*Contact emails*
mjack...@microsoft.com *Explainer* https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/PerformanceNavigationTiming%20for%20User%20Agent%20Launch/explainer.md <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FMicrosoftEdge%2FMSEdgeExplainers%2Fblob%2Fmain%2FPerformanceNavigationTiming%2520for%2520User%2520Agent%2520Launch%2Fexplainer.md&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803697942336%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=l545yNmj1lynC9I%2BDSYM0WwxIf%2B7JPscZVRwqyO0CG0%3D&reserved=0> *Specification* https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/PerformanceNavigationTiming%20for%20User%20Agent%20Launch/explainer.md <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FMicrosoftEdge%2FMSEdgeExplainers%2Fblob%2Fmain%2FPerformanceNavigationTiming%2520for%2520User%2520Agent%2520Launch%2Fexplainer.md&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803697949544%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=53CDOgKaQqUr7h0uuqV0XTreC9Xc4PjJCd4P8pfjcsg%3D&reserved=0> *Design docs* https://docs.google.com/document/d/1D6DqptsCEd3wPRsZ0q1iwVBAXXmhxZuLV-KKFI0ptCg/edit#heading=h.7nki9mck5t64 <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.google.com%2Fdocument%2Fd%2F1D6DqptsCEd3wPRsZ0q1iwVBAXXmhxZuLV-KKFI0ptCg%2Fedit%23heading%3Dh.7nki9mck5t64&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803697955783%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=I62vI9C34jU3P5nXvbD60nsR%2BMdmqbWoci8YcLZUX%2Fc%3D&reserved=0> *Summary* Web applications may suffer from bimodal distribution in page load performance, due to factors outside of the web application’s control. For example: * When a user agent first launches (a "cold start" scenario), it must perform many expensive initialization tasks that compete for resources on the system. * Browser extensions can affect the performance of a website. For instance, some extensions run additional code on every page you visit, which can increase CPU usage and result in slower response times. * When a machine is busy performing intensive tasks, it can lead to slower loading of web pages. In these scenarios, content the web app attempts to load will be in competition with other work happening on the system. This makes it difficult to detect if performance issues exist within web applications themselves, or because of external factors. Teams we have worked with have been surprised at the difference between real-world dashboard metrics and what they observe in page profiling tools. Without more information, it is challenging for developers to understand if (and when) their applications may be misbehaving or are simply being loaded in a contended period. A new ‘confidence’ field on the PerformanceNavigationTiming object will enable developers to discern if the navigation timings are representative for their web application. For this experiment, we are only supporting the "cold start" scenario described above. *Blink component* Blink>PerformanceAPIs>NavigationTiming <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fissues.chromium.org%2Fissues%3Fq%3Dcustomfield1222907%3A%2522Blink%253EPerformanceAPIs%253ENavigationTiming%2522&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803697962141%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=WdtB1JHzsqw7nptXBxD8q1M49xTT3TPMS5cXNoB6CIE%3D&reserved=0> *TAG review* https://github.com/w3ctag/design-reviews/issues/878 <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fw3ctag%2Fdesign-reviews%2Fissues%2F878&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803697968285%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=nM5HjM1NBtOLdJjcsSC8ztVxC2j7XQ2Q%2FRoQqUhbv2Y%3D&reserved=0> *TAG review status* Pending *Risks* *Interoperability and Compatibility* None. *Gecko*: No signal ( https://github.com/mozilla/standards-positions/issues/1191 <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fmozilla%2Fstandards-positions%2Fissues%2F1191&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803697974689%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=BjW9lcveF2md4KwSBMdMattz93S%2BiL6dCTOuqImJedA%3D&reserved=0> ) *WebKit*: No signal ( https://github.com/WebKit/standards-positions/issues/469 <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FWebKit%2Fstandards-positions%2Fissues%2F469&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803697981005%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=igAq%2B%2Fm4F9UA131uMaZJCquItGmJdDdFSZ6xasXf%2BVE%3D&reserved=0> ) *Web developers*: No signals *Other signals*: *WebView application risks* *Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?* *None* *Goals for experimentation* The noise added means that the 'confidence' field isn’t immediately useful to developers. Developers can collect this field in their Real User Monitoring (RUM) data and with enough records, correct the data to "eliminate the noise". One of the objectives of the experiment is to confirm developers are successfully able to do that. We're also interested in feedback about the API shape and ease of use. *Ongoing technical constraints* *Debuggability* *Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?* Yes *Is this feature fully tested by web-platform-tests <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fchromium.googlesource.com%2Fchromium%2Fsrc%2F%2B%2Fmain%2Fdocs%2Ftesting%2Fweb_platform_tests.md&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803697987015%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=4tQ8p8wUbdNcbU1w9Q2ycphr9%2B26QTFSFi%2FkaFN976U%3D&reserved=0>?* Yes third_party/blink/web_tests/http/tests/misc/performance-navigation-timing-entry-confidence.tentative.html *Flag name on about://flags* *Finch feature name* PerformanceNavigationTimingConfidence *Requires code in //chrome?* True *Tracking bug* https://bugs.chromium.org/p/chromium/issues/detail?id=1413848 <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugs.chromium.org%2Fp%2Fchromium%2Fissues%2Fdetail%3Fid%3D1413848&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803697993345%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=shu8uGiF7pcS6ba5a0wPZMQlhDqSP%2FFt1c%2Fkgo%2Fmr%2B8%3D&reserved=0> *Estimated milestones* Origin trial desktop first 136 Origin trial desktop last 139 DevTrial on desktop 135 Origin trial Android first 136 Origin trial Android last 139 DevTrial on Android 135 *Link to entry on the Chrome Platform Status* https://chromestatus.com/feature/5186950448283648?gate=5434970730921984 <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fchromestatus.com%2Ffeature%2F5186950448283648%3Fgate%3D5434970730921984&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803697999701%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=FDqM0V2hX1IyOGPQqIywtNc1KKRudAbaF7N7%2F0h5DRw%3D&reserved=0> *Links to previous Intent discussions* Intent to Prototype: https://groups.google.com/a/chromium.org/g/blink-dev/c/o0F7nBKsgg0/m/bJSp3ekfAAAJ <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.google.com%2Fa%2Fchromium.org%2Fd%2Fmsgid%2Fblink-dev%2FDM6PR00MB0751A324F65AAAAD9544C2028ED09%2540DM6PR00MB0751.namprd00.prod.outlook.com&data=05%7C02%7Cmjackson%40microsoft.com%7Cdc397aa61b7843369f3908dd5dc08796%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638769803698006323%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=aGxLAd3gKXHZFerHWRwS741opPk5%2BhEk8H6AyBok%2BRs%3D&reserved=0> -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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