Closed Bug 1821165 Opened 3 years ago Closed 3 years ago

EmberJS-TodoMVC spends a lot more time in ensureUniqueKey than in V8, due to SetElementMegamorphic

Categories

(Core :: JavaScript Engine, task, P2)

Product:
Core
Component:
JavaScript Engine
Type:
task

Tracking

()

Status:
RESOLVED WONTFIX

People

(Reporter: mstange, Unassigned)

Details

We spend 1945 samples (excluding callees) as opposed to V8's 649 samples in the function ensureUniqueKey in the EmberJS-TodoMVC benchmark.

968 of those samples are spent in SetElementMegamorphic.
V8 spends 135 samples in Builtin:KeyedStoreIC_Megamorphic and 292 samples in v8::internal::Runtime_AddDictionaryProperty.

Profiles (focused on ensureUniqueKey's "JS-only self time"):
Spidermonkey: https://share.firefox.dev/3Zx9Qw1
V8: https://share.firefox.dev/3J0oc0U

To reproduce, run index.js inside https://github.com/mozilla/Speedometer/tree/6e6656a62fd41fd8cfbedefc1df4f05c84e7bff5/resources/todomvc/architecture-examples/emberjs/dist in the JS shell.

Blocks: 1801194
Type: defect → task
Priority: -- → P2

EmberJS has been removed from sp3. Does the issue show up in other tests?

Flags: needinfo?(mstange.moz)

Potentially, but I'll file new bugs once I find one that's worthwhile to optimize.

No longer blocks: speedometer3, 1801194
Status: NEW → RESOLVED
Closed: 3 years ago
Flags: needinfo?(mstange.moz)
Resolution: --- → WONTFIX
Whiteboard: [sp3]
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