Platform/GFX/perf triage

The page contains a breakdown of performance related bugs and tasks for WebRender.

Bugzilla tree view of the wr-perf bugs: https://bugzilla.mozilla.org/showdependencytree.cgi?id=1477376&hide_resolved=1

To determine in which category a performance issue fits in a good source of information is to set the pref gfx.webrender.debug.profiler-ui to "Frame stats,Time graphs, ,GPU". Also set "gfx.webrender.debug.profiler" and "gfx.webrender.debug.gpu-time-queries" to true. this should be enough to tell in which stage of the rendering pipeline the issue is. Then set the profiler ui pref to more specific counters to continue investigating (see the list of profile counters in profiler.rs).

High priority bugs

Metabug: wr-perf-p1

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1664478	Blend modes and other effects on a single image force an extra intermediate target		P2
enhancement	1404477	Chrome repaints cause rebuilds of the entire browser scene		P3
defect	1595680	Slightly different values in display lists causing extra picture cache invalidations.		P3
defect	1595909	Image masks with different keys being added during scrolling		P3

4 Total; 4 Open (100%); 0 Resolved (0%); 0 Verified (0%);

CPU time

Frame building

useful prefs:

• gfx.webrender.debug.profiler-ui: "Frame times"

Metabug: wr-frame-building

A few common themes:

• Many vector allocations add up to occupying a lot of the total frame building time.
• HashMap operations are also showing up.
• Removing redundant work or moving it to scene building can help a lot (for example Glenn's work on clipping).
• Some pages have a very high primitive count. Anything that can help amortize how costs scale with prim count helps.
• Timings tend to spike, so it's best to look at maximum times instead of averages. Spikes tend to line up with scene builds.

See also

• Glenn's plans/ongoing work related to frame building improvement

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1562433	Very high CPU utilization from pulsating animation		P2
defect	1611199	Batching is too slow when there are many primitives		P3
defect	1611908	A lot of time spent managing primitive dependencies during frame building		P3
enhancement	1613053	Simplify WebRender's internal storage of clip chains		P3
defect	1480964	With WR, Scrolling on maze solver page is janky. Non-WR is smooth (WR scrolling is not async enough)		P3
task	1613067	Investigate using cluster dependencies to skip visibility on some clusters		P3
defect	1512789	Scrolling inside the kangax table has high latency (Lots of time spent in parent process waiting for APZC)		P3
enhancement	1628665	Pack all four subpx positioned versions of glyphs together		P3
enhancement	1525061	CSS cursor animation dimming opacity causes 20% CPU utilisation with WebRender		P3
enhancement	1641704	Investigate update_visibility overhead & prepare_primitives		P3
enhancement	1650378	Skip frame building if the only changes in the frame are external images.		P3
defect	1587475	Page faults and Lock contention on the render backend from memory allocations		P3
enhancement	1651018	Better primitive cluster culling		P3
enhancement	1587906	Track WR frame building performance separately from the scene building		P3
enhancement	1654779	Further reduce the amount of allocations in set_param_and_get_batch	Nicolas Silva [:nical]	P3
defect	1596046	A lot of vector allocations during frame building		P3
task	1685831	Reduce the cost from checking whether glyphs were evicted by the texture cache		P3
defect	1596054	picture::TileNode::update_dirty_rects sometimes is high in profiles		P3
defect	1700284	CSS pulse animation cause a ~25% CPU load of Firefox		P3
enhancement	1611134	Process primitives by types instead of always in z-order		P3
task	1611145	Remove (most of) the primitive segmentation		P3
enhancement	1611153	Per-cluster GPU data allocation		P3
task	1604670	Switch webrender math to use intrinsics		P4
enhancement	1424579	coinmarketcap.com uses a lot more CPU with WebRender than without		P5
defect	1493359	https://lab.hakim.se/domtree/ is slower with WR		P5
enhancement	1628530	[metabug] Scene/frame building performance improvements	Glenn Watson [:gw]	--
defect	1647903	Scrolling https://github.com/servo/pathfinder/pull/350/files is a bad time		--
defect	1707796	Choppy scrolling on https://gotofitnessclub.com/		--

28 Total; 28 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Scene building

Metabug: wr-scene-building

Full Query

Type	ID	Summary	Assigned to	Priority
enhancement	1404477	Chrome repaints cause rebuilds of the entire browser scene		P3
defect	1508116	4-5ms spent scene building new Gmail (scene building is too slow)		P3
defect	1582621	Scene building takes too long (> 7ms) on the MotionMark 1.1 Multiply benchmark		P3
enhancement	1631756	Build separate pipelines for the content and UI and stitch them up during frame building		P3
enhancement	1648091	A lot of time spent reallocating vectors during scene building	Nicolas Silva [:nical]	P3
enhancement	1654305	Avoid allocations in ClipStore::push_clip_root	Nicolas Silva [:nical]	P3
enhancement	1720517	Avoid scene building for JS-controlled transform changes in the browser chrome		P3
defect	1493359	https://lab.hakim.se/domtree/ is slower with WR		P5

8 Total; 8 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Renderer (Driver & ANGLE overhead)

Metabug: wr-renderer

Useful prefs:

• gfx.webrender.debug.profiler-ui: "Frame stats,#Renderer,Renderer graphs"

