1568932 - Address settle-time regression from optimistic loading

Status: VERIFIED FIXED

(Firefox :: New Tab Page, task, P1)

Comment 1

[Gavin Suntop [:gvn] (they/them)]

Either roll back entirely or wait until after initial layout has settled to start optimistic preloading.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

Bugbug thinks this bug is a task, but please change it back in case of error.

Comment 3

[Scott [:thecount] Downe]

[Tracking Requested - why for this release]: Performance regression.

Comment 4

[GitHub Bugzilla PR Linker]

Attachment: Link to GitHub pull-request: https://github.com/mozilla/activity-stream/pull/5204

Comment 5

[GitHub Bugzilla PR Linker]

Attachment: Link to GitHub pull-request: https://github.com/mozilla/activity-stream/pull/5210

Comment 6

[Ciprian Muresan [:cmuresan], Ecosystem QA]

https://hg.mozilla.org/mozilla-central/rev/49f075579f00

Comment 7

[Scott [:thecount] Downe]

Attachment: Uplift 1568932 - reverting PR #5111 due to perf regression (#5210)

Comment 8

[Scott [:thecount] Downe]

Comment on attachment 9084024 [details]
Uplift 1568932 - reverting PR #5111 due to perf regression (#5210)

Beta/Release Uplift Approval Request

• User impact if declined: UX and revenue impact because of performance regression.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: 1. Load a new tab page.

2. Set network in devtools to GPRS
3. Scroll down until you start seeing more images loading.

Images should start loading as soon as 1 pixel comes into view.
Without this, images would start to load 200 pixels before the image comes into view. With GPRS set, you can scroll just before an image, and wait, then see if an image has started to load.

• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): It's a revert to older functionality, and it's also really small.
• String changes made/needed: none

Comment 9

[Marius Coman [:mcoman], Ecosystem QA]

I have verified this issue with the latest Firefox Nightly (70.0a1 Build ID - 20190808214929) installed, on Windows 10 x64, Arch Linux and Mac 10.14.5. Now, an image starts to load only after it comes into view.

Comment 10

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9084024 [details]
Uplift 1568932 - reverting PR #5111 due to perf regression (#5210)

Reverts us back to older behavior to fix a perf regression on the New Tab Page. Approved for 69.0b13.

Comment 11

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/releases/mozilla-beta/rev/d3d2b884f3b8

Comment 12

[Marius Coman [:mcoman], Ecosystem QA]

I have verified this issue with the latest Firefox Beta (69.0b13 Build ID - 20190812173625) installed, on Windows 10 x64, Arch Linux and Mac 10.14.5. Now, an image starts to load only after it comes into view.