New issue
Advanced search Search tips
Note: Color blocks (like or ) mean that a user may not be available. Tooltip shows the reason.

Issue 681863 link

Starred by 3 users

Issue metadata

Status: Assigned
Owner:
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 3
Type: Feature



Sign in to add a comment

Surface Long Tasks in DevTools

Project Member Reported by panicker@chromium.org, Jan 17 2017

Issue description

For diagnosis, it would be great if developers could directly get a view of long tasks (surfaced from the API) in DevTools.
Currently this surfaces with FPS / slow frame red warning and script / layout etc breakdown
This is fine, but directly indicating long tasks would be a good addition and unify / strengthen our message of Long Tasks as perpetrators of responsiveness issues.
Thoughts?

Record a profile on this demo to get an idea:
https://wicg.github.io/longtasks/render-jank-demo.html
 

Comment 1 by caseq@chromium.org, Jan 17 2017

Owner: caseq@chromium.org
Status: Assigned (was: Untriaged)
Components: Platform>DevTools>Performance
Andrey, any thoughts on whether devtools would consider exposing this?
Cc: dproy@chromium.org
I'll bring this up at the next Chrome Speed Metrics meeting.
Current proposal: 
Add a separate track (like above frames) that is "Tasks" or "Long Tasks". In it we place new boxes for long tasks. They represent scheduler-level tasks (ThreadControllerImpl::DoWork). We probably only show ones that are long (>50ms) and maybe add more red color as their duration increases.
Labels: -Type-Bug Type-Feature
Status: WontFix (was: Assigned)
DevTools is presenting long tasks already in the form of:
- console log violations and
- warning markers on the performance timeline
Owner: ----
Status: Untriaged (was: WontFix)
I believe the warning markers on the performance timeline use a different definition of task than Chrome's scheduler, which means that you can block the main thread for long periods of time without getting warnings.

Is this not the case?
That's true. the precise definition of long tasks used in scheduler/longtasksapi is not conveyed in the timeline.
Owner: binghamj@chromium.org
Status: Assigned (was: Untriaged)

Sign in to add a comment