Simon Willison’s Weblog

6 items tagged “webperformance”

The current homepage clocks in at 1.9MB of CSS (156KB compressed). After re-building a fully-functional version of the homepage with CSS Blocks, we were able to serve the same page with just 38KB of CSS. To be clear: that’s the uncompressed size. After compression, that CSS file weighed in at less than 9KB!

Chris Eppstein # 24th April 2018, 8:40 pm

The biggest bottleneck in web performance today is CPU. Compared to seven years ago, there’s 5x more JavaScript downloaded on the top 1000 websites over the last seven years, and 3x more CSS. Half of web activity comes from mobile devices with a smaller CPU and limited battery power.

Steve Souders # 18th January 2018, 2:39 pm

The Best Request Is No Request, Revisited · An A List Apart Article. In HTTP/2 the rules have changed: serving unnecessary code as part of a larger bundle to avoid extra request overhead no longer makes sense. Splitting your code into many files and loading just the ones needed by the current page can knock seconds off your load time. # 28th November 2017, 3:50 pm

Can You Afford It?: Real-world Web Performance Budgets. Alex Russell’s magnum opus on web performance budgets in 2017. He proposes a baseline testing device equivalent to a $200 Android phone on a slow 3G network emulated at 400ms RTT/400Kbps transfer and encourages a goal of 5s time-to-interactive on first load and 2s TTI for subsequent views. This means around 130kb of gzipped JavaScript—challenging but not impossible with modern JavaScript frameworks. # 23rd October 2017, 1:51 pm

WPO Stats (via) “Case studies and experiments demonstrating the impact of web performance optimization (WPO) on user experience and business metrics.“ # 11th October 2017, 1:36 am

Web Performance: What is the best way to measure page load times on different locations of the world?

Google Analytics has a built-in “Site Speed” report with a geographical map that can help with this (under Standard Reporting > CONTENT > Site Speed > Map Overlay).

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