1383538 - lightningmaps.org very slow, makes the content process unresponsive

Status: RESOLVED INCOMPLETE

(Core :: JavaScript Engine, defect, P3)

Description

[6lobe]

URL: https://www.lightningmaps.org

Very slow performance compared to Chrome, especially when you enable additional map features from the top right corner.

Furthermore, if I leave the site open for a while and then navigate away from it (in the same tab/content process) the performance remains poor and the tab keeps going unresponsive from time to time. Mouse input is especially affected.

I need to kill the tab/content process as it is unusable even after navigating away from this site.

CPU usage remains at 100% too for some time even after leaving the site.

Comment 1

[6lobe]

I am also hitting some crashes on this site.

Comment 2

[Abe - QA (:Abe_LV)]

Hi reporter(6lobe),

I have tested this on Ubuntu 16.04 with latest nightly, but I could not manage to reproduce.
Could you please provide the performance report? The steps are described in detail here: https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Reporting_a_Performance_Problem

thanks

Comment 3

[6lobe]

Here is a performance report:

https://perfht.ml/2vmkCtV

Comment 4

[Abe - QA (:Abe_LV)]

Hi Mike,
Comment/suggestion on this performance report, comment 3? Thanks

Comment 5

[Mike Conley (:mconley) (:⚙️)]

Two things jump out at me:

1) There's a long series of paints occurring in a row, purportedly blocking the main thread throughout. This looks like it's probably some kind of animation running on the main thread, but it's hard to say for sure. JS is firing throughout the animation, but it doesn't look like it's running the animation directly, just adding data from a message event... : https://perfht.ml/2vLVihC

2) There's a bunch of stuff near the beginning that looks like raw JS being run. The JS team might be interested in looking at that: https://perfht.ml/2vMekVe

I'm afraid that's all I see.

Comment 6

[Abe - QA (:Abe_LV)]

Moving it to JS Engine component based on comment 5.

Comment 7

[Naveed Ihsanullah [:naveed]]

Worth retrying in FF57+. I tried it and it feels snappy on both Chrome and FF57beta.