Full Query

Type	ID	Summary	Assigned to	Priority
task	1660498	Investigate deferring texture deletion		P2
defect	1652511	Scrolling on https://www.aspyredesign.com/ is extremely janky (with lots of time spent in painting)		P3
defect	1657183	Janking/stuttering while scrolling on imgur (Celeron N4000) (Geminilake)		P3
defect	1659348	Heavy janking while doing page up/down on windows101tricks.com		P3
defect	1659518	Heavy janking while doing page up/down on bleepingcomputer with ANGLE		P3
enhancement	1660116	Interleave frame building and command submission		P3
defect	1660148	Janking while touchpad scrolling roboticsthroughsciencefiction page		P3
defect	1660159	Bad janking when touchpad scrolling on moneycontrol.com		P3
defect	1700284	CSS pulse animation cause a ~25% CPU load of Firefox		P3
enhancement	1701986	Share and reuse Direct composition surfaces between multiple windows		P3
task	1724129	https://codepen.io/trangthule/pen/vYmpNYR is very slow	Glenn Watson [:gw]	--
enhancement	1647080	WebRender/WR: Scrolling hangs shortly on purecss-francine	Glenn Watson [:gw]	--
defect	1674692	Slow page building while scrolling on deusex.fandom.com		--
enhancement	1678265	A lot of time spent in SwapBuffer on https://eteam-eteam.4flow.cloud/#		--
enhancement	1685261	Use a 2d texture atlas for picture cache tiles		--

15 Total; 15 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Texture/Buffer uploads

Metabug: texture-upload-perf

Useful prefs:

• gfx.webrender.debug.profiler-ui: "#GPU cache upload,#Texture cache update,#Texture uploads,#Texture uploads mem,#Rasterized glyphs,#Rasterized blob tiles"

See also:

• Meeting notes about the art and craft of uploading textures

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1478125	Texture upload performance could be better on Windows	Jeff Muizelaar [:jrmuizel]	P3
defect	1558677	Makepad scrolling is slow with WebRender		P3
task	1567511	Very noisy GPU times		P3
enhancement	1729328	Avoid copying images row by row in texture uploads	Nicolas Silva [:nical]	P3
enhancement	1732726	Use PBO uploads on Windows	Nicolas Silva [:nical]	P3
defect	1573113	https://propjockey.github.io/DOMinion-build-demo/ breaks webrender		P3
defect	1598789	Terrible scrolling performance in portions of taskcluster log		P3
defect	1599558	Video texture upload still runs into format conversion	Dzmitry Malyshau [:kvark]	P3
defect	1611582	Scrolling on myheritage.com is very laggy with WebRender		P3
defect	1628736	Slow scrolling performance on large changeset on hg.mozilla.org (VBO upload)		P3
defect	1676528	Scrolling apple.com significantly slower with WebRender on 2018 MacBook Air		P3
defect	1683354	[Bug] Scrolling stutter on gadgets.ndtv.com website		P3
defect	1699261	[Bug] choppy scrolling on https://www.deutsche-rentenversicherung.de		P3
defect	1719169	Scrolling past images makes scrolling choppy		P4
defect	1521265	Slow Frames detected on Slurpee Canada home page (canvas perf)		P5
defect	1707796	Choppy scrolling on https://gotofitnessclub.com/		--
enhancement	1711062	Scrolling on https://www.blog.google/products/chrome/manage-tabs-with-google-chrome/ is janky near the bottom of the page (animated images)		--
defect	1715059	Slow animation at https://discord.com/hypesquad		--
task	1724129	https://codepen.io/trangthule/pen/vYmpNYR is very slow	Glenn Watson [:gw]	--
defect	1736108	Zooming https://www.bia.gov/sites/bia.gov/files/assets/public/webteam/pdf/idc1-028635.pdf is slow in Firefox		--
defect	1647908	Bad performance on https://questdb.io/ from animated background svg		--
defect	1672182	Bad performance on https://gatewayusa.com/products.html		--

22 Total; 22 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Batching

Metabug: wr-batching

Performance issues caused by high amounts of draw calls. 100 draw calls per frames is a reasonable amount (not a hard limit). Multiple hundreds, however, tend to cause excessive CPU usage in the renderer.

Useful prefs:

• gfx.webrender.debug.profiler-ui: "#Draw calls"

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1573113	https://propjockey.github.io/DOMinion-build-demo/ breaks webrender		P3
defect	1580864	Janky scrolling with interactive map		P3
task	1585374	Investigate batching algorithm improvements	Nicolas Silva [:nical]	P3
task	1615613	Unify the text and brush shader infrastructures	Nicolas Silva [:nical]	P3
task	1622226	Pack more images in the shared texture cache		P3
enhancement	1624272	Decouple texture cache storage and batching		P3
defect	1637580	Very poor javascript + SVG animation performance		P3
defect	1651753	Janky WebRender scrolling on reallifecomics.com with Renderer thread swamped in draw_alpha_batch_container		P3
defect	1732594	Browser freezes. 2.0s BHR detected hang		P3
defect	1457806	https://output.jsbin.com/surane/quiet is not smooth		P4
defect	1457683	servo moire demo is much slower in Firefox + WebRender than in Chrome		P5
defect	1639889	Scrolling hackmd.io is much worse in Firefox than Chrome		--
defect	1648597	Pinch to zoom on https://shkspr.mobi/blog/2020/06/symbian-won/ is slow		--

13 Total; 13 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Picture Caching

Metabug: picture-cache-perf

See also: incremental-perf

Useful prefs:

• gfx.webrender.debug.profiler-ui: "#Rendered picture tiles, ,Picture cache slices,Picture tiles,Picture tiles mem"

