I recommend watching this video by Fast.ly on some real metrics comparing HTTP/2 and HTTP/1:
https://www.youtube.com/watch?v=0yzJAKknE_k
Overall, the performance gain is not as much (if any) compared to the hype we hear.
https://www.youtube.com/watch?v=0yzJAKknE_k
Overall, the performance gain is not as much (if any) compared to the hype we hear.
There's a few challenges here…
WebPageTest uses DummyNet to simulate packet loss and in a HTTP/1.x scenario the not all TCP connections in the test will experience packet loss, whereas all the HTTP/2 ones will. Now in the real world if there's packet loss on route how likey is it that TCP connections experience packet loss?
Our H2 implementations are still young, this Cloudflare work is one example, until they made this patch nginx didn't support HPACK and there are other issues in other browsers and servers too.
As the implementations mature and we understand how to make the most of H2 then performance gains will appear - there's already evidence from people like the FT that there are gains to be made now.
Real world experience beats synthetic tests. Shipping counts for a lot.
In the time that some other competitors have been talking about HTTP/2 we've had it out for a year and have been experimenting and improving (server push, HPACK, ...). Clearly, HTTP/2 is not the one-size-fits-all-answer-to-everything, but it amuses me to see competitors not shipping, yet talking a good game. See this sort of thing with HTTP/2, IPv6, ...
"Look at how much faster HTTP/2 is loading this page that is nothing but an array of 64 x 64 icons that are each 16x16 pixels!" -- well of course that's going to be slow with HTTP/1 if each icon is unique and not cached. But who does that? If that pathological case is yours, then sprite the icons and now it's one request, done.