1874040 - Slow performance on https://github.com/public-apis/public-apis compared to Chrome

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Ksenia Berezina [:ksenia]]

​​### Basic information
This was initially reported in https://github.com/webcompat/web-bugs/issues/131302 where a user is experiencing slow page and content load

Steps to Reproduce:

1. Sign in on GitHub
2. Visit https://github.com/public-apis/public-apis

Expected Results:
Page and content loads fast

Actual Results:
Page and content load takes a lot of time

---

Performance recording (profile)

Profile URL: https://share.firefox.dev/3SeCe4V (recorded in Firefox Nightly 123.0a1 (2024-01-02))

System configuration:

OS version: Windows 10, but can be reproduced on other platforms as well

Comment 1

[Bas Schouten (:bas.schouten)]

Emilio has indicated this might be improved by: https://bugzilla.mozilla.org/show_bug.cgi?id=1866161

The Performance Impact Calculator has determined this bug's performance impact to be low. If you'd like to request re-triage, you can reset the Performance Impact flag to "?" or needinfo the triage sheriff.

Platforms: Windows
Impact on site: Causes noticeable jank
Websites affected: Rare
[x] Able to reproduce locally

Comment 2

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

The page loads fast to me in Nightly.
Bug 1866161 landed awhile ago, but I think there was some other fix which landed recently.

Comment 3

[Emilio Cobos Álvarez (:emilio)]

I can reproduce on Nightly.

Comment 4

[Emilio Cobos Álvarez (:emilio)]

Attachment: Attempt at a test-case.

Comment 5

[Emilio Cobos Álvarez (:emilio)]

Comment on attachment 9379220 [details]
Attempt at a test-case.

Meh, that doesn't work. In any case it seems to be this code.

Comment 6

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Setting to S3 because of "performance impact: low". Feel free to upgrade it if this is more important.

Comment 7

[Emilio Cobos Álvarez (:emilio)]

https://treeherder.mozilla.org/perfherder/compare?originalProject=try&originalRevision=1209f491f34d680e2dad836bc9b5a3df0e14e64a&newProject=try&newRevision=4ef9e386d3142a9c21f9c62b11377de022369706

Comment 8

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1874040 - Simplify dir=auto implementation. r=smaug

Make sure to do no work on insertions if the dir=auto element has
already the right strong directionality, but record that the node might
be the one impacting the dir=auto resolution.

Also get some node flags back.

To be landed after merge of course.

Comment 9

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1874040 - Avoid double-negatives in dir=auto code. r=smaug

This is probably because I've been awake for too long at this point
while traveling back from CSSWG meetings, but these make my head
spin.

Let's avoid the double-negatives. I think it's easier to reason
about.

Depends on D202071

Comment 10

[Emilio Cobos Álvarez (:emilio)]

Uh, latest version has some orange on try which I need to fix up.

Comment 11

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1874040 - Move 1103348-1.html to WPT, and expand it. r=smaug

This test caught a subtle bug in one of the versions of my previous
patch, but it caught it by chance.

The reason it got caught is because the reftest harness uses a mutation
observer, and thus disables the textContent optimization that reuses the
text node.

WPT didn't catch this, so move the test there, and add tests for the
characterData mutation and removal-and-append explicitly, to not depend
on textContent optimizations.

Comment 12

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4ce4c83e0d85
Move 1103348-1.html to WPT, and expand it. r=smaug

Comment 13

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/44697 for changes under testing/web-platform/tests

Comment 14

[Emilio Cobos Álvarez (:emilio)]

Latest numbers: https://treeherder.mozilla.org/perfherder/compare?originalProject=try&originalRevision=9c64af7900136e414fe22841d172adc690026624&newProject=try&newRevision=cf7d14e0372c23231998c111525688b20a6dba32&page=1&framework=13

Comment 15

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ddd358fef977
Simplify dir=auto implementation. r=smaug

Comment 16

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/4ce4c83e0d85
https://hg.mozilla.org/mozilla-central/rev/ddd358fef977

Comment 17

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot