Bug 37924 – Web Inspector: slow scroll speed of Timeline in case of many timeline marks

• Component: Web Inspector (Deprecated)
• Status: RESOLVED FIXED

[Ilya Tikhonovsky]

if we have significant amount of timeline marks then we have significant scrolling speed degradation. (2k marks)

[Ilya Tikhonovsky]

Created attachment 53959 [details]
[patch] initial version.

[Pavel Feldman]

Comment on attachment 53959 [details]
[patch] initial version.

Note that this does not address gmail's slowness. There are 1800 marks generated upon initial gmail load, i.e. we create 1800 elements. This obviously will not scale no matter what we do to scrolling. I was thinking of fixing it by introducing a canvas element instead of separate divs per record. Feel free to land your patch, but I don't think we should close the bug yet.

[Eric Seidel (no email)]

Attachment 53959 [details] was posted by a committer and has review+, assigning to Ilya Tikhonovsky for commit.

[Ilya Tikhonovsky]

(In reply to comment #2)
> (From update of attachment 53959 [details])
> Note that this does not address gmail's slowness. There are 1800 marks
> generated upon initial gmail load, i.e. we create 1800 elements. This obviously
> will not scale no matter what we do to scrolling. I was thinking of fixing it
> by introducing a canvas element instead of separate divs per record. Feel free
> to land your patch, but I don't think we should close the bug yet.

Everything was ok but when I created 2k marks by markTimeline I got scrolling speed slowed down as you described. The reason of that was the fact that each of these marks had additional DOM elements in timeline pane grid and timeline overview grid. 

As result for that use case we have not more then 100 visible rows in timeline panel and 2k x 2 additional  DOM elements recreated and reattached for the each scroll event. 

I've checked this use case by 10k events and now the scrolling speed is fine.

[WebKit Commit Bot]

Comment on attachment 53959 [details]
[patch] initial version.

Clearing flags on attachment: 53959

Committed r58087: <http://trac.webkit.org/changeset/58087>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.