Status

()

defect
P2
normal
Last year
7 months ago

People

(Reporter: jrmuizel, Unassigned)

Tracking

(Blocks 2 bugs)

unspecified
Points:
---
Dependency tree / graph

Firefox Tracking Flags

(firefox60 wontfix, firefox61 wontfix, firefox62 fix-optional)

Details

Attachments

(1 attachment)

Posted file flow.html
This runs at 16fps on my MBP. The title has 500 text shadows :(

I've attached a somewhat reduced copy of the page.
Flags: needinfo?(gwatson)
Batch updating status flags based on WR schedule - please adjust if needed.
Priority: -- → P2
You can assign this to me if you like - it'll need some profiling to see (a) if the text shadows are not being cached (and if not, why not) and (b) what the exact cause of the GPU time slowness is.
Flags: needinfo?(gwatson)
Yup, as Jeff mentioned above, this is entirely due to the "interesting" text-shadow effect on the header bar. If I disable that, or scroll past it, the rest of the page is easily running at 60fps. The CSS rule for the text-shadow effect is:

    text-shadow: 1px 1px #2d343a, 2px 2px #2d343a, 3px 3px #2d343a, 4px 4px #2d343a, 5px 5px #2d343a, 6px 6px #2d343a, 7px 7px #2d343a, 8px 8px #2d343a, 9px 9px #2d343a, 10px 10px #2d343a, 11px 11px #2d343a, 12px 12px #2d343a, 13px 13px #2d343a, 14px 14px #2d343a, 15px 15px #2d343a, 16px 16px #2d343a, 17px 17px #2d343a, 18px 18px #2d343a, 19px 19px #2d343a, 20px 20px #2d343a, 21px 21px #2d343a, 22px 22px #2d343a, 23px 23px #2d343a, 24px 24px #2d343a, 25px 25px #2d343a, 26px 26px #2d343a, 27px 27px #2d343a, 28px 28px #2d343a, 29px 29px #2d343a, 30px 30px #2d343a, 31px 31px #2d343a, 32px 32px #2d343a, 33px 33px #2d343a, 34px 34px #2d343a, 35px 35px #2d343a, 36px 36px #2d343a, 37px 37px #2d343a, 38px 38px #2d343a, 39px 39px #2d343a, 40px 40px #2d343a, 41px 41px #2d343a, 42px 42px #2d343a, 43px 43px #2d343a, 44px 44px #2d343a, 45px 45px #2d343a, 46px 46px #2d343a, 47px 47px #2d343a, 48px 48px #2d343a, 49px 49px #2d343a, 50px 50px #2d343a, 51px 51px #2d343a, 52px 52px #2d343a, 53px 53px #2d343a, 54px 54px #2d343a, 55px 55px #2d343a, 56px 56px #2d343a, 57px 57px #2d343a, 58px 58px #2d343a, 59px 59px #2d343a, 60px 60px #2d343a, 61px 61px #2d343a, 62px 62px #2d343a, 63px 63px #2d343a, 64px 64px #2d343a, 65px 65px #2d343a, 66px 66px #2d343a, 67px 67px #2d343a, 68px 68px #2d343a, 69px 69px #2d343a, 70px 70px #2d343a, 71px 71px #2d343a, 72px 72px #2d343a, 73px 73px #2d343a, 74px 74px #2d343a, 75px 75px #2d343a, 76px 76px #2d343a, 77px 77px #2d343a, 78px 78px #2d343a, 79px 79px #2d343a, 80px 80px #2d343a, 81px 81px #2d343a, 82px 82px #2d343a, 83px 83px #2d343a, 84px 84px #2d343a, 85px 85px #2d343a, 86px 86px #2d343a, 87px 87px #2d343a, 88px 88px #2d343a, 89px 89px #2d343a, 90px 90px #2d343a, 91px 91px #2d343a, 92px 92px #2d343a, 93px 93px #2d343a, 94px 94px #2d343a, 95px 95px #2d343a, 96px 96px #2d343a, 97px 97px #2d343a, 98px 98px #2d343a, 99px 99px #2d343a, 100px 100px #2d343a, 101px 101px #2d343a, 102px 102px #2d343a, 103px 103px #2d343a, 104px 104px #2d343a, 105px 105px #2d343a, 106px 106px #2d343a, 107px 107px #2d343a, 108px 108px #2d343a, 109px 109px #2d343a, 110px 110px #2d343a, 111px 111px #2d343a, 112px 112px #2d343a, 113px 113px #2d343a, 114px 114px #2d343a, 115px 115px #2d343a, 116px 116px #2d343a, 117px 117px #2d343a, 118px 118px #2d343a, 119px 119px #2d343a, 120px 120px #2d343a, 121px 121px #2d343a, 122px 122px #2d343a, 123px 123px #2d343a, 124px 124px #2d343a, 125px 125px #2d343a, 126px 126px #2d343a, 127px 127px #2d343a, 128px 128px #2d343a, 129px 129px #2d343a, 130px 130px #2d343a, 131px 131px #2d343a, 132px 132px #2d343a, 133px 133px #2d343a, 134px 134px #2d343a, 135px 135px #2d343a, 136px 136px #2d343a, 137px 137px #2d343a, 138px 138px #2d343a, 139px 139px #2d343a, 140px 140px #2d343a, 141px 141px #2d343a, 142px 142px #2d343a, 143px 143px #2d343a, 144px 144px #2d343a, 145px 145px #2d343a, 146px 146px #2d343a, 147px 147px #2d343a, 148px 148px #2d343a, 149px 149px #2d343a, 150px 150px #2d343a, 151px 151px #2d343a, 152px 152px #2d343a, 153px 153px #2d343a, 154px 154px #2d343a, 155px 155px #2d343a, 156px 156px #2d343a, 157px 157px #2d343a, 158px 158px #2d343a, 159px 159px #2d343a, 160px 160px #2d343a, 161px 161px #2d343a, 162px 162px #2d343a, 163px 163px #2d343a, 164px 164px #2d343a, 165px 165px #2d343a, 166px 166px #2d343a, 167px 167px #2d343a, 168px 168px #2d343a, 169px 169px #2d343a, 170px 170px #2d343a, 171px 171px #2d343a, 172px 172px #2d343a, 173px 173px #2d343a, 174px 174px #2d343a, 175px 175px #2d343a, 176px 176px #2d343a, 177px 177px #2d343a, 178px 178px #2d343a, 179px 179px #2d343a, 180px 180px #2d343a, 181px 181px #2d343a, 182px 182px #2d343a, 183px 183px #2d343a, 184px 184px #2d343a, 185px 185px #2d343a, 186px 186px #2d343a, 187px 187px #2d343a, 188px 188px #2d343a, 189px 189px #2d343a, 190px 190px #2d343a, 191px 191px #2d343a, 192px 192px #2d343a, 193px 193px #2d343a, 194px 194px #2d343a, 195px 195px #2d343a, 196px 196px #2d343a, 197px 197px #2d343a, 198px 198px #2d343a, 199px 199px #2d343a, 200px 200px #2d343a, 201px 201px #2d343a, 202px 202px #2d343a, 203px 203px #2d343a, 204px 204px #2d343a, 205px 205px #2d343a, 206px 206px #2d343a, 207px 207px #2d343a, 208px 208px #2d343a, 209px 209px #2d343a, 210px 210px #2d343a, 211px 211px #2d343a, 212px 212px #2d343a, 213px 213px #2d343a, 214px 214px #2d343a, 215px 215px #2d343a, 216px 216px #2d343a, 217px 217px #2d343a, 218px 218px #2d343a, 219px 219px #2d343a, 220px 220px #2d343a, 221px 221px #2d343a, 222px 222px #2d343a, 223px 223px #2d343a, 224px 224px #2d343a, 225px 225px #2d343a, 226px 226px #2d343a, 227px 227px #2d343a, 228px 228px #2d343a, 229px 229px #2d343a, 230px 230px #2d343a, 231px 231px #2d343a, 232px 232px #2d343a, 233px 233px #2d343a, 234px 234px #2d343a, 235px 235px #2d343a, 236px 236px #2d343a, 237px 237px #2d343a, 238px 238px #2d343a, 239px 239px #2d343a, 240px 240px #2d343a, 241px 241px #2d343a, 242px 242px #2d343a, 243px 243px #2d343a, 244px 244px #2d343a, 245px 245px #2d343a, 246px 246px #2d343a, 247px 247px #2d343a, 248px 248px #2d343a, 249px 249px #2d343a, 250px 250px #2d343a, 251px 251px #2d343a, 252px 252px #2d343a, 253px 253px #2d343a, 254px 254px #2d343a, 255px 255px #2d343a, 256px 256px #2d343a, 257px 257px #2d343a, 258px 258px #2d343a, 259px 259px #2d343a, 260px 260px #2d343a, 261px 261px #2d343a, 262px 262px #2d343a, 263px 263px #2d343a, 264px 264px #2d343a, 265px 265px #2d343a, 266px 266px #2d343a, 267px 267px #2d343a, 268px 268px #2d343a, 269px 269px #2d343a, 270px 270px #2d343a, 271px 271px #2d343a, 272px 272px #2d343a, 273px 273px #2d343a, 274px 274px #2d343a, 275px 275px #2d343a, 276px 276px #2d343a, 277px 277px #2d343a, 278px 278px #2d343a, 279px 279px #2d343a, 280px 280px #2d343a, 281px 281px #2d343a, 282px 282px #2d343a, 283px 283px #2d343a, 284px 284px #2d343a, 285px 285px #2d343a, 286px 286px #2d343a, 287px 287px #2d343a, 288px 288px #2d343a, 289px 289px #2d343a, 290px 290px #2d343a, 291px 291px #2d343a, 292px 292px #2d343a, 293px 293px #2d343a, 294px 294px #2d343a, 295px 295px #2d343a, 296px 296px #2d343a, 297px 297px #2d343a, 298px 298px #2d343a, 299px 299px #2d343a, 300px 300px #2d343a, 301px 301px #2d343a, 302px 302px #2d343a, 303px 303px #2d343a, 304px 304px #2d343a, 305px 305px #2d343a, 306px 306px #2d343a, 307px 307px #2d343a, 308px 308px #2d343a, 309px 309px #2d343a, 310px 310px #2d343a, 311px 311px #2d343a, 312px 312px #2d343a, 313px 313px #2d343a, 314px 314px #2d343a, 315px 315px #2d343a, 316px 316px #2d343a, 317px 317px #2d343a, 318px 318px #2d343a, 319px 319px #2d343a, 320px 320px #2d343a, 321px 