iOS. Investigate 60 FPS limit during scrolling on 120 Hz devices in real world applications

[igordmn]

In some applications there is still no full 120 FPS during scrolling

Use this FPS counter:

@Composable
fun FPSCounter() {
    LaunchedEffect(Unit) {
        val fpsCounter = org.jetbrains.skiko.FPSCounter(logOnTick = true)
        while (true) {
            withFrameNanos {
                fpsCounter.tick()
            }
        }
    }
}

And scroll some lists in these applications:

https://github.com/chrisbanes/tivi

1.5.0-rc01

[1655239601] FPS 46 (4-139)
[1655241601] FPS 60 (59-61)
[1655243618] FPS 61 (40-140)
[1655245635] FPS 61 (48-318)
[1655247682] FPS 53 (6-143)
[1655249693] FPS 44 (6-125)
[1655251721] FPS 40 (10-120)
[1655253735] FPS 39 (10-121)
[1655255735] FPS 55 (30-143)
[1655257749] FPS 71 (40-138)
[1655259752] FPS 67 (40-252)
[1655261752] FPS 80 (39-153)
[1655263761] FPS 67 (34-143)
[1655265761] FPS 73 (40-264)
[1655267778] FPS 38 (2-142)
[1655269786] FPS 49 (4-141)
[1655271795] FPS 57 (10-150)
[1655273803] FPS 70 (13-201)
[1655275803] FPS 77 (35-135)
[1655277803] FPS 86 (20-290)
[1655279803] FPS 82 (40-251)
[1655281804] FPS 68 (30-158)
[1655283820] FPS 60 (58-61)
[1655285821] FPS 60 (59-61)
[1655287821] FPS 53 (4-137)
[1655289838] FPS 59 (5-378)
[1655291846] FPS 64 (13-141)
[1655293846] FPS 68 (40-139)
[1655295855] FPS 86 (40-146)

1.5.0-rc04

[1654238271] FPS 57 (9-119)
[1654240271] FPS 62 (37-171)
[1654242271] FPS 60 (59-61)
[1654244280] FPS 56 (8-160)
[1654246288] FPS 63 (46-357)
[1654248296] FPS 73 (56-139)
[1654250297] FPS 60 (58-62)
[1654252305] FPS 60 (40-64)
[1654254306] FPS 60 (59-61)
[1654256322] FPS 60 (58-62)
[1654258323] FPS 60 (59-61)
[1654260331] FPS 60 (39-65)
[1654262331] FPS 60 (59-61)
[1654264348] FPS 60 (59-61)
[1654266356] FPS 59 (8-155)
[1654268389] FPS 32 (4-149)
[1654270406] FPS 52 (7-130)
[1654272406] FPS 26 (6-61)
[1654274407] FPS 49 (8-61)
[1654276407] FPS 60 (59-61)

https://github.com/touchlab/DroidconKotlin
1.5.0-dev1080

[2140369259] FPS 101 (12-623)
[2140371268] FPS 100 (60-397)
[2140373270] FPS 100 (61-394)
[2140375272] FPS 100 (58-504)
[2140377273] FPS 99 (58-394)
[2140379274] FPS 96 (38-361)
[2140381276] FPS 95 (32-414)
[2140383286] FPS 83 (4-908)
[2140385287] FPS 101 (59-481)
[2140387289] FPS 102 (58-379)
[2140389291] FPS 100 (58-319)
[2140391300] FPS 99 (61-356)
[2140393303] FPS 99 (60-362)
[2140395304] FPS 102 (43-506)
[2140397306] FPS 99 (38-460)
[2140399307] FPS 101 (59-353)
[2140401308] FPS 98 (52-398)
[2140403311] FPS 97 (60-130)
[2140405311] FPS 101 (60-405)
[2140407321] FPS 104 (61-518)
[2140409323] FPS 99 (54-136)
[2140411325] FPS 99 (61-416)
[2140413334] FPS 99 (56-339)
[2140415344] FPS 104 (60-133)
[2140417354] FPS 101 (55-415)
[2140419355] FPS 100 (61-361)
[2140421357] FPS 103 (61-389)
[2140423359] FPS 100 (60-147)
[2140425369] FPS 100 (61-329)
[2140427370] FPS 98 (17-515)
[2140429372] FPS 95 (37-172)
[2140431383] FPS 96 (42-511)
[2140433384] FPS 101 (59-380)
[2140435385] FPS 103 (60-394)
[2140437388] FPS 99 (61-322)

1.5.0

[2140958059] FPS 55 (3-153)
[2140960060] FPS 60 (58-61)
[2140962062] FPS 60 (58-62)
[2140964072] FPS 62 (58-132)
[2140966074] FPS 98 (55-424)
[2140968075] FPS 96 (55-391)
[2140970078] FPS 85 (49-349)
[2140972079] FPS 100 (55-307)
[2140974080] FPS 96 (51-385)
[2140976090] FPS 73 (58-292)
[2140978091] FPS 60 (58-62)
[2140980093] FPS 60 (58-62)
[2140982096] FPS 71 (50-330)
[2140984105] FPS 80 (37-380)
[2140986106] FPS 68 (38-172)
[2140988108] FPS 95 (46-612)
[2140990109] FPS 88 (40-301)
[2140992111] FPS 88 (44-239)
[2140994112] FPS 66 (54-143)
[2140996114] FPS 60 (59-61)
[2140998116] FPS 60 (54-128)
[2141000117] FPS 60 (59-61)
[2141002119] FPS 60 (59-61)
[2141004129] FPS 61 (55-138)
[2141006130] FPS 60 (58-62)
[2141008132] FPS 60 (59-61)
[2141010142] FPS 61 (55-140)
[2141012143] FPS 60 (59-61)
[2141014145] FPS 60 (59-61)
[2141016154] FPS 61 (55-123)
[2141018156] FPS 60 (59-61)
[2141020158] FPS 60 (59-61)
[2141022159] FPS 60 (58-61)
[2141024169] FPS 61 (55-135)
[2141026171] FPS 60 (58-61)
[2141028172] FPS 60 (59-61)
[2141030182] FPS 61 (55-128)
[2141032184] FPS 60 (59-61)
[2141034185] FPS 60 (58-61)
[2141036187] FPS 60 (53-126)
[2141038189] FPS 60 (58-62)
[2141040198] FPS 91 (56-268)
[2141042200] FPS 98 (38-602)
[2141044202] FPS 100 (55-603)
[2141046204] FPS 103 (55-683)
[2141048205] FPS 60 (41-125)
[2141050206] FPS 60 (53-70)

Hypothesis: VRR drops the screen refresh rate to 60Hz if there are no touches on the screen.

[elijah-semyonov]

The most problematic place in this issue was incorrect invalidation logic, it was fixed by JetBrains/compose-multiplatform-core#797