Full Query

Type	ID	Summary	Assigned to	Priority
enhancement	1536360	[meta] Picture caching improvements		P2
defect	1689746	Slow scrolling on weather.com today page	Glenn Watson [:gw]	P3
defect	1519718	Slow Frames detected on singlesprout home page	Dzmitry Malyshau [:kvark]	P3
defect	1581571	High GPU consumption on page with no visible changes.		P3
defect	1595680	Slightly different values in display lists causing extra picture cache invalidations.		P3
defect	1595909	Image masks with different keys being added during scrolling		P3
defect	1620401	"Open source. Open minds." on mozilla.org invalidates the picture cache when scrolling upwards		P3
defect	1675030	Picture cache invalidates when tile device rect is unchanged	Andrew Osmond [:aosmond]	P3
enhancement	1591540	Special-case solid color OS compositor surfaces in order to save memory		--
enhancement	1647080	WebRender/WR: Scrolling hangs shortly on purecss-francine	Glenn Watson [:gw]	--
defect	1647903	Scrolling https://github.com/servo/pathfinder/pull/350/files is a bad time		--

11 Total; 11 Open (100%); 0 Resolved (0%); 0 Verified (0%);

DisplayList building

Metabug: wr-displaylist-perf

Useful prefs:

• gfx.webrender.debug.profiler-ui: "Transaction times"

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1416082	[meta] MotionMark perf		P3
defect	1480964	With WR, Scrolling on maze solver page is janky. Non-WR is smooth (WR scrolling is not async enough)		P3
defect	1501545	testcase from bug 1123075 performs poorly on WR, and takes several GB of RAM on higher count		P3
enhancement	1533135	Scrolling on bing images search results is sluggish		P3
defect	1605155	Opening a video in Picture-in-Picture still causes the originating tab to compute DisplayLists at the video frame rate while the tab is the foreground		P3
defect	1617372	[WebRender] Higher CPU and GPU usage on https://f1sport.auto.cz/clanek/ztracime-hodnoti-binotto-ktery-neni-tak-optimisticky-jako-vloni		P3
enhancement	1631752	Serialize/deserialize the webrender displaylist to/from shared memory		P3

7 Total; 7 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Blob image rasterization

Metabug: blob-perf

Blob image performance affect SVG and a few drawing primitives that aren't supported by WebRender.

A few common themes in blob image performance bugs:

• Rasterization performance on the CPU (rasterization itself, malloc contention)
• Overhead of replaying commands on multiple tiles.
• Bad layerization causing many rasterized tiles and a lot of overdraw.
• Rendering very large blobs failing to account for parts that aren't visible.
• SVG filters on the CPU.

See also:

• SVG improvements proposal

Useful prefs:

• gfx.webrender.blob.paint-flashing: true
• gfx.webrender.debug.profiler-ui: "#Blob rasterization,#Rasterized blob pixels,#Rasterized blob tiles,#Rasterized blobs"

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1617420	Massive lags on page load on some sites including mouse movement		P2
enhancement	1447839	Stop using PathBuilderSkia in PathBuilderRecording	Jeff Muizelaar [:jrmuizel]	P2
defect	1450375	blob-image: https://www.jpro.one/ runs poorly	Jeff Muizelaar [:jrmuizel]	P2
defect	1686590	[Bug] Very slow, choppy performance of SVG compared to Chrome on same device (example included)		P3
defect	1552405	The "info" panel on the perf-html.io page scrolls really bad with WR (Blur/Filter related?)		P3
defect	1621532	The above the fold animation is too slow on https://kaganhotel.com		P3
enhancement	1686654	Reenable active SVG images		P3
defect	1557069	https://crisal.io/aemet-visualizer takes a lot of time to render beceause of high blob recording times		P3
enhancement	1623515	iPad Pro site takes over 100ms of GPU time with Webrender		P3
defect	1566942	Very slow animations with SVG filters.		P3
defect	1623634	Huge mask rasterization and upload on https://www.apple.com/ipad-pro/		P3
task	1567291	Malloc contention on WrWorker threads is still too high		P3
defect	1624304	Scrolling SVG lags badly and gets worse with WR		P3
defect	1705866	Slow scrolling on bose.com		P3
defect	1568027	WebRender performs worse on Binding of Isaac CodePen demo (svg filters/blob)		P3
task	1628105	Rasterize blobs in bigger buffers		P3
defect	1578964	Terrible animation performance (svg filters)		P3
defect	1637580	Very poor javascript + SVG animation performance		P3
defect	1719779	Slow blob recording in codepen demo (and bad gpu time)		P3
enhancement	1389712	switching to a Google Slides tab is slow (long repaint)		P3
defect	1579977	Poor scrolling performance on Apple Music Beta	Nicolas Silva [:nical]	P3
defect	1580864	Janky scrolling with interactive map		P3
enhancement	1583545	Add linear gradient clips in webrender	Nicolas Silva [:nical]	P3
enhancement	1661037	Render more types of SVG content with WebRender display items		P3
enhancement	1583879	Detect and skip empty blob tiles	Nicolas Silva [:nical]	P3
enhancement	1585781	SVG: Container item bounds changes cause invalidations		P3
enhancement	1661044	Avoid breaking blob groups in some cases		P3
enhancement	1458302	Use nsDisplayItem::IsReused as a preliminary check to figure out if nsDisplayTransform's transform has changed		P3
enhancement	1587827	Don't build gecko display items for SVG elements with webrender.		P3
defect	1662297	Zillow using massive amounts of memory		P3
defect	1477371	https://creativecluster.lu/ animation at very bottom of page is slow because of large blob	Jeff Muizelaar [:jrmuizel]	P3
defect	1594768	Too many blob layers on https://www.goodfour.us/		P3
defect	1493466	Circle animation on radio website is janky (too much texture upload because SVG blob clip is ignored)	Jeff Muizelaar [:jrmuizel]	P3
enhancement	1595799	Use webrender display items instead of blobs when possible		P3
defect	1514047	Too much blob layerization when clicking a circle on https://immersion.media.mit.edu/demo		P3
defect	1607890	Slow paints in visbug		P3
enhancement	1673653	Support for rasterizing SVG images on WR worker threads	Andrew Osmond [:aosmond]	P3
defect	1519622	Bad performance on https://musicmap.info when zooming with webrender enabled (svg/blob)		P3
enhancement	1610409	Add support for luminance masking in PushLayer		P3
defect	1676113	High CPU and big memory leak on windows 10 WebRender (SVG/Blob/Scenebuilder)		P3
defect	1551733	Pretty bad performance on http://mind-map.glitch.me/		P3
enhancement	1450402	Consider caching paths across recordings		P4
defect	1688765	[SVG] SVG images on https://test.ig-klettern.org/ make scrolling choppy and slow		--
defect	1698189	Excessive memory usage trigger by padding		--
defect	1708971	Up to 160% CPU load due to SVG animations on https://feedly.com		--
defect	1637876	Animations are very laggy while scrolling on Kaipoche site (NSFW)		--
defect	1644514	Incredible bad rendering performance on digitalocean.com hero due to Webrender display list jank		--
defect	1663387	Poor scrolling performance on westfield.co.nz (very large blob copy)	Glenn Watson [:gw]	--
defect	1667241	Large SVG image drawing on fivethirtyeight forecast		--

