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Base module request loads after images on Japanese Wikipedia
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Description

In these two examples JavaScript starts loading only after the images have been downloaded and rendered. This equates to a delay of around 8s on emulated 2G mobile.

http://wpt.wmftest.org/result/160328_JR_7E/1/details/
http://wpt.wmftest.org/result/160328_WE_CS/1/details/

This doesn't seem to happen on English Wikipedia:
http://wpt.wmftest.org/result/160328_EM_93/1/details/

I'm not sure if there is an issue here but seemed worth investigating.

Event Timeline

Krinkle renamed this task from Startup module loading only after images downloaded on Japanese Wiki to Base module request loads after images on Japanese Wikipedia.Apr 11 2016, 6:35 PM
Krinkle updated the task description. (Show Details)

@Peter any thoughts about this? Will your recent changes help this in any way?

I think T123582 will be thing for slow connections so we can start do the lookup for upload earlier and then start downloading the first image earlier.

Peter moved this task from Inbox to Next: Goal / Jul-Sep '21 on the Performance-Team board.

Let me re-test this again.

We have changed a lot since this happened the first time (H2 and lazy loading of images). Running on Japanese wiki looks like this now:

Screen Shot 2016-12-20 at 3.54.02 PM.png (1×1 px, 383 KB)

https://www.webpagetest.org/result/161220_RD_674f1db70a85495f65c9843f856a1b1a/1/details/#waterfall_view_step1

And English:

Screen Shot 2016-12-20 at 3.55.17 PM.png (776×1 px, 278 KB)

https://www.webpagetest.org/result/161220_GF_0d40b6b805a168d70d71b35fe2003cca/2/details/#waterfall_view_step1

Chrome in this case alway prio the Javascript to start first (same "low" prio as the images). The dns/connect/ssl starts late so T123582 would hopefully make it better. See how <link rel="dns-prefetch" href="//login.wikimedia.org"/> make the dns happen earlier for login!