90761 - why are we missing the font cache?

Status: RESOLVED INVALID

(Core :: Graphics, defect, P2)

Description

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

I just took a profile of a run through ibench, and I'm getting the feeling we're
missing the font cache a lot.  In particular, we're missing the font cache
during paint, which scares me, since it should be cached from reflow.

The push-to-the-front-of-the-list code could also be optimized by using the end
of the list as the front and *leaving* the AppendElement that we perhaps should
have changed before.

Comment 1

[Randell Jesup [:jesup] (needinfo me)]

I think I've found the problem in bug 91956.  I'm going to dup this into that
one.

*** This bug has been marked as a duplicate of 91956 ***

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

It was known that the lifetime of the font cache was short, but this says we're
missing it even within that short lifetime.

I've been thinking that the font cache needs to be at a lower level since the
font code for each port knows which strings result in equivalent fonts.

Reopening.

Comment 3

[kill this account]

from bug 91956
> ...
> Note that on Unix, the underlying font engine uses a single font cache, so we
> are not calling the OS too many times for each nsFont 

True, the Linux/Unix code only opens each X font once and (cough, cough) never 
(cough, cough) releases it.

However, the Linux/Unix font code does spend a *lot* of time building the
mLoadedFonts list (used for glyph fill in) when a font cache entry is created. 
So every time an entry in the font cache is cleared and then recreated the 
mLoadedFonts list has to be rebuilt.

Comment 4

[Cathleen]

this might be a performance win, but don't know how much.
so, taking this off nsbeta1 list.

Comment 5

[Marco Castelluccio [:marco]]

I think this will be resolved when this other bug (https://bugzilla.mozilla.org/show_bug.cgi?id=91956) will be resolved.

Comment 6

[Joe Drew (not getting mail)]

I don't think that this has any relevance any more; please reopen if I'm wrong.

Comment 7

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Well, we still have the font cache; whether we should is another question.

Comment 8

[Randell Jesup [:jesup] (needinfo me)]

How about we fix bug 91956, and then this one really will be invalid?  It sounds like after 10 years, that one might actually get fixed, so...  Bug :zwol!