49 Total; 49 Open (100%); 0 Resolved (0%); 0 Verified (0%);

SVG filters metabug: wr-svg-filters

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1568027	WebRender performs worse on Binding of Isaac CodePen demo (svg filters/blob)		P3
task	1573657	Support SVG filter primitive subregions in WebRender		P3
task	1573994	Update Gecko to use new SVG filter primitives	Brad Werth [:bradwerth]	P3
defect	1578964	Terrible animation performance (svg filters)		P3
enhancement	1700721	Support combining sRGB conversion with filtering in brush_blend.glsl	Nicolas Silva [:nical]	P3
defect	1455427	SVG filters on HTML content is a bad time		P3
defect	1566942	Very slow animations with SVG filters.		P3
defect	1698365	https://www.digibank.co.il/ causes high CPU and power consumption		--
defect	1708971	Up to 160% CPU load due to SVG animations on https://feedly.com		--

9 Total; 9 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Glyph rasterization

These bugs affect CPU time and texture uploads.

Metabug: 1681339

Useful prefs:

• gfx.webrender.debug.glyph-flashing: true
• gfx.webrender.debug.profiler-ui: "#Rasterized glyphs,#Glyph resolve,#Texture cache update"

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1668431	Slow scrolling on Google Pixel 5 store page		P3
enhancement	1681346	Deduplicate system fonts in WebRender		P3
defect	1518995	Outstream.com page tilt effect is very laggy and jumpy with WebRender enabled		P3
defect	1672235	https://disneyanimation.com/data-sets/ renders slowly		--
defect	1674864	Slow scrolling on https://stirringabyss.com/		--
defect	1639889	Scrolling hackmd.io is much worse in Firefox than Chrome		--

6 Total; 6 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Scheduling

Metabug: frame-scheduling

Useful prefs:

• gfx.webrender.debug.profiler-ui: "#Content send,#API send"

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1603453	When the CPU is under load posting tasks to the renderer thread's eventloop can take a long time		P3
task	1612441	Investigate whether we can avoid blocking during swap buffers in the renderer		P3
enhancement	1612443	Do frame building and rendering on the same thread		P3
defect	1614734	Time spent stuck in RendererOGL::WaitForGPU()		P3
defect	1668339	Bad WR performance with low number of cores when the CPU is busy		P3
enhancement	1671490	Increase the priority of the gpu process		P3
defect	1686358	Hit testing interaction with the APZ lock can be expensive		P3
defect	1715317	Scrolling lag and stuttering on basic website - intel graphics		--
task	1735391	[meta] Reduce compositing latency by waiting for vsync in fewer cases		--

9 Total; 9 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Metabug: vsync

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1592530	GLXVsyncThread occupied high CPU (GLXtest process failed (exited with status 1): Unable to load libGL.so.1)		P2
enhancement	1563075	Implement FrameSource compositing abstraction		P3
defect	1586929	Fullscreen video vsync broken on g-sync capable monitors when enabled in nvidia control panel		P3
defect	1587040	VSync firing 255 times more frequently than normal during "display off" sleep on Windows		P3
defect	1592786	XWayland: Compositing gets capped at 30fps after extended uptime on Linux		P3
defect	1630490	Vsync cap on 144 hz Multi-monitor Setup & SW VSYNC		P3
defect	1647166	On Linux, rendering in multiple sessions splits refresh rate		P3
defect	1650276	VSync timestamp handling is confused, inconsistent, and non-optimal		P3
defect	1650499	Win7: Wrong Hz display detection		P3
defect	1657905	Firefox is laggy when using on external 75Hz 1080p monitor, on Pop OS, with and without webrenderer on, but window works perfectly fine when moved over to the laptop's display.		P3
defect	1400553	Firefox on primary monitor at 75hz makes firefox occasionally drop FPS. Vsync/DWM issue? (Redstone 3 build)		P3
defect	1562155	Linux hardware vsync guesses the rate, and interferes with requestIdleCallback		P3
enhancement	1681830	Stop using DwmFlush on Windows		--
defect	1687142	Vsync drift due to inaccurate mVsyncRate	Kacper Michajłow [:kasper93]	--
defect	1705695	[LINUX] Rendering at 60Hz despite the monitor refresh rate set to 144Hz when using MOZ_X11_EGL=1 (layout.frame_rate fixes it)		--

