1818830 - escape() from react-dom seems slower in SM than V8 and JSC

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P3)

Description

[Jeff Muizelaar [:jrmuizel]]

Attachment: escape.js

escape:

function escape(key) {
    var escaperLookup = {
        "=": "=0",
        ":": "=2"
    };
    return "$" + ("" + key).replace(/[=:]/g, function(match) {
        return escaperLookup[match];
    });
}

On the attached benchmark I get:
SM w/ spectre-mitigations off: 38ms
V8: 25ms
JSC: 38ms

The keys used in the benchmark are taken from react-todoMVC

Comment 1

[Jeff Muizelaar [:jrmuizel]]

SM profile: https://share.firefox.dev/3ZgPeYc
V8 profile: https://share.firefox.dev/3Z0gCdo

Comment 2

[Jeff Muizelaar [:jrmuizel]]

JSC profile: https://share.firefox.dev/3xQh3eh

Comment 3

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

Assigning myself just because I am working on a patch that will indirectly fix this.

Comment 4

[Matthew Gaudet (he/him) [:mgaudet]]

We've done a bit of work in related areas; how's the performance gap now?

Comment 5

[Mayank Bansal]

original testcase:

• Chrome: 11ms (https://share.firefox.dev/3Cm8DRO)
• Nightly: 10ms-12ms (https://share.firefox.dev/3ElizeJ)

10x loopcpunt

• Chrome: 100ms (https://share.firefox.dev/3Cdy7Rp)
• Nightly: 100ms https://share.firefox.dev/4jz3IO0

100x loopcount

• Chrome: 1050ms (https://share.firefox.dev/4hxRzay)
• Nightly: 950ms-1000ms (https://share.firefox.dev/4gda1UH)

Worth keeping this open?

Comment 6

[Iain Ireland [:iain]]

Looks fixed to me!