4Time Spent on the Frontend Empty CachePrimed Cacheamazon.com82%86%aol.com94%cnn.com81%92%ebay.com98%google.com64%msn.com97%95%myspace.com96%wikipedia.org80%88%yahoo.comyoutube.com
5The Performance Golden Rule 80-90% of the end-user response time isspent on the frontend. Start there.Greater potential for improvementSimplerIf you could cut performance in half, FE changes would be 40-45%, while BE would be only 5-10%.BE changes are typically more complex: rearchitecture, optimize code, add/modify hw, distribute databases, etc.FE is simpler: change web server config, place scripts and stylesheets differently in the page, combine requests, etc.I’ve worked with dev teams to cut response times on 50 properties, often by 25% or more.Proven to work
714 Rules Make fewer HTTP requests Use a CDN Add an Expires header Gzip componentsPut stylesheets at the topPut scripts at the bottomAvoid CSS expressionsMake JS and CSS externalReduce DNS lookupsMinify JSAvoid redirectsRemove duplicate scriptsConfigure ETagsMake AJAX cacheablein priority orderaddressing these rules improve response times
8YSlowperformance lint toolgrades web pages for each rule
11Rule 3: Add an Expires header not just for imagesImagesStylesheetsScripts% with ExpiresMedian Ageamazon.com0/620/10/30%114 daysaol.com23/431/16/1848%217 dayscnn.com0/1380/22/111%227 daysebay.com16/200/755%140 daysfroogle.google.com1/234%454 daysmsn.com32/353/980%34 daysmyspace.com0/181 daywikipedia.org6/82/375%yahoo.com23/234/4100%n/ayoutube.com0/3226 daysImagesStylesheetsScripts% with ExpiresMedian Ageamazon.com0/620/10/30%114 daysaol.com23/431/16/1848%217 dayscnn.com0/1380/22/111%227 daysebay.com16/200/755%140 daysfroogle.google.com1/234%454 daysmsn.com32/353/980%34 daysmyspace.com0/181 daywikipedia.org6/82/375%yahoo.com23/234/4100%n/ayoutube.com0/3226 daysOne thought: you can't put an Expires header because the content is constantly changing.But when we look at the Last-Modified header we see that's not the case. For MySpace it is, but Amazon, CNN, Froogle and YouTube all have lengthier Last_modified values.
12Takeaways focus on the frontend it's time for F2Es to shine harvest the low-hanging fruitsmall investment up front keeps on givingyou do control user response timesLOFNO – be an advocate for your users