| Jdlrobson | |
| Mar 28 2016, 11:04 PM |
| F5110042: Screen Shot 2016-12-20 at 3.54.02 PM.png | |
| Dec 20 2016, 3:02 PM |
| F5110047: Screen Shot 2016-12-20 at 3.55.17 PM.png | |
| Dec 20 2016, 3:02 PM |
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.
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.
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:
And English:
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!