1974519 - Preserve DOM Wrappers from JIT code

Status: RESOLVED FIXED

(Core :: JavaScript Engine, task, P2)

Description

[Alex Thayer [:alexical] (she/her)]

This bug covers deferring DOM wrapper preservation via an intermediate buffer and allowing us to write to that buffer from the JIT to avoid having to call into Gecko for first property adds on DOM wrappers.

Comment 1

[Alex Thayer [:alexical] (she/her)]

Attachment: Bug 1974519 - Defer DOM wrapper preservation until necessary r?jonco

The main objective of this patch is to allow us to interact with DOM wrapper
preservation directly from the JIT, which it does by creating a deferred wrapper
preservation buffer which is consumed before any GC. The patch after this
handles writing to this buffer from the JIT where necessary.

Comment 2

[Alex Thayer [:alexical] (she/her)]

Attachment: Bug 1974519 - Preserve DOM wrappers from the JIT r?jandem

This patch handles writing to the deferred wrapper preservation buffer introduced
by the previous patch from JIT code.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/04e2ad063b5a
https://hg.mozilla.org/integration/autoland/rev/09871ecf75b8
Defer DOM wrapper preservation until necessary r=jonco
https://github.com/mozilla-firefox/firefox/commit/343da25eba71
https://hg.mozilla.org/integration/autoland/rev/95099f2fb81b
Preserve DOM wrappers from the JIT r=jandem

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/ef09549c2464
https://hg.mozilla.org/integration/autoland/rev/987199e08e85
Revert "Bug 1974519 - Preserve DOM wrappers from the JIT r=jandem" for causing mass failures.

Comment 5

[agoloman]

Backed out for causing mass failures.

• Backout link
• Push with failures
• Failure Log

Comment 6

[Alex Thayer [:alexical] (she/her)]

Attachment: Bug 1974519 - Fix DOM wrapper ops in pbl r?jandem

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/43ffb6999d70
https://hg.mozilla.org/integration/autoland/rev/ddd4bfa0111b
Defer DOM wrapper preservation until necessary r=jonco
https://github.com/mozilla-firefox/firefox/commit/4e9f2733073a
https://hg.mozilla.org/integration/autoland/rev/b52f931b202b
Preserve DOM wrappers from the JIT r=jandem
https://github.com/mozilla-firefox/firefox/commit/4fd8d7d94977
https://hg.mozilla.org/integration/autoland/rev/23cb51d62173
Fix DOM wrapper ops in pbl r=jandem

Comment 8

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/ddd4bfa0111b
https://hg.mozilla.org/mozilla-central/rev/b52f931b202b
https://hg.mozilla.org/mozilla-central/rev/23cb51d62173

Comment 9

[Florin Bilt]

(In reply to Cosmin Sabou [:CosminS] from comment #8)

https://hg.mozilla.org/mozilla-central/rev/ddd4bfa0111b
https://hg.mozilla.org/mozilla-central/rev/b52f931b202b
https://hg.mozilla.org/mozilla-central/rev/23cb51d62173

Perfherder has detected a browsertime performance change from push 23cb51d6217342d39cc2e0dfb16866d76541d614.

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)
3%	speedometer3 Charts-observable-plot/Dotted/Sync	android-hw-a55-14-0-aarch64-shippable	webrender	17.75 -> 17.30
2%	speedometer3 Charts-observable-plot/Stacked by 20/Sync	android-hw-a55-14-0-aarch64-shippable	webrender	39.37 -> 38.53

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 46470

The following documentation link provides more information about this command.

Comment 10

[Alex Thayer [:alexical] (she/her)]

Hmm, I was definitely expecting a bigger impact than this given several preliminary try runs of the patches in development. I'm going to try rerunning with some of the older patches to make sure nothing was lost along the way.