servo/tests/blink_perf_tests/perf_tests/css/ChangeStyleCSSVariableRecalc.html
Jonathan Schwender ee781b71b4
tests: Vendor blink perf tests (#38654)
Vendors the [blink perf
tests](https://chromium.googlesource.com/chromium/src/+/HEAD/third_party/blink/perf_tests/).
These perf tests are useful to evaluate the performance of servo. 
The license that governs the perf tests is included in the folder. 
Running benchmark cases automatically is left to future work.

The update.py script is taken from mozjs and slightly adapted, so we can
easily filter
(and patch if this should be necessary in the future.

Testing: This PR just adds the perf_tests, but does not use or modify
them in any way.

---------

Signed-off-by: Jonathan Schwender <schwenderjonathan@gmail.com>
2025-08-17 09:54:04 +00:00

98 lines
3.3 KiB
HTML
Vendored

<!DOCTYPE html>
<head>
<title>CSS Custom Properties and Variables: Changes that require resolving variable references</title>
<script src="../resources/runner.js"></script>
<script src="resources/utils.js"></script>
</head>
<style>
.container > div {
display: inline-block;
height: 14px;
width: 14px;
box-sizing: border-box;
border: 1px solid green;
}
.container {
height: 0px;
overflow: hidden;
}
</style>
<body>
<header id=info>CSS Variables: <button id=button></button></header>
<script>
const NUM_ELEMENTS = 20000;
const PROP_COUNT = 1000;
let curBorder = -1;
let root = document.createElement('div');
root.classList.add(`container`);
// Add ?ref to URL to run a similar test without CSS Variables.
const ref = document.location.href.endsWith('?ref');
button.textContent = ref ? 'OFF' : 'ON';
button.addEventListener('click', function(){
let href = document.location.href;
if (ref) {
document.location.href = href.substr(0, href.length - 4);
} else {
document.location.href = href + '?ref';
}
});
function hexcolor(i) {
let hex = i.toString(16);
while (hex.length < 6)
hex = '0' + hex;
return '#' + hex;
}
function createDOMTree() {
for (let n = 0; n < NUM_ELEMENTS; n++) {
let div = document.createElement('div');
let i = n % PROP_COUNT;
div.classList.add(`bg-color${i}`);
root.appendChild(div);
}
document.body.appendChild(root);
}
function createDivRules() {
let lines = [];
for (let i = 0; i < PROP_COUNT; i++) {
lines.push(`.border${i} > div { border-color: ${hexcolor(i)}; }`);
if (ref)
lines.push(`.bg-color${i} { background-color: ${hexcolor(i)}; }`);
else
lines.push(`.bg-color${i} { background-color: var(--prop-${i}); }`);
}
return lines.join('\n');
}
// Create a rule which defines 'propCount' custom properties at :root.
function createRootRule() {
if (ref)
return;
let lines = [':root {'];
for (let i = 0; i < PROP_COUNT; i++) {
lines.push(`--prop-${i}: ${hexcolor(i)};`);
}
lines.push('}');
return lines.join('\n');
}
applyCSSRule(createDivRules());
applyCSSRule(createRootRule());
createDOMTree();
PerfTestRunner.measureTime({
description: "Measures the performance of the CSS variable reference recalc.",
setup: () => {
root.classList.remove(`border${curBorder}`);
// Using PROP_COUNT to ensure different border values, avoiding the style cache
curBorder = (curBorder + 1) % PROP_COUNT;
},
run: function() {
root.classList.add(`border${curBorder}`);
forceStyleRecalc(document.body);
},
});
</script>
</body>