The hard part of perf work is not fixing the perf. The hard part of perf work is measuring the perf. - Sam Sacoone.

How to measure performance bottlenecks

There are a lot of tools that you can use to measure perf bottlenecks

• Dev Tools - Use the timeline feature of your devtools to measure performance bottlenecks.

• Webpagetest

• DareBoost

• YellowLab

• PageSpeedInsights

Read Perf Audits

• Sam Sacoone 's audit of m.imgur.com.

• Paul Irish's audit of reddit mobile website.

Watch Talks on Web Performance

• Jake Archibald's bt-conf berlin talk.

• SuperCharged is a show where Paul Lewis does small performance audit on peoples' sites and recommends some fixes.

• RAIL .

and a lot more.