Web Performance - Case for HTTP/2 with Andy Davies

Summary

Interesting meetup : http://www.meetup.com/Dutch-Web-Operations-Meetup/events/224787669/

Not really me area of experteasse but still intersting.

Andy Davies covered many of the topics in 

Software Engineering Radio Episode 232: Mark Nottingham on HTTP/2
http://www.se-radio.net/2015/07/episode-232-mark-nottingham-on-http2/ 


Notes

Web Performance - Case for HTTP/2 with Andy Davies

@AndyDavies

AWS

1999 RFC2126 HTTP/1.1

HTTP/1.x doesn't use the network efficiently

- good for transfering large files

- but most webpages are made up of lots of small sessiom

- each TCP connection only supports one request at a time

- HTTP Pipeline

- splitting resources over mulitiple hosts (e.g. bbc.co.uk)

- headers sent on every request ... Mark Nottingham found huge duplication of content (200K of cookies with every page load .. big UK online retailer)

- reduce requests ... CSS and JavaScripts bundles,

      image sprites : browser has to decode whole image (expensive on smaller mobiles)

- use gulp or grunt to automate working around limitations for http/1.x

- test with image of little sqaure iimages ... skewed to show http2 strenght

- header frame and data frames

- insanely complex 'prioritse weights and dependencies'

- headers deduplicates into a dictionary

- long latency test (ireland-singapore) http 2 wins ...

- but only benefit for low latency test is security (over tls)

- what happens if you have packet loss (over a session on a single connection)

- server push ... currently we have "network idle" time while the "server builds page"

  - now push critical css

 John Mellor (Google)

 - parallel image loading looks good after 15% and very good at 25%

 - do people dislike partial imaging loading (needs bigger study)

 Good browser support for http2

 - especially firefox and chrome

 Limited server for http2

 - h2o server

 - nginx should have something later this year

 - http2 killing off apache? nope http2 code is now being ported

 - haproxy doesn't support http2 yet

 Problems with SPDY

 - issues with priotisation rules not being

 h2spec

 - japanese buid tool for checking if the

 h2i

 - interactive consul for debug

 - tricky to use

 reducing sharding

 - two shard domains but usingn a single tcp connection

 3rd parties still growing

  - ab test

  - advertising

  - tag management

 w3c resource hints <link ref='...'>

 - dns-prefetch (all browsers already provide this)

 - preconnet (chrome only at the moment)

 - preload

 -  

 testing

 - chrome dev tools .. network testimh

 - webpagetest .. firefox identifies resources correctly (unlike chrome)

 f5, acmi, iss