1016483 - 50ms Settings Startup Time Regression

Status: RESOLVED FIXED

(Firefox OS Graveyard :: Gaia::System::Window Mgmt, defect, P1)

Description

[Mason Chang [Inactive] [:mchang]]

We have a 50ms settings startup time regression with commit:

3bca75fd7ba78b687f5869e34e4ed998acf1c515
https://github.com/mozilla-b2g/gaia/commit/3bca75fd7ba78b687f5869e34e4ed998acf1c515

Commit before:
9c34f28aa8e11a0ac90fd2d150e5bfe6a05d3144
Results for Settings, cold_load_time: median:824, mean:827, std: 29, max:901, min:783, all:896,810,837,866,848,783,784,818,799,825,786,815,872,817,850,797,827,792,825,901,829,803,809,838,817,821,868,833,823,834

bad gaia - 3bca75fd7ba78b687f5869e34e4ed998acf1c515
Results for Settings, cold_load_time: median:858, mean:856, std: 25, max:896, min:812, all:859,871,833,825,889,819,870,840,872,820,878,839,854,858,832,847,816,812,828,896,874,831,879,849,864,895,876,879,891,894

Tested on Gecko mozilla-central: b5bdc1aaf378, tested on a Flame. I've been running start up tests every Gaia check in, and the mean went from ~820 to ~860 for startup on the settings app.

Comment 1

[Mason Chang [Inactive] [:mchang]]

Attachment: Regression Fix

Removing the will change and transform help with start up time here:

with changes
Results for Settings, cold_load_time: median:823, mean:825, std: 24, max:898, min:793, all:803,829,819,793,828,826,815,845,794,823,804,809,803,823,831,846,795,804,824,898,894,814,835,822,859,837,808,843,808,824

Results for Settings, cold_load_time: median:807, mean:816, std: 25, max:877, min:755, all:831,807,814,803,804,822,844,822,859,803,826,822,851,800,807,797,755,853,791,860,801,804,805,804,788,877,805,801,836,807

Etienne: Any reason you have both will-change and transform here? Or some other way around it? Thanks!

Comment 2

[Benoit Girard (:BenWa)]

(In reply to Mason Chang [:mchang] from comment #1)
> Etienne: Any reason you have both will-change and transform here? Or some
> other way around it? Thanks!

Yes, that's perfectly fine. As long as the transform will change. If we're not expecting that to happen near the startup then we can app will-change after startup.

Comment 3

[Etienne Segonzac (:etienne)]

Attachment: PR

We keep moving this around :)
We reflow/repaint when we change it, causing various perf issues depending on *when* we change it.
(the proposed fixed is probably making the edge gestures pretty janky)

I'd like to keep it on the base .appWindow class since we know the transform will change.

But maybe we should take advantage of this fact and remove the expensive restyle caused by the #screen.edges class toggle. This is what this patch does, it should compensate the launch time regression.

Can you confirm this?

Comment 4

[Mason Chang [Inactive] [:mchang]]

Comment on attachment 8429978 [details] [review]
PR

Looks good, saves 50ms.

Settings tip - 0e46099b1f4b923f4734518e85e70f754428cf9e
Results for Settings, cold_load_time: median:1966, mean:1966, std: 28, max:2021, min:1854, all:1989,1960,1971,1949,1972,1854,1977,1964,1963,1949,1940,1990,1969,1993,1951,1966,2021,1982,1930,1997,1961,1980,2001,1954,1967,1960,1996,1953,1963,1981

Settings tip w/ fix:
Results for Settings, cold_load_time: median:1914, mean:1918, std: 36, max:2089, min:1880, all:1907,1918,1925,1936,1914,1920,1890,1910,1967,1880,1932,1913,1909,1901,1896,1899,1890,1917,1922,1918,1915,1909,1934,1933,2089,1903,1917,1886,1928,1890

Comment 5

[Etienne Segonzac (:etienne)]

Comment on attachment 8429978 [details] [review]
PR

Cool, moving to review.

Comment 6

[Etienne Segonzac (:etienne)]

https://github.com/mozilla-b2g/gaia/commit/5cc10cfba8a4522ebb82b7aaf1a6cc5887b1b9fb

Comment 8

[Tim Guan-tin Chien [:timdream] (please needinfo)]

Update information to tell what's actually landed.