() to avoid going through the viewmanager / view tree","component":"Layout","keywords":["perf"],"status":"NEW","id":984690,"op_sys":"Linux","creation_time":"2014-03-18T00:14:52Z","severity":"S3","priority":"--","last_change_time":"2025-12-02T04:57:52Z"},{"op_sys":"All","id":1023152,"summary":"Preload panel contents on hover of toolbar button","keywords":["perf:frontend"],"component":"Toolbars and Customization","status":"NEW","priority":"--","last_change_time":"2023-07-19T04:52:40Z","creation_time":"2014-06-10T10:02:00Z","severity":"S3"},{"severity":"S3","creation_time":"2014-08-02T09:50:40Z","last_change_time":"2026-05-29T15:38:01Z","priority":"P3","status":"NEW","component":"Places","keywords":["perf:frontend"],"summary":"Make bookmarks toolbar view use async openContainer","op_sys":"All","id":1047817},{"id":1097376,"op_sys":"Android","status":"NEW","keywords":["perf"],"component":"JavaScript Engine","summary":"Poor performance in Ember app Discourse","last_change_time":"2022-10-11T15:57:30Z","priority":"--","severity":"S3","creation_time":"2014-11-12T00:22:19Z"},{"priority":"P5","last_change_time":"2025-12-05T02:06:49Z","creation_time":"2015-01-06T01:55:10Z","severity":"S3","op_sys":"All","id":1118086,"summary":"[e10s] There is a delay for about 1 seconds to display <select> drop-down list with 1600+ items","status":"NEW","component":"Layout: Form 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deficient"},{"id":1213513,"op_sys":"Unspecified","component":"DOM: Animation","keywords":["perf:responsiveness"],"status":"NEW","summary":"2D canvas+HTML/CSS animation demo site broken on Firefox, works great on Chrome","last_change_time":"2023-02-19T05:13:03Z","priority":"--","severity":"S3","creation_time":"2015-10-10T00:31:34Z"},{"component":"Layout","status":"NEW","keywords":[],"summary":"On/Off opacity changes shouldn't create active layers","op_sys":"All","id":1217748,"severity":"S3","creation_time":"2015-10-23T09:20:20Z","last_change_time":"2024-09-22T12:08:26Z","priority":"--"},{"summary":"Block JavaScript parser thread when source code characters are not available","component":"JavaScript Engine","keywords":["perf"],"status":"NEW","id":1222086,"op_sys":"Unspecified","creation_time":"2015-11-05T17:44:28Z","severity":"S3","priority":"--","last_change_time":"2022-10-11T17:46:56Z"},{"id":1246410,"op_sys":"Unspecified","component":"Graphics: CanvasWebGL","keywords":["perf","regression","testcase"],"status":"NEW","summary":"Low performance of texImage2D with canvas2d and WebGL","last_change_time":"2025-04-05T10:12:20Z","priority":"P3","severity":"S3","creation_time":"2016-02-06T17:43:25Z"},{"severity":"S3","creation_time":"2016-03-18T17:34:07Z","last_change_time":"2025-03-17T20:05:29Z","priority":"--","status":"NEW","component":"Graphics: WebRender","keywords":["perf:responsiveness","reproducible"],"summary":"Firefox hangs with 100% CPU usage when scrolling on specific page","op_sys":"Unspecified","id":1257910},{"severity":"S3","creation_time":"2016-04-20T07:12:37Z","last_change_time":"2022-10-11T18:13:31Z","priority":"--","keywords":["perf"],"component":"JavaScript Engine","status":"NEW","summary":"Running jasmine is slower than Safari and Chrome","id":1265980,"op_sys":"Unspecified"},{"priority":"--","last_change_time":"2022-11-08T00:01:53Z","creation_time":"2016-06-07T13:45:20Z","severity":"S3","id":1278554,"op_sys":"Unspecified","summary":"CanvasRenderingContext2D::DrawImage takes lots of time when scrolling Google Spreadsheet","keywords":["perf"],"status":"NEW","component":"Graphics: Canvas2D"},{"id":1280802,"op_sys":"Unspecified","component":"JavaScript: GC","status":"NEW","keywords":["perf"],"summary":"Angular framework performance test spends 10% in nursery GC","last_change_time":"2024-08-11T09:37:57Z","priority":"P3","severity":"S3","creation_time":"2016-06-19T13:43:03Z"},{"creation_time":"2016-06-29T13:06:59Z","severity":"S3","priority":"P3","last_change_time":"2022-12-08T15:45:06Z","summary":"Firefox 40+ are very sluggish through