Did the experimentation show any positive or negative impact on real-life content?
On Thu, Feb 16, 2023 at 10:18 PM François Doray <[email protected]> wrote: > The change to the nesting level at which 4ms clamping kicks in > (MaxUnthrottledTimeoutNestingLevel) never shipped, because Speedometer 2.1 > is not affected by it like Speedometer 2.0 was. However, WebKit did > implement this change: > https://sourcegraph.com/github.com/WebKit/WebKit/-/commit/786e3e0b252e38fb01c8db97a94d52cb0f57891e > and Chrome updated its documentation: > https://github.com/GoogleChrome/developer.chrome.com/commit/b6529b1cc8fdd9b2cb3496f446ee332207ab40b2 > even though it did not ship the change. > > What do Blink owners recommend as next step for this? > Does the current spec match reality? (where this value is UA defined) If not, maybe that's the easiest way to provide clarity on this point, if WebKit is shipping one thing and Chromium does another. Also - where does Gecko stand on this? > On Wednesday, May 25, 2022 at 2:59:30 PM UTC-4 Etienne Pierre-doray wrote: > >> Hi all, >> >> I'm sharing an update with results of the experiments over 21 days on >> Chrome Beta M102. >> >> The results below are mostly small percentages changes, and the finch >> guidelines >> <https://groups.google.com/a/google.com/g/chrome-catan/c/ZL-FCrq-Q40/m/ntQk88UFBgAJ?utm_medium=email&utm_source=footer> >> says to trust results on Stable. Given no issue have been raised AFAIK >> I would like to roll out a 1% finch experiment on Stable and I'm wondering >> what would be the required steps to do this (besides flipping boxes on >> the launch crbug.com/1298967 <http://crbug.com/1298967>) without >> amending what the spec >> <https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html> >> says just yet. >> >> >> The experiment MaxUnthrottledTimeoutNestingLevel >> <https://docs.google.com/document/u/1/d/1boT0k8BQjl7mXXzvI9SdN4XJPSza27vE8T0CNxmMhCI/edit> >> has been running on canary/dev/beta M101 and M102. >> >> Another experiment SetTimeoutZeroWithoutClamping >> <http://crbug.com/1263190> which removes setTimeout(,0) clamping to 1 ms >> is running at Enabled(25%) and Default(50%) on Beta. Analyzing the results >> for both experiments together makes sense because our goal is to avoid >> delayed tasks for immediate setTimeout()s. >> >> MaxUnthrottledTimeoutNestingLevel (50% enabled / 50% control) + >> SetTimeoutZeroWithoutClamping (Default + Enabled is 75%) >> >> Finch Win >> <https://uma.googleplex.com/p/chrome/variations?sid=d5a6fc8df0a156c8cf12f5271ee633ac> >> , >> >> No impact on Guiding Metrics >> >> Finch Mac >> <https://uma.googleplex.com/p/chrome/variations?sid=4720de277607785af52a737fcf5dad82> >> >> -15.85% Time To Paint For Each Ad Frame @ 95%ile 2-diamonds >> >> Finch Android >> <https://uma.googleplex.com/p/chrome/variations?sid=61617c1a3a8be13ab86afd5efd47eac7> >> >> -1.78% First Input Delay @ 99%ile 1-diamonds >> >> -0.74% Time to Largest Contentful Paint @ 99%ile 1-diamonds >> >> -0.79% Cumulative Layout Shift @ 95%ile 2-diamonds >> >> -1.45 / 1.26% Startup Time @ 95 / 99%ile 1 / 2-diamonds >> >> +1.93% Scroll Latency Count 1-diamonds >> >> +0.32% Memory: Renderer@ 50%ile 1-diamonds >> >> MaxUnthrottledTimeoutNestingLevel ignoring SetTimeoutZeroWithoutClamping >> >> Note: Results here are less interesting since our goal is to avoid >> delayed tasks for immediate setTimeout()s, which is only achieved under >> SetTimeoutZeroWithoutClamping. >> >> Finch Win >> <https://uma.googleplex.com/p/chrome/variations?sid=a67092052bb30ce06b7d71914f174a68> >> >> +1.73% Time to First Contentful Paint @ 95%ile 2-diamonds >> >> -1.28% Frame Drawing Interval @ 95%ile 1-diamonds >> >> -1.44% Startup Time @ 99%ile 1-diamonds >> >> >> Note: the downside of experimenting on Stable is that the intersection of >> both 1% experiments is very small and we probably won't be able to analyze >> results alongside before SetTimeoutZeroWithoutClamping ships (this >> should happen soon though). >> >> >> Maybe a console warning message if we hit the nesting level that we plan >>> to increase? I'm not sure how effective that would be in helping get folks >>> to try it. >>> >> I'm trying this out here >> <https://chromium-review.googlesource.com/c/chromium/src/+/3668605>. >> >> >> On Wed, Mar 30, 2022 at 2:19 PM Scott Haseley <[email protected]> >> wrote: >> >>> On Wed, Mar 30, 2022 at 10:41 AM Etienne Pierre-doray < >>> [email protected]> wrote: >>> >>>> Thanks! >>>>> >>>>> What's the plan for finding sites this breaks? Monitor bug reports? Or >>>>> is there something more proactive we could do? >>>>> >>>> I'm thinking about bug reports and guardian metrics. shaseley@ might >>>> have additional insight from running a similar experiment >>>> crbug.com/1263190 >>>> >>> >>> Yeah that's what I was thinking; that's the approach we're taking for >>> removing setTimeout(0) 1 ms clamping. It would be helpful if devs could try >>> this out and report issues (it's enabled behind a flag >>> <https://groups.google.com/a/chromium.org/g/blink-dev/c/-TjeYs7shTQ/m/th-1ACvYDAAJ>). >>> Maybe a console warning message if we hit the nesting level that we plan to >>> increase? I'm not sure how effective that would be in helping get folks to >>> try it. >>> >>> On Wed, Mar 30, 2022 at 6:00 AM Yoav Weiss <[email protected]> wrote: >>>> >>>>> LGTM to experiment M101-102 inclusive >>>>> Thanks for working on this!! >>>>> What's the plan for finding sites this breaks? Monitor bug reports? Or >>>>> is there something more proactive we could do? >>>>> >>>>> On Monday, March 28, 2022 at 9:36:30 PM UTC+2 Etienne Pierre-doray >>>>> wrote: >>>>> >>>>>> Contact [email protected] >>>>>> >>>>>> ExplainerNone >>>>>> >>>>>> Specification >>>>>> https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html >>>>>> >>>>>> Design docs >>>>>> >>>>>> https://docs.google.com/document/d/1boT0k8BQjl7mXXzvI9SdN4XJPSza27vE8T0CNxmMhCI >>>>>> >>>>>> Summary >>>>>> >>>>>> Increase the nesting threshold before which setTimeout(..., <4ms) >>>>>> start being clamped, from 5 to 100. setTimeout(..., 0) is commonly used >>>>>> to >>>>>> break down long Javascript tasks and let other internal tasks run, which >>>>>> prevents the browser from hanging. setTimeouts and setIntervals with an >>>>>> interval < 4ms are not clamped as aggressively as they were before. This >>>>>> improves short horizon performance, but websites abusing the API will >>>>>> still >>>>>> eventually have their set setTimeouts clamped >>>>>> >>>>>> >>>>>> Blink componentBlink >>>>>> <https://bugs.chromium.org/p/chromium/issues/list?q=component:Blink> >>>>>> >>>>>> TAG review >>>>>> >>>>>> TAG review statusNot applicable >>>>>> >>>>>> Risks >>>>>> >>>>>> >>>>>> Interoperability and Compatibility >>>>>> >>>>>> setTimeout is a well established and mature API. This change poses a >>>>>> risk of breaking websites and tests that rely on the current timing >>>>>> caused >>>>>> by clamping and the subtle task ordering that it entails. As an example, >>>>>> this change breaks assumptions about the ordering between setTimeout(0) >>>>>> and >>>>>> unrelated tasks in at least one case in Chrome tests ( >>>>>> crbug.com/1302309). On the flip side, the implementation in Chrome >>>>>> is already non compliant (crbug.com/1108877). There's also a similar >>>>>> experiment on beta that is ongoing (crbug.com/1263190). Devs can use >>>>>> chrome://flags#unthrottled-nested-timeout to test their sites for >>>>>> compatibility issues. >>>>>> >>>>>> >>>>>> Gecko: No signal >>>>>> >>>>>> WebKit: No signal >>>>>> >>>>>> 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? >>>>>> >>>>>> >>>>>> >>>>>> Goals for experimentation >>>>>> >>>>>> Gain insight on potential compatibility issues and evaluate impact on >>>>>> guardian metrics (page load, latency). >>>>>> >>>>>> >>>>>> >>>>>> Ongoing technical constraints >>>>>> >>>>>> None >>>>>> >>>>>> >>>>>> Debuggability >>>>>> >>>>>> setTimeout() and setInterval() have an associated trace event in >>>>>> DevTools. >>>>>> https://developer.chrome.com/docs/devtools/evaluate-performance/performance-reference/ >>>>>> >>>>>> >>>>>> Will this feature be supported on all six Blink platforms (Windows, >>>>>> Mac, Linux, Chrome OS, Android, and Android WebView)?Yes >>>>>> >>>>>> Is this feature fully tested by web-platform-tests >>>>>> <https://chromium.googlesource.com/chromium/src/+/master/docs/testing/web_platform_tests.md> >>>>>> ?No >>>>>> >>>>>> Flag nameunthrottled-nested-timeout >>>>>> >>>>>> Requires code in //chrome?False >>>>>> >>>>>> Tracking bughttps://crbug.com/1108877 >>>>>> >>>>>> Estimated milestones >>>>>> OriginTrial desktop last 102 >>>>>> OriginTrial desktop first 101 >>>>>> DevTrial on desktop 101 >>>>>> OriginTrial android last 102 >>>>>> OriginTrial android first 101 >>>>>> DevTrial on android 101 >>>>>> >>>>>> Targeting Beta 50% for at least 8 weeks for more chance of teasing >>>>>> out breakage. I'll send a follow-up with what we learn prior to >>>>>> experimenting on Stable. >>>>>> >>>>>> Link to entry on the Chrome Platform Status >>>>>> https://chromestatus.com/feature/5710690097561600 >>>>>> >>>>>> Links to previous Intent discussionsReady for Trial: >>>>>> https://groups.google.com/a/chromium.org/g/blink-dev/c/-TjeYs7shTQ/m/FhJq0mQyDAAJ >>>>>> >>>>>> >>>>>> This intent message was generated by Chrome Platform Status >>>>>> <https://chromestatus.com/>. >>>>>> >>>>> -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAL5BFfV6%3DHOeg%3D1dFzmBeGKTtouSKX2xco5MLkZn7QKvng5HJw%40mail.gmail.com.
