1660692 - calDateTimeFormatter.inTimezone could be more efficient

Status: RESOLVED FIXED

(Calendar :: Internal Components, defect)

Description

[Mark Banner (:standard8)]

I'm working on adding a test for the amount of accesses of preferences on startup. I noticed that intl.regional_prefs.use_os_locales is access about 100 times.

A lot of these accesses (~90) are via calDateTimeFormatter#inTimezone -> MozDateTimeFormat -> getLocales.

The obvious issue is that the formatter might be constructed twice if the date has a timezone, this should be able to be avoided.

The other thing that might be possible is to cache the formatter in the calls to inTimezone. This might, of course, depend on how frequently the timezone might be different, but would at least give some possibilities for improvement when it is all the same.

Comment 1

[Wayne Mery (:wsmwk)]

Would you expect this to have only minor performance impact, i.e. not likely to be noticeable by itself, <2sec?

Comment 2

[Mark Banner (:standard8)]

(In reply to Wayne Mery (:wsmwk) from comment #1)

Would you expect this to have only minor performance impact, i.e. not likely to be noticeable by itself, <2sec?

Probably not noticeable by itself, but would definitely be worth doing as part of general startup performance and probably application performance.

Comment 3

[Geoff Lankow (:darktrojan)]

Attachment: Bug 1660692 - Remove intl.regional_prefs.use_os_locales from the list of problematic start-up prefs. r?Standard8

Bug 1635561 has dramatically improved the count.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/comm-central/rev/bd4299747089
Remove intl.regional_prefs.use_os_locales from the list of problematic start-up prefs. r=Standard8

Comment 5

[Geoff Lankow (:darktrojan)]

Ah, spoke too soon. Bug 1635561 did improve the count, but that's because it didn't work properly. Back to square one here.

Comment 6

[Geoff Lankow (:darktrojan)]

Backed out:
https://hg.mozilla.org/comm-central/rev/4c5bea8b0b13d2fdb7e98f42a530b5ca65060286

Comment 7

[Intermittent Failures Robot]

1 failures in 4060 pushes (0.0 failures/push) were associated with this bug in the last 7 days.

Repository breakdown:

• comm-central: 1

Platform breakdown:

• linux64: 1

For more details, see:
https://treeherder.mozilla.org/intermittent-failures/bugdetails?bug=1660692&startday=2020-12-07&endday=2020-12-13&tree=all

Comment 8

[Geoff Lankow (:darktrojan)]

Attachment: Bug 1660692 - Prevent redundant calls to new Services.intl.DateTimeFormat and preferences service in hot code paths. r?mkmelin

In testing, this saves thousands of calls to new Services.intl.DateTimeFormat and hundreds of calls to the preferences service.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/comm-central/rev/f6f7743a893b
Prevent redundant calls to new Services.intl.DateTimeFormat and preferences service in hot code paths. r=mkmelin