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The Hidden Cost of Web Components - ATL Web Performance Meetup
Eliminating slow or unnecessary HTTP requests is essential to maintaining fast websites. Identifying which requests should be removed, however, can prove difficult. In this session, we'll present a new way of analyzing HAR data that ranks the various components of a website by the cost they have on performance.
Eliminating slow or unnecessary HTTP requests is essential to maintaining fast websites. Identifying which requests should be removed, however, can prove difficult. In this session, we'll present a new way of analyzing HAR data that ranks the various components of a website by the cost they have on performance.
13.
tracking down the source
“...an HTTP header field that identifies the address of the web page that
linked to the resource being requested.”
http://en.wikipedia.org/wiki/HTTP_referer
14.
tracking down the source
Referer Request Count Total Load Time (ms)
homepage (www.cnn.com) 177 34,433
z.cdn.turner.com/xslo/cvp/assets/contain
er/2.0.4.0/cvp_main_container...
44 7,214
ads.cnn.com/html.ng/site=cnn&cnn_page
type=main&cnn_position=728x90...
9 2,977
z.cdn.turner.com/cnn/tmpl_asset/static/w
ww_homepage/2970/css/hplib-min.css
22 2,348
ds.serving-sys.com/BurstingRes//Site-
40150/Type-2/ed3d7348-93fb-4938-8d...
2 2,308
17.
when to use what
Waterfall Chart Domain Analysis Referer Analysis
Visually represents a single
page load
Useful for:
● Identifying parser /
render-blocking
assets
● Spotting opportunities
for domain sharding
Aggregates resource load
times by domain
Useful for:
● Finding slow hosts
● Monitoring third-party
providers
Aggregates resource load
times by HTTP Referer
Useful for:
● Assigning costs to
resources
● Tracking down the
source for particular
requests
in the beginning there was the waterfall. helps identify render blocking stylesheets parser blocking scripts opportunities for domain sharding (lots of blocking) slow individual requests
use the referer to see the source of every request -- who is responsible for loading this resource?