script: Start a performance timeline entry for iframe documents#42270
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mrobinson merged 4 commits intoservo:mainfrom Feb 3, 2026
Merged
script: Start a performance timeline entry for iframe documents#42270mrobinson merged 4 commits intoservo:mainfrom
mrobinson merged 4 commits intoservo:mainfrom
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jdm
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Feb 1, 2026
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| // TODO 2-4 Mark resource timing. | ||
| // Mark resource timing. | ||
| let document = match ScriptThread::find_document(loaded_pipeline) { |
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Step 4.1 says to use the iframe's node document, which is self.owner_document(). Right now we're getting the equivalent of child document from the specification.
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I noticed Chrome, Brave and Firefox do not have the iframe PerformanceResourceTiming entries and thought I might have misunderstood the task
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Are other browsers also supposed to record the entry like on the tests?
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I would expect all browsers to do it. We can verify that the tests are passing in other browsers on wpt.fyi.
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Huh, whatwg/html#12122 (comment) means that I haven't correctly understood the algorithm we're completing. I'll try to take a look at this tonight to figure out what we're missing.
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Ok, I see how the pieces are supposed to fit together now. There is:
- https://html.spec.whatwg.org/multipage/browsing-the-web.html#create-navigation-params-by-fetching (step 10.3) which sets an initiator type for the iframe navigation request
- https://fetch.spec.whatwg.org/#fetch-finale (step 4.2.8) when the request has an initiator type
However, there is also the Timing Allow Origin (TAO) check, which controls how much data the containing document is allowed to see about the request:
- https://fetch.spec.whatwg.org/#concept-tao-check
- https://fetch.spec.whatwg.org/#ref-for-concept-tao-check
The code we're modifying in this PR is a fallback for when the TAO check fails, ensuring there an entry populated with very basic timing information:
- https://html.spec.whatwg.org/multipage/browsing-the-web.html#populating-a-session-history-entry:iframe-pending-resource-timing-start-time
- https://html.spec.whatwg.org/multipage/iframe-embed-object.html#the-iframe-element:iframe-pending-resource-timing-start-time
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A quick minimal testcase (the referenced t.html can just be an empty document):
<script>
function dump() {
const resources = performance.getEntriesByType("resource");
resources.forEach((entry) => {
console.log(entry);
});
console.log ("---");
const navs = performance.getEntriesByType("navigation");
navs.forEach((entry) => {
console.log(entry);
});
};
function load() {
setTimeout(dump, 0);
}
</script>
<iframe onload="load()" src="t.html"></iframe>In Firefox this shows a resource timing entry for t.html and a navigation entry for the test page. In Servo right now it just shows the navigation entry.
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I'm going to put my proposal for how to move forward in #41666 so it doesn't get lost here.
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🤖 Opened new upstream WPT pull request (web-platform-tests/wpt#57468) with upstreamable changes. |
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📝 Transplanted new upstreamable changes to existing upstream WPT pull request (web-platform-tests/wpt#57468). |
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📝 Transplanted new upstreamable changes to existing upstream WPT pull request (web-platform-tests/wpt#57468). |
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🔨 Triggering try run (#21601045563) for Linux (WPT) |
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Test results for linux-wpt from try job (#21601045563): Flaky unexpected result (24)
Stable unexpected results that are known to be intermittent (26)
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✍ Updated existing upstream WPT pull request (web-platform-tests/wpt#57468) title and body. |
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✍ Updated existing upstream WPT pull request (web-platform-tests/wpt#57468) title and body. |
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Excellent, that's a lot of tests that now run which previously didn't get a chance to run because we never recorded the resource timing entry. We can file followups for fixing the actual timing data and implementing the Timing Allow Origin check correctly. |
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You can use |
Signed-off-by: Osoro Bironga <[email protected]>
… subit_timing Signed-off-by: Osoro Bironga <[email protected]>
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I'll look out for these |
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📝 Transplanted new upstreamable changes to existing upstream WPT pull request (web-platform-tests/wpt#57468). |
Signed-off-by: Osoro Bironga <[email protected]>
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📝 Transplanted new upstreamable changes to existing upstream WPT pull request (web-platform-tests/wpt#57468). |
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Looking good! I've got a few small changes, but it's nice to see this working.
tests/wpt/tests/performance-timeline/timing-entries-iframe.html
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| // submit_timing will only accept timing that is of type ResourceTimingType::Resource | ||
| let mut resource_timing = timing.clone(); | ||
| resource_timing.timing_type = ResourceTimingType::Resource; |
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Mmmm, interesting. More evidence that some cleanup is needed in how these pieces are integrated in Servo.
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Added resource timing that was missing for an iframe document.
Testing: Added
Fixes: #41666