Undersatnding how and when previously cached files may be processed.

Web Performance Discuss Test Results
1

Hi there,

Our speed focus is predominantly on how our logged-in members interact with a site. By definition these users will have been to at least one other page on the site and so a fair proportion of the page assets and static content will have already been cached locally.

The view we have traditionally used on WPT is the filmstrip, to get a visual feel for when the page looks ready for use. In this example below this is 1.6 seconds in:

http://www.webpagetest.org/video/compare.php?tests=120919_8J_B6H-r%3A8-c%3A0&thumbSize=200&ival=100&end=visual

It looks like the waterfall only focuses on those files that require download. Is there a view that shows us how and when the Browser might be processing previously downloaded files?

As you can see there are some gaps in our waterfall, eg between items 4 and 5. So we’re wondering could this be when the Browser is dealing with local files? Or is this hypothesis incorrect and we should still be looking to close the gaps…

As always, all advice gratefully received…

Thanks,

Pete.

2

If you use Chrome you can capture a dev tools timeline trace which should give you more visibility into the gaps.

3

Thanks Pat. We’ll check this out!