15 Total; 15 Open (100%); 0 Resolved (0%); 0 Verified (0%);

GPU time

Useful prefs:

• gfx.webrender.debug.profiler-ui: "Frame stats, ,#GPU,#Rendered picture tiles,|,GPU time queries"
• gfx.webrender.debug.gpu-time-queries: true

Caching

Metabug: wr-caching

Full Query

Type	ID	Summary	Assigned to	Priority
enhancement	1548396	Support picture caching on child pictures.		P2
defect	1463318	https://flow.org/ runs poorly with WebRender on low end GPUs		P2
defect	1528376	High GPU usage on https://pressprogress.ca/jason-kenneys-labour-reforms-are-arbitrary-and-ridiculous-workers-rights-advocates-say/		P3
defect	1550796	Bad GPU performance on https://ultralig.ht/ with WebRender		P3
defect	1552318	Scrolling is super laggy on https://templates.cartflows.com/ebook-landing/		P3
defect	1579977	Poor scrolling performance on Apple Music Beta	Nicolas Silva [:nical]	P3
defect	1519718	Slow Frames detected on singlesprout home page	Dzmitry Malyshau [:kvark]	P3

7 Total; 7 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Too many render passes

Metabug: wr-render-passes

Note, it's likely that most of the bugs below would be fixed by caching the render passes (bucket above).

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1664478	Blend modes and other effects on a single image force an extra intermediate target		P2
defect	1517926	Bad performance on nested CSS keyframe animation		P3
task	1549734	Reduce the resolution of some render tasks when going over GPU memory budget		P3
defect	1580864	Janky scrolling with interactive map		P3
enhancement	1597326	Avoid separate surfaces in WebRender if preserve-3d children don't intersect		P3
defect	1732594	Browser freezes. 2.0s BHR detected hang		P3

6 Total; 6 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Overdraw

Metabug: 1613404

Full Query

Type	ID	Summary	Assigned to	Priority
enhancement	1485534	Images that have alpha channels but are actually opaque go in the transparent pass	Patrick Walton (:pcwalton)	P2
defect	1504590	Slow 3d transform rendering on https://keithclark.co.uk/articles/pure-css-parallax-websites/demo3/ in debug mode		P3
enhancement	1558133	Reducing overdraw with huge semi-transparent images		P3
enhancement	1597324	Detect opaque split planes in WebRender		P3
defect	1733455	sw-wr: background image scrolling is very choppy on colorpeople.com		P3
defect	1457683	servo moire demo is much slower in Firefox + WebRender than in Chrome		P5
enhancement	1596634	When blur filter is applied on a large area, it delays the full rendering		--
defect	1674864	Slow scrolling on https://stirringabyss.com/		--

8 Total; 8 Open (100%); 0 Resolved (0%); 0 Verified (0%);

GPU times (others)

Metabug: wr-gpu-time

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1664478	Blend modes and other effects on a single image force an extra intermediate target		P2
defect	1614141	High gpu usage on https://pcsx4.com/faq/ on Mac		P3
enhancement	1623515	iPad Pro site takes over 100ms of GPU time with Webrender		P3
defect	1518995	Outstream.com page tilt effect is very laggy and jumpy with WebRender enabled		P3
defect	1528376	High GPU usage on https://pressprogress.ca/jason-kenneys-labour-reforms-are-arbitrary-and-ridiculous-workers-rights-advocates-say/		P3
defect	1550796	Bad GPU performance on https://ultralig.ht/ with WebRender		P3
defect	1728780	Bad GPU time on system76 website		P3
defect	1556166	Bad performance on https://www.gitbook.com/		P3
defect	1560671	https://www.cricketworldcup.com/ is slow		P3
enhancement	1651985	Animation causes webrender page to take more and more GPU time, resetting every ~10s		P3
defect	1561145	https://www.sidewalklabs.com is slow with WebRender		P3
defect	1652511	Scrolling on https://www.aspyredesign.com/ is extremely janky (with lots of time spent in painting)		P3
defect	1562369	Janky scrolling on https://www.bareminerals.com		P3
defect	1654231	Nvidia powerstates causing stuttering in web browser		P3
defect	1568877	Google calendar month transition is slow with WebRender		P3
defect	1659338	Janky scrolling on mobile in www.rrweb.io (bad GPU time)		P3
defect	1580264	Scrolling background causes 90+% GPU activity with webrender enabled		P3
enhancement	1664060	Tiled masks in WebRender		P3
enhancement	1583856	Segment very large border radii.		P3
defect	1668431	Slow scrolling on Google Pixel 5 store page		P3
enhancement	1606222	Network connection - High GPU load until the "connection timeout" message appear caused by throbber		P3
defect	1609055	Bad GPU times on hackmd.io		P3
defect	1673290	https://ics-creative.github.io/180914_conic_gradient/line_effect/ is slow due to large layer sizes and clips		P3
defect	1614105	Transitions between background images are janky on https://www.nrk.no/chasing-climate-change-1.14859595		P3
enhancement	1690401	brush_mix_blend shader could use premultiplied blend math instead of doing expensive un-premultiplies	Brad Werth [:bradwerth]	P3
enhancement	1694908	Turn picture composite modes into their own primitive kinds		--
enhancement	1695960	Better cache/reuse clip masks for rounded corners		--
task	1639336	Investigate high times in target_init GPU profiling bucket on low-end Intel GPUs	Bert Peers [:bpeers]	--
defect	1707845	Jittery 3D CSS		--
defect	1639889	Scrolling hackmd.io is much worse in Firefox than Chrome		--
enhancement	1709941	Avoid allocating clip targets with no tasks in WebRender		--
defect	1640435	https://blog.onepeloton.com/peloton-covid-19-initiatives/ scrolls poorly on Mac		--
enhancement	1647080	WebRender/WR: Scrolling hangs shortly on purecss-francine	Glenn Watson [:gw]	--
enhancement	1596634	When blur filter is applied on a large area, it delays the full rendering		--
defect	1672235	https://disneyanimation.com/data-sets/ renders slowly		--

