[akalin]

Re. multiplexing at the HTTP layer, because an HTTP replacement has to be deployable and testable. However, now that the ideas in SPDY have been proven and are on their way to being standardized, you can look at QUIC to see what can be done when not limited to TCP and HTTP.

By overhead I mean latency overhead -- running a program to download a site to a local file and then displaying it in a browser will almost certainly have a higher time to start render. Not to mention you're hitting everything cold (i.e., not using the browser's cache).

[osth]

I don't measure latency as including rendering time. Maybe I'm not "rendering" anything except pure html.

I measure HTTP latency as the time it takes to retrive the resources.

Whatever happens after that is up to the user. Maybe she wants to just read plain text (think text-only Google cache). Maybe she wants to view images. Maybe she wants to view video. Maybe she only wants resources from one host. Maybe she does not want resources from ad servers. We just do not know. Today's webpages are so often collections of resources from a variety of hosts. We can't presume that the user will be interested in each and every resource.

Of course those doing web development like to make lots of presumptions about how users will view a webpage. Still, these developers must tolerate that the speed of users' connections vary, the computers they use vary, and the browsers they use vary, and some routinely violate "standards". Heck, some users might even clear their browser cache now and again.

But HTTP is not web development. It's just a way to request and submit resources. Nothing more, and nothing less.