1944091 - Bugzilla's favicon is many times larger than typical websites' favicons, and its size causes noticeable jank in Firefox for heavy bugzilla users

Status: RESOLVED FIXED

(bugzilla.mozilla.org :: User Interface, defect)

Description

[Daniel Holbert [:dholbert]]

Bugzilla's favicon is 140KB, which is quite large relative to other favicons of popular sites. Can we bring that size down by a factor of 10 or so (to e.g. 14KB or therabouts)?

For comparison, here's the favicon that gets used on my machine on various other popular sites:

• TaoBao' favicon is 20KB (dimensions: 64x64)
• Reddit's favicon is 4KB (dimensions: 64x64)
• Google's favicon is 8KB (dimensions: 32x32)
• Zoom's favicon is 8KB (dimensions: 32x32)
• Instagram's favicon is 4KB (dimensions: 32x32)

So: bugzilla's favicon is many times bigger (in terms of bytes) than all these sites' favicons (7x the TaoBao favicon size, 35x the Reddit/Instagram favicon size).

This causes problems because:
(1) In Firefox, favicons incur some amount of performance cost for each tab that's using them (for now at least)
(2) Firefox developers tend to have many copies of bugzilla open in various tabs (maybe on the order of hundreds), either as part of their daily work (as a sort of to-do list, or things to cycle back to,) or as part of temporary deep-dives.
(3) As a result of (1) and (2), certain operations in Firefox can take on the order of several seconds for heavy Bugzilla users, when they're expected to be ~instantaneous.

The per-tab costs (labeled (1) above) are worth investigating and addressing; but in the meantime we could also bring down the costs by an order of magnitude or so if we simply reduced the size of the favicon that we use for BMO.

Comment 1

[Daniel Holbert [:dholbert]]

Note: here's how I got the favicon sizes that I reported above -- they're inexact (due to du -sh rounding) but close enough:

• enable Browser Toolbox
• Inspect a favicon in Firefox's tab strip, and find the node that has the image URI.
• Copy the data-URI-encoded representation of the favicon, and view that directly.
• Save the image to a file and do du -sh on the file to get its on-disk size.

Comment 2

[Daniel Holbert [:dholbert]]

(In reply to Daniel Holbert [:dholbert] from comment #0)

This causes problems because:
(1) In Firefox, favicons incur some amount of performance cost for each tab that's using them (for now at least)

• One instance of this^ is bug 1849393 (particularly my dupe bug 1867161) which is about our periodic sessionrestore write-to-disk, where heavyweight favicons make that process much more expensive (causing Firefox to jank every 15 seconds).
• Another instance is a bug that I ran across today that I'm about to file [EDIT: filed bug 1944111] about the "List all tabs" menu (the downarrow at the right edge of the tab-strip).
• (basically this is troublesome for anything that requires us to serialize or render all of a window's tabs at once).

Comment 3

[Daniel Holbert [:dholbert]]

BTW it looks like the current favicon was probably added in bug 1241904. Adding a dependency on that bug to reflect that connection.

Comment 4

[BMO Github Automation]

Attachment: [mozilla-bteam/bmo] Bug 1944091 - shrink favicon (#2382)

Comment 5

[David Lawrence [:dkl]]

Merged
https://github.com/mozilla-bteam/bmo/commit/040e86b3f883aecfbfad6936d89caf832e2a7913

Comment 6

[Daniel Holbert [:dholbert]]

Thanks! du says the new favicon is 8KB -- awesome.