35 Total; 35 Open (100%); 0 Resolved (0%); 0 Verified (0%);

GPU Memory usage

Metabug: wr-gpu-memory

Useful prefs:

- See all profile counters starting with "Texture cache" in addition to "Created targets".

Full Query

Type	ID	Summary	Assigned to	Priority
enhancement	1475518	Commit-space usage investigation		P3
defect	1614922	GPU memory usage is (very) high when gfx.webrender.compositor is enabled		P3
defect	1615051	Hangs caused by expensive animations on https://paulstamatiou.com/work/ can freeze Firefox		P3
defect	1701643	Webrender per-window memory overhead is high		P3
enhancement	1701986	Share and reuse Direct composition surfaces between multiple windows		P3
defect	1716317	A lot of GPU memory goes into the render target pool	Nicolas Silva [:nical]	P3
enhancement	1716525	Flush caches and pools from least recently shown windows when under memory pressure		P3
enhancement	1716579	Reduce the memory usage of windows that haven't been rendered for a long time	Nicolas Silva [:nical]	P3
defect	1715957	Very high gpu memory usage with many windows		--

9 Total; 9 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Android

Metabug: wr-android-perf

Full Query

Type	ID	Summary	Assigned to	Priority
enhancement	1536358	Prototype using PLS for clip task rendering on mobile devices with WR		P2
defect	1665518	leganerd.com unbereably laggy on Fenix	Andrew Osmond [:aosmond]	P2
defect	1498735	Too much GPU time in the sidebar animation on html5test.com on Android		P3
enhancement	1507669	Fix RGBA format handling in SurfaceTextureHost::PushResourceUpdates()		P3
enhancement	1533135	Scrolling on bing images search results is sluggish		P3
enhancement	1562818	Add support of AHardwareBuffer on Android	Sotaro Ikeda [:sotaro]	P3
defect	1609217	Scrolling on https://webassembly-summit.org/speakers/ feels sluggish with WebRender on Samsung Galaxy A7		P3
enhancement	1614694	Load non-startup shaders from disk in a background thread	Jamie Nicol [:jnicol]	P3
defect	1617979	Reduce Renderer initialization time on Android		P3
defect	1618968	First frame rendering takes longer in Fenix than Fennec due to WebRender		P3
defect	1629443	Stuttering scroll with WebRender on Pocket Trending page (LG G4, Adreno 418)		P3
defect	1732817	Scrolling on apple.com is much less smooth on fenix than in chrome with backdrop-filter		--

12 Total; 12 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Linux

Metabug: wr-linux-perf

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1583881	Stuttering while scrolling on Intel GPU on Linux		P3
defect	1601432	WebRender abnormal high CPU load with JavaScript off		P3
defect	1650731	Extremely high input latency with Mattermost		P3
defect	1676445	Enabling WebRender regresses several AWSY results		P3
defect	1682135	Low frame and late response for hamburger menu from Linux Firefox 85 with 125% fractional scaling (waiting on the window server)		P3
defect	1676818	webrender is slower on web.basemark.com		P4
enhancement	1640710	[meta] wr-non-os-compositor		P5
defect	1530951	3.58 - 3.99% sessionrestore / sessionrestore_no_auto_restore / ts_paint / ts_paint_webext (linux64-pgo-qr) regression on push 44192297e3ae55473fbe669a681f937191a54b81 (Tue Feb 26 2019)		P5
defect	1640100	8% Heap Unclassified (linux1804-64-shippable-qr) regression on push 0caead34be39e30750098ceaf5738dd0d1850273 (Fri May 15 2020)		--
defect	1659143	OpenGL compositing and webrender lower performance in Firefox on Linux on Intel HD 5500		--
enhancement	788319	[meta] Use EGL instead of GLX on X11		--

