Web performance: Cache efficiency exercise. Speed is a consideration for any website, whether it's for the local barbershop or Wikipedia, with its huge repository of knowledge. It's a feature that shouldn't be ignored. This is why caching is important — a great way to make websites faster is to save parts of them so they don't have to be calculated or downloaded again on the next visit. My team was recently having a discussion about the parts of facebook.com that are currently uncached, and the question came up: What is the efficiency of the cache since, at Facebook, we release new code twice a day? Are we releasing new code too often to benefit from having resources in the browser cache? In searching for an answer, we found a study on Yahoo's Performance Research blog that looked at the impact of the browser cache on webpage performance. We were surprised and saddened to see the results: 20% of all page views were coming in with an empty cache.
Re-creating the study Cache-Control: private, max-age=0Pragma: no-cache Study Results. Ludicrously Fast Page Loads - A Guide for Full-Stack Devs. Summary: Your website is slow, but the backend is fast. How do you diagnose performance issues on the frontend of your site? We'll discuss everything involved in constructing a webpage and how to profile it at sub-millisecond resolution with Chrome Timeline, Google's flamegraph-for-the-browser. (4428 words/22 minutes) Server response times, while easy to track and instrument, are ultimately a meaningless performance metric from an end-user perspective. Actual end-user response to the word 'microservices'. End-users don't care how fast your super-turbocharged bare-metal Node.js server is - they care about the page being completely loaded as fast as possible. Well, what does constructing a webpage actually require?
Server response times can easily balloon without proper use of caching, both at the application and HTTP layers. So what's a good, performance-minded full stack developer to do? Enter Chrome Timeline My number one front-end performance tool is Chrome Timeline. Receiving the HTML. Evaluating network performance. The Network panel records information about each network operation in your application, including detailed timing data, HTTP request and response headers, cookies, WebSocket data, and more. The Network panel helps you answer questions about the network performance of your web application, such as: Which resource had the slowest time to first byte? Which resources took the longest time to load (duration)? Who initiated a particular network request? How much time was spent in the various network phases for a particular resource? The Network panel uses the Resource Timing API, a JavaScript API that provides detailed network timing data for each loaded resource.
For example, the API can tell you precisely when the HTTP request for an image started, and when the image's final byte was received. The API is available to any web page, not just DevTools. Try this: open the JavaScript console on the current page, enter the following at the prompt, and hit Return: window.performance.getEntries()[0] Self-Hosting Google Web Fonts | Mario Ranftl. Let’s get this straight: The effort to host Google web fonts on your own server is immense! First of all you need to download all .eot, .woff, .ttf and .svg files, then copy them onto your server and finally paste a CSS snippet. Sounds easy? Well it could be, if Google would actually provide any direct links to download these files and a customized CSS for self-hosting them. To fix this problem without using font generation services like Font Squirrel, I decided to publish a little service called google-webfonts-helper.
The service uses Google’s font API to retrieve a list of all available web fonts and fetches links to the .eot, .woff, .ttf and .svg files by parsing their hosted CSS files (and faking the User-Agent to get them). Internally, I’m using the (M)EAN stack (without MongoDB) as I really needed some practice with Angular and Express. Please leave comments on Hackernews or here if you have any suggestions and take a look at the code on GitHub. Linking to jQuery: Always Reference a Specific Version. If you use jQuery, then you probably have a URL in a <script> tag like this in your source code: CDN-hosted. Minified. Specific version. Very good. Of course, if you’re one of the cool kids, then you might be doing the following, as taken from HTML5 Boilerplate: <script src="//ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script><script>window.jQuery || document.write('<script src="js/jquery-1.7.2.min.js"><\/script>')</script> This ensures that if an edge-case scenario occurs in which the CDN-hosted jQuery is momentarily down, you fall back to a locally hosted version.
So all is good. The Wrong Ways But I get the feeling that a few less experienced jQuery users are referencing jQuery like this: Notice the less specific version number — “1.7” instead of “1.7.2”. Or, even worse: Or, worst of all: S Content Delivery Network: You Got Served! In 2013, MaxCDN joined the jQuery Foundation and stepped up to provide Content Delivery Network (CDN) services for the jQuery CDN at code.jquery.com. Files can now be requested through both HTTP and HTTPS (SSL) protocols, either to download to your own servers or to use directly on production web sites. MaxCDN’s infrastructure can reliably deliver jQuery files through a worldwide high-speed collection of servers to minimize round-trip time. Why a CDN is Useful to Developers The obvious benefit is that the MaxCDN network is much faster than the average server, and geographically distributed so that round-trip times are kept low.
Yet there is another subtle benefit. Why a CDN is Useful to jQuery Projects jQuery projects serve out a huge number of bytes, especially on days when a project makes a new release. Serving Billions of Files, Trillions of Bytes We thought we were serving a lot of files, but some statistics from MaxCDN really drive home the point. Counting on the CDN. Optimizing the Critical Rendering Path - Velocity SC 2013 - Google Slides. Image Optimization, Part 4: Progressive JPEG…Hot or Not? - YUI Blog. WebPagetest - Website Performance and Optimization Test. HTTP Archive Viewer 2.0.16. Paste HAR log into the text box below and press the Preview button.Or drop *.har file(s) anywhere on the page (if your browser supports that). HAR Log Examples Inline scripts block - Inline scripts block the page load. Blocking time - Impact of a limit of max number of parallel connections.
Browser cache - Impact of the browser cache on page load (the same page loaded three times). Single page - Single page load (empty cache). HAR Logs Online You can also preview any HAR file (in JSONP format) that is available online by using inputUrl parameter (see more in the About tab): This viewer supports HAR 1.2 (see the About tab). Measuring the speed of resource loading with JavaScript and HTML5 | Andrea Trasatti's tech notes and more. This is a follow up article to Measuring site performance with JavaScript on mobile , I suggest you read it before you continue.
In the previous article I talked about the Navigation Timing spec, here I will talk about the Performance Timeline and Resource Timing specs and how they work in IE10, the first browser to implement them. I created a page that shows some of the data available and a library that generates a HAR that you can later analyse. Showing basic performance details of page resources The Performance Timeline is a spec that extends the Performance interface defined in the Navigation Timing spec and adds a new interface called .
The new additions give to developers a quick overview of the performance of each resource that composes the page and the order in which each resource was loaded. Once you have a list of the resources that the browser has loaded you can further explore the details of each HTTP request. Start time and duration of each resource How does it work? Resources. Make the Web Faster. Optimize Start Render Time - web page optimization of start rendering times. The start render time is the moment something first displays on the user's screen.
The web page goes from a blank white screen and changes. It doesn't necessarily have to be content; a logo, or text, it could be a colored background or a search box. Human-computer interaction (HCI) guidelines recommend a 1-2 second start render time. Giving the user visual feedback that something is happening behind the screens shows the users that the site is responsive. Users can plan, anticipate and "attune" to consistent response times when browsing web pages. The average web page has grown inexorably as bandwidth has increased. The average web page has over 100 objects and is 1200K in size (HTTPArchive.org).