807791 - canvas/jquery huge jank from http://ocspreport.x509labs.com/

Status: NEW

(Core :: Graphics: Canvas2D, defect)

Description

[Patrick McManus [:mcmanus]]

when data starts coming in from this "dashboard" oriented site (which takes a few seconds due to server side issues) firefox just janks itself to pieces for several seconds - basically becoming unusable.

chrome doesn't blink. ie has issues too.

See the profile http://people.mozilla.com/~bgirard/cleopatra/#report=cccb40c36cdefda12708b114d2295eeee6db7a8b

most of the time is in jquery with a fair chunk calling canvas rendering. I didn't know for sure where to file it.

Comment 1

[Patrick McManus [:mcmanus]]

long periods of time where avg responsiveness is 375ms

Comment 2

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

My guess is that it's Canvas.  Looking at it it seems to draw each canvas from the callback, and does all the drawing in one go.  I don't know how many points it has or how complex the drawing is, but I think a *huge* amount.  If you click on the "table" icon in one of those little widgets, it looks like it's drawing around 30093 samples per chart.  Each one seems to be a stroked path (likely to get the little white circle in the middle), and they're either doing it all as one path with lots of subpaths, or as individual paths per circle.

Regardless, it's going to be slow.  Chrome actually janks exactly as much as we do -- but only in that page, thanks to multiple processes.  (Click and hold anywhere in the page and move the mouse to select/unselect elements while it's loading -- you'll see the same behaviour.)

I don't think there's anything we can fix here -- the app is just written in a very slow janky way, and the app itself needs to be fixed.

Comment 3

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

(The drawing is all coming from flot, a jQuery plotting library... which is why you're seeing so much jQuery in there stack, too)

Comment 4

[Mike Taylor [:miketaylr]]

I'm guessing e10s helps us jank the same as Chrome here?

(The reported site is no longer available...)