On 24/10/2013, at 17:06, François REMY wrote: > HTTP 2.0 can send you multiple files in parallel on the same connection: that > way you don't pay (1) the TCP's Slow Start cost, (2) the HTTPS handshake and > (3) the cookie/useragent/... headers cost.
Doesn't connection:keep-alive deal with (1) and (2) nicely? > Under HTTP 2.0, you can also ask for the next files while you receive the > current one (or send them by batch), and that reduces the RTT cost to 0. Http2.0 doesn't (and can't) fix the 1 RTT per request cost: it's just like http1.1. If http2.0 lets me ask for n files in a single request then yes, the RTT would be ˜ 1, or 1/n per request if you will, which is just like asking for a .zip in http1.1 > Also, the server can decide to send you a list of files you didn't request (à > la ZIP), making totally unnecessary for your site to ask for the files to > preload them. Can a server always know what the page is going to need next... beforehand? Easily? > The priority of downloads is negotiated between the browser and the server, > and not dependent on the 6 connections and the client. Yes, that sounds great! > The big advantage of the HTTP2 solution over the ZIP is that your site could > already load with only the most important files downloaded while if you use a > ZIP you've to wait until all files have been downloaded. 1.- Bundle *wisely* 2.- n gzipped files multiplexed in a single http2.0 connection don't necessarily arrive faster than the same files .zipped through a non-multiplexed http1.1 connection: multiplexing has an overhead (at both ends) that http1.1 hasn't. 3.- Yes, you can't (you can, but shouldn't until you've got the index which comes last) unzip a .zip as it arrives, but knowing for sure that all its files are cached (after unzipping) is a plus, imo. 4.- It's not http2.0 *or* .zip bundling. We could have both. Why not? > From a performance point of view, this is an issue. Also, since you can only > start analyzing the resources at that time, you will overload the CPU at that > time. If you can unzip the files one by one, you can spread the load over a > much longer time. Overload the cpu? :-P > ± In the equation you paint above something important is missing: the fact > that > ± there's a round-trip delay per request (even with http2.0), and that the > only > ± way to avoid it is to bundle things, as in .zip bundling, to minimize the > ± (number of requests and thus the) impact of latencies. > > Go find some HTTP2 presentation, you'll learn things ;-) Look, I've done it, I♥it, it's awesome, and I keep thinking that .zip bundling would be a nice thing to have too. -- ( Jorge )(); _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
