1538516 - Resolve the Promise returned by fetch() later during page loads

Status: RESOLVED FIXED

(Core :: DOM: Networking, defect, P2)

Description

[Olli Pettay [:smaug][[e-mail]]]

Similarly to bug 1538364.

Comment 1

[Honza Bambas (:mayhemer)]

Just FYI, if the fetch() delivers a "highly visible content" *), or is on the path to deliver it to the screen, it may actually lead to a regression in perceived load perf.

*) highly visible content = e.g. a large image in the middle of the screen, a featured image of an article, a dynamic gallery...

I was struck by that few times when I was tuning the tailing feature and why I made the delay to keep tailed requests queued way shorter after domcontentloaded event.

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

Sure. This is a tricky case. But as bug 1538364 hints, and bug 1270059 too, using idle-or-right-after-load approach may help quite a bit in certain cases.

Comment 3

[Honza Bambas (:mayhemer)]

Will there be studies for any of those changes?

Comment 4

[Olli Pettay [:smaug][[e-mail]]]

Attachment: wip for testing

Just a patch for testing whether this could help with page loads.
(I think it does help with buzzfeed)

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

Base: https://treeherder.mozilla.org/#/jobs?repo=try&revision=9d5e99e7dc7cda45f331c262e5325d8429d1614d
Patch: https://treeherder.mozilla.org/#/jobs?repo=try&revision=7e3fefc3388a50f11217aa0e53ed88d265697371

Comment 6

[Olli Pettay [:smaug][[e-mail]]]

Attachment: Bug 1538516 - Resolve the Promise returned by fetch() later during page loads, r=baku

The patch depends on https://bugzilla.mozilla.org/show_bug.cgi?id=1558215

Depends on D34366

Comment 7

[Olli Pettay [:smaug][[e-mail]]]

build https://treeherder.mozilla.org/#/jobs?repo=try&revision=8656e5bd1bf9278140783f19739a177f5d8042e5
raptor https://treeherder.mozilla.org/#/jobs?repo=try&revision=47def924b7881cf7a30cf427851832de0685ef18

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7ba9d3d60a93
Resolve the Promise returned by fetch() later during page loads, r=baku

Comment 9

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/7ba9d3d60a93

Comment 10

[Kohei Yoshino [:kohei]]

Posted site compatibility note: https://www.fxsitecompat.dev/en-CA/docs/2019/resolving-promise-returned-by-fetch-is-now-deferred-during-page-load/