11 Total; 11 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Software WebRender (SWGL)

Metabug: sw-wr-perf

Full Query

Type	ID	Summary	Assigned to	Priority
enhancement	1669842	Make sure our present path on Windows is as fast as possible		P3
defect	1678800	Janking while doing touchpad scroll on kobol.io (sw-wr)		P3
defect	1713648	Bad performance with SWGL on https://termsandconditions.game/		P3
enhancement	1695273	[NSFW] Slowness remaining on scrolling nsfw reddit after bug 1694017 is resolved		P3
defect	1730270	FF 92 on C2D and Intel 965, poor webrender performance when playing video, no problem with Direct3D. FF displays windows incorrectly, changes the dimensions and position/jumping bars		P3
enhancement	1695564	Add partial rects handling to RenderCompositorD3D11SWGL		P3
defect	1733405	No-op composites with SWGL do too much work		P3
defect	1733455	sw-wr: background image scrolling is very choppy on colorpeople.com		P3
enhancement	1699765	Implement async uploads for Android+ES2 in RenderCompositorOGLSWGL		P3
defect	1705006	Scrolling on google images is janky on Mali-400(sw-wr)		P3
task	1621383	Software WebRender benchmarking		P3
enhancement	1647951	Investigate shared SWGL contexts or some form of inter-window SWGL resource sharing		P3
defect	1705986	(sw-wr) A little stuttery scrolling on https://www.timecube.com/		P3
enhancement	1692583	Make SWGL use a polynomial approximation for atan2() for conic gradients		P4
enhancement	1696101	Add partial rects handling to RenderCompositorOGLSWGL		P4
defect	1709737	rally.mozilla.org parallax animation is very laggy with SW-WR		--
defect	1710489	Scrolling on facebook slow after some time with webrender-software		--
defect	1711685	Scrolling is janky on news.ycombinator.com with sw-wr on a Mali400 device		--
defect	1680821	Software webrender is slow with large SVGs		--
defect	1711694	Poor performance while scrolling w/swiggle (Pixel 3)		--
defect	1681747	sw-wr performance bad when viewing pdfs on macOS	Matt Woodrow (:mattwoodrow)	--
defect	1711998	texture conversion during glTexSubImage with sw-wr on mali-400		--
defect	1683230	Bad border performance on amazon ad with SW-WR	Brad Werth [:bradwerth]	--
defect	1727993	Each window currently has its own SwComposite thread - please share one thread across all windows		--
enhancement	1697500	[meta] sw-wr android		--
defect	1700597	Hovering or scrolling over past editions on https://www.miragefestival.com WebRender is laggy with Webrender software enabled		--
defect	1700921	Flipping pages on Flippingbook.com is jerky with Webrender Software enabled		--
enhancement	1705925	(sw-wr) Stuttery scrolling on https://www.foxitsoftware.com/pdf-reader/	Glenn Watson [:gw]	--

28 Total; 28 Open (100%); 0 Resolved (0%); 0 Verified (0%);

See also:

• sw-wr-perf-opacity
• sw-wr-perf-nearest
• sw-wr-perf-alpha
• sw-wr-perf-mix-blend
• sw-wr-perf-clip-rect
• sw-wr-perf-clip-image

Canvas 2D

Metabug: canvas-perf

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1190398	BLCK4777 1kb js site is very janky with my triangles on screen		P3
defect	1656959	Significantly higher GPU use in Firefox on bilibili.com when compared to Chromium browsers		P3
defect	1662203	Canvas on android causes stuttering (https://store.google.com/ca/product/pixel_4a)		P3
defect	1673168	Poor drawImage() video performance compared to other browsers		P3
defect	1560450	[meta] Some apps are slower with software-only canvas2d		--
defect	1671968	Playback continues even after closing a tab		--
defect	1672452	https://map.mta.info is slow on macOS		--
defect	1689691	Bad performance on Vertex (nytimes.com game)		--

8 Total; 8 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Tools

Metabug: wr-perf-tools

Full Query

Type	ID	Summary	Assigned to	Priority
task	1645021	Reduce the cost of displaying HUD profiling tools in WebRender		P3
task	1728620	Add some telemetry for slow frame categories	Nicolas Silva [:nical]	P3
defect	1737001	Crash in RenderCompositorEGL::EndFrame when using renderdoc on Linux		P3
task	1583884	Show the number of blob tiles in existence in webrender's builtin profiler HUD		P3
enhancement	1641101	Add support for profiling how often the same glyph has been evicted and re-rasterized		P3

5 Total; 5 Open (100%); 0 Resolved (0%); 0 Verified (0%);

General WebRender perf metabug

Metabug: wr-perf

During graphics triage, WebRender performance bugs are added as dependency to the wr-perf meta-bug. The next step is to replace the wr-perf dependency with one of the more specific meta-bugs above.

