1399965 - activity stream periodically pegs a content process

Status: RESOLVED FIXED

(Firefox :: New Tab Page, defect)

Description

[Andrew Swan [:aswan]]

Attachment: Firefox 2017-09-14 09.26 profile.sps.json.gz

I've attached a profile, the relevant part is content process #3 beginning about 7s into the profile.

Comment 1

[Andrew Swan [:aswan]]

Also, the Activity Stream version is: 2017.09.12.1376-781e5de5

Comment 2

[Ed Lee :Mardak]

k88hudson, any suggestions on how to debug?

A brief look at the inverted js call stack shows 44% running time (4.5sec) in _updateDOMProperties of resource://activity-stream/vendor/react-dom.js

aswan says it's version 2017.09.12.1376-781e5de5 which corresponds to
https://searchfox.org/mozilla-central/rev/6326724982c66aaeaf70bb7c7ee170f7a38ca226/browser/extensions/activity-stream/data/content/activity-stream.bundle.js

The call stack:
initStore https://searchfox.org/mozilla-central/rev/6326724982c66aaeaf70bb7c7ee170f7a38ca226/browser/extensions/activity-stream/data/content/activity-stream.bundle.js#3024
rehydrationMiddleware https://searchfox.org/mozilla-central/rev/6326724982c66aaeaf70bb7c7ee170f7a38ca226/browser/extensions/activity-stream/data/content/activity-stream.bundle.js#2977
messageMiddleware https://searchfox.org/mozilla-central/rev/6326724982c66aaeaf70bb7c7ee170f7a38ca226/browser/extensions/activity-stream/data/content/activity-stream.bundle.js#2970
redux

Comment 3

[Kate Hudson :k88hudson]

Hm, I wonder if the extra data URIs for highlights is what's causing this. We could take a look at profiling that specifically, maybe turn on the dev version of react locally if that doesn't turn anything up

Comment 4

[Kate Hudson :k88hudson]

After some investigation it looks like the Sections component's render function is being called 9 times on every load (since it is receiving 9 SECTION_UPDATE_CARD events), that's something we might want to look more into

Comment 5

[Ed Lee :Mardak]

Hopefully fixed by https://github.com/mozilla/activity-stream/pull/3480 to be uplifted via bug 1399970.

Comment 6

[Ed Lee :Mardak]

The current Nightly 57.0a1 (2017-09-15) (Built from https://hg.mozilla.org/mozilla-central/rev/893fe1549e1e7342a66514b65960f08d40810a34) should have a fix. Can you see if that improves things / avoids the jank?

Comment 7

[Andrew Swan [:aswan]]

(In reply to Ed Lee :Mardak from comment #6)
> The current Nightly 57.0a1 (2017-09-15) (Built from
> https://hg.mozilla.org/mozilla-central/rev/
> 893fe1549e1e7342a66514b65960f08d40810a34) should have a fix. Can you see if
> that improves things / avoids the jank?

I just re-enabled activity stream, I'll let you know if I see the same thing again.
I'm curious though, the lag this created for me made the browser nearly unusable, but it doesn't seem like this was reported by anybody else?  Could there be something specific about my profile that made this especially noticeable for me?