1840424 - Add time zone cache for Temporal

Status: RESOLVED FIXED

(Core :: JavaScript: Standard Library, task, P3)

Description

[André Bargull [:anba]]

Bug 1840374 adds support for string time zones, but doesn't include any time zone cache. The ability to cache built-in time zones was a main motivation for supporting string time zones. See also https://github.com/tc39/proposal-temporal/pull/2482.

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1840424 - Part 1: Cache the default time zone object. r=#spidermonkey-reviewers!

Add a global cache for the default time zone object. This avoids creating
new ICU time zone objects when using the default time zone in Temporal
code.

Comment 2

[André Bargull [:anba]]

Attachment: Bug 1840424 - Part 2: Add a one element cache for time zone objects. r=#spidermonkey-reviewers!

In addition to caching the default time zone, also add a one element cache for
named time zones. A one element cache is enough for simple test cases like in
bug 1961480.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/58c652ad58bd
https://hg.mozilla.org/integration/autoland/rev/c06722b43455
Part 1: Cache the default time zone object. r=spidermonkey-reviewers,dminor
https://github.com/mozilla-firefox/firefox/commit/d403b4811f9d
https://hg.mozilla.org/integration/autoland/rev/581b3e6ae4f5
Part 2: Add a one element cache for time zone objects. r=spidermonkey-reviewers,dminor

Comment 4

[[e-mail]]

Backed out for causing SM bustages failures at DateTime.h
- Backout link

- Push with failures

- Failure log

• Failure line:
  /builds/worker/checkouts/gecko/js/src/vm/DateTime.h:73:27: error: no member named 'intl' in namespace 'mozilla'

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/481606b34941
https://hg.mozilla.org/integration/autoland/rev/8b4161ded993
Part 1: Cache the default time zone object. r=spidermonkey-reviewers,dminor
https://github.com/mozilla-firefox/firefox/commit/e2781c359c93
https://hg.mozilla.org/integration/autoland/rev/f61251bca4fc
Part 2: Add a one element cache for time zone objects. r=spidermonkey-reviewers,dminor

Comment 6

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/8b4161ded993
https://hg.mozilla.org/mozilla-central/rev/f61251bca4fc

Comment 7

[Acasandrei Beatrice (needinfo me)]

(In reply to Pulsebot from comment #5)

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/481606b34941
https://hg.mozilla.org/integration/autoland/rev/8b4161ded993
Part 1: Cache the default time zone object. r=spidermonkey-reviewers,dminor
https://github.com/mozilla-firefox/firefox/commit/e2781c359c93
https://hg.mozilla.org/integration/autoland/rev/f61251bca4fc
Part 2: Add a one element cache for time zone objects.
r=spidermonkey-reviewers,dminor

Perfherder has detected a awsy performance change caused either by this bug or Bug 1839682 or Bug 1974378.

If you have any questions, please reach out to a performance sheriff. Alternatively, you can find help on Slack by joining #perf-help, and on Matrix you can find help by joining #perftest.

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)
0.28%	Base Content JS	macosx1470-64-shippable	fission	1,553,138.67 -> 1,548,770.67
0.28%	Base Content JS	linux1804-64-shippable-qr	fission	1,555,032.00 -> 1,550,664.00
0.28%	Base Content JS	windows11-64-24h2-shippable	fission	1,561,160.00 -> 1,556,792.00

Details of the alert can be found in the alert summary, including links to graphs and comparisons for each of the affected tests.

If you need the profiling jobs you can trigger them yourself from treeherder job view or ask a performance sheriff to do that for you.

You can run all of these tests on try with ./mach try perf --alert 45916

The following documentation link provides more information about this command.