[webkit-dev] Request for position on Event Timing

[Ryosuke Niwa]

On Fri, Aug 7, 2020 at 2:09 PM Rob Buis <rbuis at igalia.com> wrote:
>
> I was not aware of Long Tasks API. However it seems to have a slightly
> different focus (task vs. input events). Also I am mostly interested in
> First Input Delay, and it was decided some time ago to not put it in
> Long Tasks API (see
> https://docs.google.com/document/d/1bYMLTkjcyOZR5Jt3vrulzMSoS32zOFtwyH33f6hW_C8/edit#).

The concern still withstands. We don't have dozens of slightly
different APIs that websites need to track for junks & delays during
user interactions.

It's also unclear how this first input delay works with a single page
app which may have multiple transitions after a single page load from
the browser engine's perspective. There had been some discussions
about this in the past in Web Perf WG but I don't think we've come to
any conclusion about it.

In general, I'm hesitant to have any of these APIs implemented in
WebKit without figuring out more coherent picture of how they'd all
fit together to address underlying use cases.

- R. Niwa

> On 06.08.20 20:07, Simon Fraser wrote:
> > Our feedback is that this API seems reasonable, but that there's overlap with the "long tasks" API,
> > and it's not clear if we need both.
> >
> > Simon
> >
> >> On Aug 6, 2020, at 10:43 AM, Rob Buis <rbuis at igalia.com> wrote:
> >>
> >> Hi Webkit-Dev,
> >>
> >> I would like to get an official position from Webkit on the Event Timing Web Perf API.
> >> Besides providing information about input event latency it can be used to obtain
> >> First Input Timing metrics. This specification builds on the Performance Timeline
> >> specification, which is implemented in Webkit. Chrome has implemented the Event
> >> Timing API, see the chrome status entry below.
> >>
> >> - Specification: https://wicg.github.io/event-timing/
> >> - Explainer: https://github.com/WICG/event-timing
> >> - MDN: https://developer.mozilla.org/en-US/docs/Web/API/PerformanceEventTiming
> >> - ChromeStatus: https://chromestatus.com/feature/5167290693713920
> >> - Caniuse.com URL: https://caniuse.com/#feat=mdn-api_performanceeventtiming
> >>
> >> Regards,
> >>
> >> Rob.
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