1520505 - Banner ad taking much longer to retrieve/render in Firefox than in Chrome

Status: RESOLVED INVALID

(Core :: Performance: Navigation, enhancement)

Description

[Andrew Creskey [:acreskey]]

When loading the following buzzfeed page we see that the banner ad appears in Firefox roughly 11 seconds after it does in Chrome.
Otherwise the page rendering is comparable (within a second) in each browser.

Site:
https://www.buzzfeed.com/daves4/the-new-york-times-makes-the-nerdiest-correction-e?utm_term=.tlL2KE08L6#.hwrBglaV2A

Filmstrip replay (comparing Firefox to Chrome on Moto G4)
https://www.webpagetest.org/video/compare.php?tests=190113_DA_9b8801efe5673acdd127a79ff812fcc4-r:1,190113_P2_5578faf79a7aa1617272123e889d550d

I've reproduced this scenario multiple times.
Sometimes different ads are served, however Chrome consistently renders them sooner.

On this particular page this delay affects the timing of the onLoadEvent.

Comment 1

[Andrew Creskey [:acreskey]]

I believe that the same problem can be seen here in the Nimbledroid results for that site:
https://health.graphics/android/graph?site=https://www.buzzfeed.com/daves4/the-new-york-times-makes-the-nerdiest-correction-e?utm_term=.tlL2KE08L6#.hwrBglaV2A

Comment 2

[Sean Feng [:sefeng]]

Tested the same website on my Moto G5. I am able to see a gap, however, it is not as big as 11 seconds we see on Webpagetest. Fennec/Geckoview_example takes ~11 seconds to load the ad whereas Chrome Beta takes ~8 seconds.

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

We need some profile here. Somehow we trigger the image load before load event and I think Chrome triggers it afterwards.

That page is using fetch(), which we don't de-prioritize during page load yet
(https://bugzilla.mozilla.org/show_bug.cgi?id=1538516).

Comment 4

[Andrew Creskey [:acreskey]]

needinfo myself to capture new profiles.

Comment 5

[Sean Feng [:sefeng]]

Profile http://bit.ly/2TCvtIt, the banner image loaded around 19 seconds

Comment 6

[Andrew Creskey [:acreskey]]

It's very possible that this is caused by Bug 1529044 which has been improved and we're working on improving further.

Comment 7

[Vicky Chin [:vchin]]

Can you see if this is still an issue?

Comment 8

[Andrew Creskey [:acreskey]]

When I load this site the banner ad no longer appears in either geckoview_example or Chrome (instead the page animates up).

Since this can no longer be reproduced I'll close this.