x2go","component":"Graphics","keywords":["perf:responsiveness","regression"],"status":"NEW","id":1283089,"op_sys":"Linux"},{"creation_time":"2016-08-12T05:51:58Z","severity":"S3","priority":"P3","last_change_time":"2026-06-10T12:53:35Z","summary":"Try to tick refresh driver during html parsing","keywords":["perf"],"status":"NEW","component":"Layout","op_sys":"Unspecified","id":1294625},{"summary":"Measure and solve sync reflow for studying gdoc performance.","keywords":["perf"],"component":"Layout","status":"NEW","op_sys":"Unspecified","id":1296161,"creation_time":"2016-08-18T03:04:45Z","severity":"S3","priority":"P3","last_change_time":"2022-10-11T18:31:41Z"},{"last_change_time":"2026-02-17T17:22:57Z","priority":"--","severity":"S3","creation_time":"2016-10-01T23:51:50Z","id":1306925,"op_sys":"Windows 7","status":"NEW","keywords":["perf"],"component":"Widget: Win32","summary":"If you set a high Polling Rate USB port of the mouse (1000 Hz), there will be noticeable performance issues while moving tabs"},{"severity":"S3","creation_time":"2016-10-03T03:00:35Z","last_change_time":"2024-08-14T04:57:13Z","priority":"--","keywords":["perf"],"component":"General","status":"NEW","summary":"[Perf] [google docs] Firefox will get 3~9% faster when running gdoc test cases with chrome user agent","op_sys":"Linux","id":1307024},{"priority":"--","last_change_time":"2025-04-16T19:29:34Z","creation_time":"2016-10-08T00:18:22Z","severity":"--","op_sys":"Unspecified","id":1308660,"summary":"for background tabs, break refresh driver tick into multiple events off the main thread's event loop","status":"NEW","component":"Layout","keywords":["perf","perf:responsiveness"]},{"op_sys":"Windows 10","id":1316864,"summary":"Google Apps extremely slow -- scrolling, updating text, etc -- unusable","component":"JavaScript 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HTTP","keywords":["perf"],"priority":"P3","last_change_time":"2022-03-02T15:55:52Z","creation_time":"2017-02-25T04:45:01Z","severity":"S3"},{"priority":"P3","last_change_time":"2022-10-11T19:03:23Z","creation_time":"2017-02-28T23:07:56Z","severity":"S3","op_sys":"Unspecified","id":1343383,"summary":"nsIDOMWindowUtils::StartFrameTimeRecording should not use sync IPC","component":"Graphics: Layers","status":"NEW","keywords":["perf"]},{"summary":"Overpainting on Google docs","status":"NEW","keywords":["perf","perf:responsiveness"],"component":"Web Painting","op_sys":"Unspecified","id":1343538,"creation_time":"2017-03-01T15:26:14Z","severity":"S3","priority":"--","last_change_time":"2024-11-22T02:22:00Z"},{"id":1346178,"op_sys":"All","summary":"Consider compiling Ion IC code less eagerly","component":"JavaScript Engine: JIT","status":"NEW","keywords":["perf"],"priority":"P3","last_change_time":"2025-04-30T01:31:39Z","creation_time":"2017-03-10T12:17:59Z","severity":"S3"},{"summary":"Replace PVRManager::GetSensorState with lock-free shared memory structure (Eliminating message queue IPC)","status":"NEW","component":"WebVR","keywords":["perf"],"id":1346927,"op_sys":"Unspecified","creation_time":"2017-03-13T20:32:12Z","severity":"S3","priority":"--","last_change_time":"2022-10-11T19:05:40Z"},{"component":"JavaScript Engine","keywords":["perf"],"status":"NEW","summary":"Consider storing hints during syntax parse","id":1347861,"op_sys":"Unspecified","severity":"S3","creation_time":"2017-03-16T09:28:24Z","last_change_time":"2022-10-11T19:06:12Z","priority":"P5"},{"severity":"S3","creation_time":"2017-03-19T22:26:30Z","last_change_time":"2023-11-27T10:28:31Z","priority":"--","status":"NEW","keywords":["perf"],"component":"Layout","summary":"Optimize away OverflowAreasProperty more 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Restore","keywords":["perf:frontend"],"status":"NEW","id":1350569,"op_sys":"Unspecified","creation_time":"2017-03-25T15:19:03Z","severity":"S3","priority":"--","last_change_time":"2023-07-19T04:57:18Z"},{"priority":"P3","last_change_time":"2022-10-11T19:08:17Z","creation_time":"2017-03-25T21:49:47Z","severity":"S3","op_sys":"Unspecified","id":1350618,"summary":"Bad performance on Sony Horizon game page","component":"Audio/Video: Playback","status":"NEW","keywords":["perf"]},{"summary":"Add