We now have our QA person (Rummana) testing on an iPad, which is helping to surface issues in general, but her focus has mostly been on bugs. We do have some scheduled bandwidth to deal with these problems, and now that we have a sort of deadline, I think it's a good idea to get some focus on this. I have a personal iPad, but prying it out of my wife's hands is tough. Do we have any more devices we can use at work for testing?
- Trevor On Thu, May 15, 2014 at 10:22 AM, Arthur Richards <[email protected]>wrote: > Trevor and VE folks more broadly, is this something you have now scheduled > to work on? We're currently planning to have VE for tablets in stable and > launch the automatic mobile redirect for tablets on June 17, and I'm > curious about the likelihood of tackling the performance issues from the VE > side of things before then. > > > On Thu, May 1, 2014 at 3:53 PM, Trevor Parscal <[email protected]>wrote: > >> The issues on load I believe we are having have to do with "shields". >> >> Shields are transparent 1x1 gif images we inject into the DOM to simulate >> selecting over objects which are made up of complex HTML structures. They >> originally also protected the HTML structure from being clicked on directly >> (hence the name "shield"). More recently other techniques such as >> "phantoms", "highlights" and "relocatable markers" have taken over the >> click blocking functionality. This technique was invented by Inez/Christian >> of Wikia, and is regarded as creative and effective but inefficient. >> >> Without doing much profiling, here is my best guess about what is going >> on. >> >> First we traverse DOM structures, looking for elements which might be >> able to display outside their parent's bounding box, such as position: >> absolute, or floats. This can be quite expensive because we have to do a >> lot of CSS computed style checks and measurements, and the code isn't fully >> optimized to use direct DOM methods so there's a little jQuery overhead. >> Second we then insert the transparent images into the DOM structures, and >> there could be hundreds of these pretty easily. >> >> Trying to solve this problem we can optimize the first step a bit. >> However, the traversal and measurement stuff will hit a limit pretty >> quickly. The technique we use to fake the selection may have alternative >> solutions, but I'm not sure about their performance impacts, especially on >> mobile devices. >> >> Overall, the shield/phantom/highlight/marker systems need to converge >> into a simpler and more performant solution, and I have a few general ideas >> and the intention to do this, but haven't yet sized it up or scheduled it. >> I'm hoping we can surface this as a more pressing issue now that mobile VE >> is hitting this wall, and get going on it soon. >> >> - Trevor >> >> >> On Thu, May 1, 2014 at 12:15 PM, Jon Robson <[email protected]>wrote: >> >>> I was tasked with investigating why on large pages, mobile takes >>> longer to load a page then VE. >>> To do this I loaded a template heavy page in both mobile and desktop >>> and ran JavaScript profiling on both. >>> >>> >>> In desktop7.9% of time was spent in jQuery.extend.css - this was the >>> most heavy function. In mobile it was also the most heavy - however in >>> mobile a whopping 23.76% of time was spent in jQuery.extend.css >>> >>> In mobile 14360 calls were made to by both desktop and mobile to get >>> the value of float. >>> >>> Looking closer at what was calling these I found it was related to >>> phantom element. >>> >>> So it looks like fixing the following bug: >>> https://bugzilla.wikimedia.org/show_bug.cgi?id=64709 >>> will help improve performance in mobile drastically. >>> >>> I imagine the slowdown is related to the fact that on desktop existing >>> content is replaced with VisualEditor interface but on mobile there >>> are more DOM elements as VisualEditor is opened in an overlay on top >>> of the content. >>> >>> Specifically the calls inside this callback that hog the most are: >>> 1) $this.css( 'float' ); >>> 2) node.$.context.importNode( $shieldTemplate[0], true ) >>> >> >> >> _______________________________________________ >> Mobile-l mailing list >> [email protected] >> https://lists.wikimedia.org/mailman/listinfo/mobile-l >> >> > > > -- > Arthur Richards > Software Engineer, Mobile > [[User:Awjrichards]] > IRC: awjr > +1-415-839-6885 x6687 >
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