Google's speed guru, Ilya Grigorik, announced on Google+ that they've made Google mobile search a bit faster, between 100-150 milliseconds faster to be exact. That is about 0.15 seconds faster than yesterday.
How did Google do this? They are using a technique named reactive prefetch. Reactive prefetch, which Ilya explains as:
The key insight is that we are not speculatively prefetching resources and do not incur unnecessary downloads. Instead, we wait for the user to click the link and tell us exactly where they are headed, and once we know that, we tell the browser which other resources it should fetch in parallel.
Note, this only speeds things up on Google Chrome on Android, since it is the only browser live that supports reactive prefetch. Ilya goes on to explain more of the tech behind this:
As you can infer, implementing the above strategy requires a lot of smarts both in the browser and within the search engine... First, we need to know the list of critical resources that may delay rendering of the destination page for every page on the web! No small feat, but the Search team has us covered - they're good like that. Next, we need a browser API that allows us to invoke the prefetch logic when the click occurs: the search page listens for the click event, and once invoked, dynamically inserts prefetch hints into the search results page. Finally, this is where Chrome comes in: as the search results page is unloaded, the browser begins fetching the hinted resources in parallel with the request for the destination page. The net result is that the critical resources are fetched much sooner, allowing the browser to render the destination page 100-150 milliseconds earlier.
Forum discussion at Google+.