321px #2d343a, 322px 322px #2d343a, 323px 323px #2d343a, 324px 324px #2d343a, 325px 325px #2d343a, 326px 326px #2d343a, 327px 327px #2d343a, 328px 328px #2d343a, 329px 329px #2d343a, 330px 330px #2d343a, 331px 331px #2d343a, 332px 332px #2d343a, 333px 333px #2d343a, 334px 334px #2d343a, 335px 335px #2d343a, 336px 336px #2d343a, 337px 337px #2d343a, 338px 338px #2d343a, 339px 339px #2d343a, 340px 340px #2d343a, 341px 341px #2d343a, 342px 342px #2d343a, 343px 343px #2d343a, 344px 344px #2d343a, 345px 345px #2d343a, 346px 346px #2d343a, 347px 347px #2d343a, 348px 348px #2d343a, 349px 349px #2d343a, 350px 350px #2d343a, 351px 351px #2d343a, 352px 352px #2d343a, 353px 353px #2d343a, 354px 354px #2d343a, 355px 355px #2d343a, 356px 356px #2d343a, 357px 357px #2d343a, 358px 358px #2d343a, 359px 359px #2d343a, 360px 360px #2d343a, 361px 361px #2d343a, 362px 362px #2d343a, 363px 363px #2d343a, 364px 364px #2d343a, 365px 365px #2d343a, 366px 366px #2d343a, 367px 367px #2d343a, 368px 368px #2d343a, 369px 369px #2d343a, 370px 370px #2d343a, 371px 371px #2d343a, 372px 372px #2d343a, 373px 373px #2d343a, 374px 374px #2d343a, 375px 375px #2d343a, 376px 376px #2d343a, 377px 377px #2d343a, 378px 378px #2d343a, 379px 379px #2d343a, 380px 380px #2d343a, 381px 381px #2d343a, 382px 382px #2d343a, 383px 383px #2d343a, 384px 384px #2d343a, 385px 385px #2d343a, 386px 386px #2d343a, 387px 387px #2d343a, 388px 388px #2d343a, 389px 389px #2d343a, 390px 390px #2d343a, 391px 391px #2d343a, 392px 392px #2d343a, 393px 393px #2d343a, 394px 394px #2d343a, 395px 395px #2d343a, 396px 396px #2d343a, 397px 397px #2d343a, 398px 398px #2d343a, 399px 399px #2d343a, 400px 400px #2d343a, 401px 401px #2d343a, 402px 402px #2d343a, 403px 403px #2d343a, 404px 404px #2d343a, 405px 405px #2d343a, 406px 406px #2d343a, 407px 407px #2d343a, 408px 408px #2d343a, 409px 409px #2d343a, 410px 410px #2d343a, 411px 411px #2d343a, 412px 412px #2d343a, 413px 413px #2d343a, 414px 414px #2d343a, 415px 415px #2d343a, 416px 416px #2d343a, 417px 417px #2d343a, 418px 418px #2d343a, 419px 419px #2d343a, 420px 420px #2d343a, 421px 421px #2d343a, 422px 422px #2d343a, 423px 423px #2d343a, 424px 424px #2d343a, 425px 425px #2d343a, 426px 426px #2d343a, 427px 427px #2d343a, 428px 428px #2d343a, 429px 429px #2d343a, 430px 430px #2d343a, 431px 431px #2d343a, 432px 432px #2d343a, 433px 433px #2d343a, 434px 434px #2d343a, 435px 435px #2d343a, 436px 436px #2d343a, 437px 437px #2d343a, 438px 438px #2d343a, 439px 439px #2d343a, 440px 440px #2d343a, 441px 441px #2d343a, 442px 442px #2d343a, 443px 443px #2d343a, 444px 444px #2d343a, 445px 445px #2d343a, 446px 446px #2d343a, 447px 447px #2d343a, 448px 448px #2d343a, 449px 449px #2d343a, 450px 450px #2d343a, 451px 451px #2d343a, 452px 452px #2d343a, 453px 453px #2d343a, 454px 454px #2d343a, 455px 455px #2d343a, 456px 456px #2d343a, 457px 457px #2d343a, 458px 458px #2d343a, 459px 459px #2d343a, 460px 460px #2d343a, 461px 461px #2d343a, 462px 462px #2d343a, 463px 463px #2d343a, 464px 464px #2d343a, 465px 465px #2d343a, 466px 466px #2d343a, 467px 467px #2d343a, 468px 468px #2d343a, 469px 469px #2d343a, 470px 470px #2d343a, 471px 471px #2d343a, 472px 472px #2d343a, 473px 473px #2d343a, 474px 474px #2d343a, 475px 475px #2d343a, 476px 476px #2d343a, 477px 477px #2d343a, 478px 478px #2d343a, 479px 479px #2d343a, 480px 480px #2d343a, 481px 481px #2d343a, 482px 482px #2d343a, 483px 483px #2d343a, 484px 484px #2d343a, 485px 485px #2d343a, 486px 486px #2d343a, 487px 487px #2d343a, 488px 488px #2d343a, 489px 489px #2d343a, 490px 490px #2d343a, 491px 491px #2d343a, 492px 492px #2d343a, 493px 493px #2d343a, 494px 494px #2d343a, 495px 495px #2d343a, 496px 496px #2d343a, 497px 497px #2d343a, 498px 498px #2d343a, 499px 499px #2d343a, 500px 500px #2d343a;

