1680234 - Accelerate font fallback by avoiding freetype face creation where possible

Status: RESOLVED FIXED

(Core :: Graphics: Text, defect)

Description

[Jonathan Kew [:jfkthame]]

This is similar to bug 1614600, where using harfbuzz APIs in preference to freetype improved the performance of initializing the font list.

A similar issue applies when we're doing font fallback searches; if there are fonts for which we don't have an FT_Face already on hand, it's expensive to instantiate this just to check if the font has the character coverage we need. We can do better (as confirmed by Andrew's profiling in bug 1676966 comment 21) by avoiding freetype and reading the fonts using harfbuzz APIs instead.

Comment 1

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1680234 - Accelerate global font fallback on Android by avoiding freetype face creation where possible. r=lsalzman

Comment 2

[Andrew Creskey [:acreskey]]

In Bug 1676966, comment 14 I compared this change, fenix_harfbuzz_only to the baseline fenix and it showed significant improvements to visual metrics on certain sites (Pixel 3).

I've captured a few profiles, and as expected, I don't see any jank in the parent process, since we've improved the font face creation.
e.g.
https://share.firefox.dev/2Vu34Yg

I'll also compare this on a lower-end phone.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0a01bf877df8
Accelerate global font fallback on Android by avoiding freetype face creation where possible. r=lsalzman

Comment 4

[Andrew Creskey [:acreskey]]

Attachment: Results on G5

This patch also shows a measurable improvement on the lower-end Moto G5.

These are live sites so there is a fair deal of noise, but this looks like:
~7-8% speedIndex improvement on accounts.google
~12-13% speedIndex improvement on wikipedia.

More metrics here:
https://docs.google.com/spreadsheets/d/1FjhbYxNH37FZCeJiBcz2_pH7KmXvkiclV2ppQGz3jes/edit#gid=1430810009

It will be interesting to see if this picks up anything in the geckoview browsertime tests.

Comment 5

[Andrew Creskey [:acreskey]]

To compare against what browsertime in CI picks up:
On Pixel 3 I'm seeing

~10% speedindex improvement on accounts.google.com
~29% speedindex improvement on wikipedia.org

https://docs.google.com/spreadsheets/d/1FjhbYxNH37FZCeJiBcz2_pH7KmXvkiclV2ppQGz3jes/edit#gid=1092288141&range=W40:W47

Comment 6

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/0a01bf877df8