1736868 - A gfxFontCache::gfxFontCache timer wakes up idle content processes every 60s

Status: RESOLVED FIXED

(Core :: Layout: Text and Fonts, defect)

Description

[Florian Quèze [:florian]]

Here's a profile of a preallocated content process being woken up twice by the this gfxFontCache timer: https://share.firefox.dev/3Bb88U9

It looks like this timer was added in bug 703100 (10 years ago!). This was probably fine when we had few content processes (or maybe this was even before e10s), but now that we have potentially many content processes with Fission, this repeating timer causes lots of wake ups.

Could this timer be stopped when the cache is empty?

Comment 1

[Florian Quèze [:florian]]

It's more visible on a longer profile: https://share.firefox.dev/2Z6jID1

Comment 2

[Chris Peterson [:cpeterson]]

Restoring the block of bug 1689164. This gfxFontCache timer bug is affecting Fission's preallocated processes, but doesn't need to block the Fission MVP release.

Comment 3

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1736868 - Pause the word-cache expiration timer when all caches are empty. r=lsalzman

This avoids periodically waking up an otherwise-idle process once we've expired all the
cached-word entries.

Also reduce the font and shaped-word expiration times somewhat, so that processes will tend to
become idle sooner. In practice if we don't reuse a given record within seconds, it's probably
not critical to performance; the caches are primarily there for when the same font is used for
many elements of a page, or a page is reflowed several times during load.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b53f13244266
Pause the word-cache expiration timer when all caches are empty. r=lsalzman

Comment 5

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/b53f13244266

Comment 6

[Chris Peterson [:cpeterson]]

Setting status-firefox94=wontfix because it's too late to uplift to Beta 94.