some instrumentation to find commonly added preference observers","status":"NEW","component":"General","keywords":["perf"],"id":1350749,"op_sys":"Unspecified","creation_time":"2017-03-26T21:54:08Z","severity":"S3","priority":"--","last_change_time":"2022-10-11T19:08:21Z"},{"keywords":["nightly-community","perf","perf:resource-use","power"],"component":"Performance: General","status":"NEW","summary":"Provide \"Slight/Light/Low power/Battery saving/Battery saver\" mode option","op_sys":"All","id":1351755,"severity":"--","creation_time":"2017-03-29T17:44:37Z","last_change_time":"2025-03-11T08:37:03Z","priority":"--"},{"last_change_time":"2025-04-27T11:43:06Z","priority":"P3","severity":"S3","creation_time":"2017-03-29T18:30:44Z","op_sys":"Unspecified","id":1351789,"keywords":["perf"],"status":"NEW","component":"JavaScript: GC","summary":"Add Telemetry probes for measuring garbage volume per GC"},{"summary":"Consider faster alternatives to PLDHashTable in hot Layout code paths","keywords":["perf"],"component":"Layout","status":"NEW","op_sys":"All","id":1351829,"creation_time":"2017-03-29T20:02:58Z","severity":"S3","priority":"--","last_change_time":"2022-10-11T19:09:06Z"},{"priority":"--","last_change_time":"2025-05-05T12:26:28Z","creation_time":"2017-03-29T20:09:00Z","severity":"S3","id":1351830,"op_sys":"All","summary":"Consider adding StyleDisplay() values to nsIFrame","component":"Layout","status":"NEW","keywords":["perf"]},{"last_change_time":"2022-11-02T13:08:34Z","priority":"P2","severity":"--","creation_time":"2017-03-30T20:21:31Z","id":1352205,"op_sys":"Unspecified","component":"Layout","status":"NEW","keywords":["perf","perf:resource-use"],"summary":"Avoid running the refresh driver when the page is in background"},{"status":"NEW","keywords":["meta","perf"],"component":"JavaScript: GC","summary":"[meta] Improve GC scheduling","op_sys":"Unspecified","id":1352524,"severity":"S3","creation_time":"2017-03-31T19:02:50Z","last_change_time":"2025-05-06T16:14:08Z","priority":"P3"},{"op_sys":"All","id":1353384,"summary":"Optimize GetName TypeOfNoProperty","status":"NEW","component":"JavaScript Engine: JIT","keywords":["perf"],"priority":"P3","last_change_time":"2025-02-10T18:11:27Z","creation_time":"2017-04-04T14:54:51Z","severity":"S3"},{"severity":"S3","creation_time":"2017-04-09T22:09:43Z","last_change_time":"2022-10-11T19:11:14Z","priority":"P3","component":"XPConnect","keywords":["perf"],"status":"NEW","summary":"Initialize sandbox global properties lazily","id":1354945,"op_sys":"Unspecified"},{"component":"Tabbed Browser","keywords":["perf","perf:frontend","perf:responsiveness"],"status":"NEW","summary":"Investigate preparing the next tab on mousedown on the tab close button","op_sys":"Unspecified","id":1355456,"severity":"S3","creation_time":"2017-04-11T13:02:53Z","last_change_time":"2023-07-19T04:59:14Z","priority":"P3"},{"last_change_time":"2023-05-16T02:22:12Z","priority":"P4","severity":"S3","creation_time":"2017-04-11T13:07:05Z","id":1355459,"op_sys":"Unspecified","status":"NEW","component":"General","keywords":["perf:frontend"],"summary":"The last window and the task bar item should disappear immediately on shutdown"},{"severity":"S3","creation_time":"2017-04-14T09:29:21Z","last_change_time":"2024-03-22T08:25:52Z","priority":"P3","keywords":["perf:frontend","perf:responsiveness"],"component":"Autocomplete","status":"NEW","summary":"Try avoiding layout flushes in autocomplete::_handleOverflow","op_sys":"Unspecified","id":1356532},{"keywords":["perf:resource-use"],"status":"NEW","component":"General","summary":"Rewrite AppConstants.jsm in C++","id":1356594,"op_sys":"Unspecified","severity":"S3","creation_time":"2017-04-14T16:14:15Z","last_change_time":"2022-10-11T19:12:20Z","priority":"P3"},{"last_change_time":"2024-03-22T13:34:58Z","priority":"P3","severity":"S3","creation_time":"2017-04-19T11:50:56Z","op_sys":"Unspecified","id":1357710,"keywords":["perf","perf:frontend","perf:responsiveness"],"status":"NEW","component":"Tours","summary":"Uninitializing UITour is 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