Full Query

Type	ID	Summary	Assigned to	Priority
defect	1487864	Improve frame scheduling in WebRender - Strange couplets of animation frames on expensive main-thread-driven animation		P2
task	1613373	[meta] WebRender SVG filters		P3
enhancement	1631949	Investigate merging shader cache files	Doug Thayer [:dthayer] (he/him)	P3
enhancement	1682206	Add a capability to disable video rendering to Main window during PIP		P3
enhancement	1525420	Slow performance on https://keithclark.co.uk/labs/css-fps/nojs/	Dzmitry Malyshau [:kvark]	P3
task	1613387	[meta] WebRender DisplayList building performance		P3
task	1638122	[meta] Webrender android performance		P3
defect	1683290	PiP doubles CPU and GPU load		P3
enhancement	1526020	Slightly worse performance on sessionrestore talos test on windows-qr		P3
task	1613389	[meta] WebRender caching		P3
defect	1683975	Opening a new tab on Big Sur is delayed by 100ms due to system font initialization	Markus Stange [:mstange]	P3
enhancement	1533135	Scrolling on bing images search results is sluggish		P3
task	1613396	[meta] WebRender: Too many render passes		P3
enhancement	1545578	Investigate loading early libraries with RTLD_DEEPBIND for WebRender talos wins		P3
task	1613404	[meta] WebRender GPU time - overdraw		P3
defect	1720263	Increased suttering in Firefox 90 when using multiple monitors with WEBRENDER_DCOMP_PRESENT disabled (=Nvidia default)		P3
task	1549734	Reduce the resolution of some render tasks when going over GPU memory budget		P3
task	1613407	[meta] WebRender performance - texture/buffer uploads		P3
task	1567511	Very noisy GPU times		P3
defect	1619093	Scrolling smoothness is worse on WebRender.	Dzmitry Malyshau [:kvark]	P3
task	1583884	Show the number of blob tiles in existence in webrender's builtin profiler HUD		P3
task	1620683	Investigate how long the SyncObjectD3D11Host::Synchronize() call in BeginFrame() takes		P3
enhancement	1587827	Don't build gecko display items for SVG elements with webrender.		P3
task	1623643	[meta] Picture caching performance		P3
defect	1648843	scrolling performance regression for specific site on nightly + webrender		P3
task	1692031	Allow usage of KHR_blend_equation_advanced on hardware WR		P3
enhancement	1589307	Allow rendering some picture tiles directly into the framebuffer		P3
task	1624261	[meta] Reduce WebRender's GPU memory usage		P3
task	1659723	[meta] WebRender GPU time		P3
enhancement	1692071	Async-er scrolling for WebRender		P3
task	1728787	[meta] Low end GPU performance		P3
task	1594474	[meta] WebRender batching		P3
enhancement	1624493	Remove brush_opacity shader and replace it with brush_image		P3
task	1659734	[meta] WebRender Driver/API overhead on the renderer thread		P3
defect	1692342	Masked video on https://www.apple.com/ca/iphone-se/ is wrong and renders slow		P3
task	1594490	[meta] Improve WebRender's performance tools		P3
defect	1625013	noclip.website doesn't run well when using track pad		P3
task	1660479	[meta] WebRender scene building performance		P3
task	1596042	[meta] Frame building performance		P3
defect	1625433	Text and background elements animations are stuttering on fantasy.bnf.fr		P3
defect	1501545	testcase from bug 1123075 performs poorly on WR, and takes several GB of RAM on higher count		P3
task	1628677	Investigate SSBOs for the GPU cache		P3
enhancement	1673653	Support for rasterizing SVG images on WR worker threads	Andrew Osmond [:aosmond]	P3
defect	1605155	Opening a video in Picture-in-Picture still causes the originating tab to compute DisplayLists at the video frame rate while the tab is the foreground		P3
enhancement	1628682	Map large buffers that the render backend can fill directly		P3
enhancement	1607452	[meta] WR Perf P1s		P3
enhancement	1631752	Serialize/deserialize the webrender displaylist to/from shared memory		P3
task	1698701	Consider disabling subpixel AA by default on high resolution devices		P3
enhancement	1522262	https://www.quantifiedplanet.org/ is slower with Firefox than Chrome		P3
task	1728788	[meta] wr-perf graveyard		P4
defect	1509966	[meta] Slow frames on a variety of pages		P4
task	1640712	non-os-compositor: Damage rects currently get joined to the bounding rect		P5
enhancement	1370998	[meta] Tracking bug for WebRender memory issues		P5
enhancement	1599611	enable putting hit test info on container display items (from bug 1503046) for webrender		P5
enhancement	1508188	[meta] perf bugs included in the CONTENT_FULL_PAINT_TIME metric		P5
defect	1708408	Up to 50% CPU load for animated (job is running) SVG on Github Actions page		--
defect	1709638	Overscrolling on reddit causes fullscreen repaints		--
defect	1639892	WebRender doesn't work great on https://en.wikipedia.org/wiki/Grey%27s_Anatomy_(season_16) on Mac		--
defect	1710472	WebRender Mac: large GPU power use when showing PDF inline		--
defect	1640205	Scrolling is slow on https://garry.tv/unity-2020 on macOS		--
defect	1686109	RenderCompositorNative::MaybeGrabScreenshot should check ProfilerScreenshots::IsEnabled() before calling mNativeLayerRoot->CreateSnapshotter()		--
enhancement	1710778	Testcase is much more slower with animated text and faster if animated text is removed	Glenn Watson [:gw]	--
defect	1689225	Low FPS Scrolling on Touchpad (Windows 4k)		--
defect	1642276	Slow frames, CPU heating up on Google Pixelbook Go product page on Google Store		--
task	1689392	[Meta] investigate performance issues on Reddit.		--
enhancement	1720979	Slow animation (and lots of CPU use) on a codepen demo		--
defect	1647484	https://www.apple.com/macos/big-sur-preview/ has bad performance with WebRender		--
defect	1690673	We can get into a state where the compositor keeps compositing even though there's nothing to do		--
defect	1721702	twitch uses more GPU in Firefox than Chrome		--
enhancement	1647947	Expose dirty regions before wr_renderer_render so that RenderCompositor::BeginFrame can utilize them		--
task	1691404	[meta] incremental perf		--
defect	1722764	Juddering on touchpad scroll on Facebook Marketplace		--
defect	1725420	Slow loading of page elements on wizard-shoji.webflow.io caused by large svg image		--
defect	1692585	pause on initial load with WebRender on Intel HD 4600		--
defect	1730823	FF 92 High GPU usage randomly		--
enhancement	1667917	Allow binding WebGL IOSurface directly to CoreAnimation compositor layers		--
defect	1692828	Scrolling lags due to long composites on mac		--
defect	1732196	Pinch to zoom lag in fenix on gsmarena's desktop site		--
task	1600219	Investigate to remove WaitForGPU()		--
defect	1693130	Stuttering while scrolling on Nvidia 144Hz monitor		--
defect	1674837	scrolling https://utmagazine.ru/finansoviy-slovar-treidera is not smooth		--
defect	1698673	Janking while doing touchpad scroll on yahoo.com		--
defect	1677364	After OOM crash nn a contrived testcase, the GPU process doesnt release 4.1GB memory unless force terminated from about:support	Brad Werth [:bradwerth]	--

83 Total; 83 Open (100%); 0 Resolved (0%); 0 Verified (0%);

Other meta-bugs:

- wr-low-end-perf
- wr-perf-graveyard