This gives a kind of very long, angled text extrusion effect.

We have a few bugs with this kind of performance issue - that is, an individual effect which is not slow, but the effect is used dozens or hundreds of times, which adds up quickly.

The best way to solve this will be to cache such stacking contexts to a surface that is pre-blended. The support for this already exists in WR - the tricky bit is coming up with the right heuristic to know when it makes sense to cache a surface like this.

I'll do some experiments on this next week - I think a reasonable heuristic can be made by approximating the number of overdraw pixels with opacity / blend in an element, which is quick to calculate and is typically directly proportional to measured GPU time.
I think this is a duplicate of 1422567, but that one also uses blurs.
See Also: → 1422567
Blocks: wr-perf
This is likely addressed by the picture caching work that Glenn is doing.
Depends on: picture-caching

With picture caching enabled + multiple dirty rect support, this generally runs at a smooth 60 fps for me on an Intel HD4600.

If I scroll very quickly, I can see a little bit of jank as the 500 text runs come back into view. To fix this, we would need to either (a) retain cached tiles for longer, at the cost of extra GPU memory, or (b) Make optimizations to the underlying speed of drawing this many overlapping text runs (I have some ideas here, but they're not quick fixes).

Given that, I think this can probably be closed and/or no longer a blocker. Does that seem reasonable Jeff?

Flags: needinfo?(jmuizelaar)

(Of course, once they do come back into view they are quickly cached and the jank disappears).

Yep. This is good enough to ship.

Blocks: stage-wr-next
No longer blocks: stage-wr-trains
Flags: needinfo?(jmuizelaar)
Assignee: gwatson → nobody
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