He found that the more HTTP client requests he did, the more memory his Node process would consume, but it was really slow.
[...] Then I ran Node with UMEM_DEBUG set to record various important information about the memory allocations
[...] Every hour, it grabbed the output of pmap -x and a core file and stored those in Joyent Manta
[...] In MDB there's a particularly helpful command ::findleaks that will show you the memory addresses and the stack traces for leaked memory, not unlike using valgrind, but without all the performance penalty.
[...] At this point we knew that we were looking for something in v0.10 that called MakeCallback but that didn't first have a HandleScope on the stack. I then worked up this simple DTrace script.
All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.
Avec ce tutoriel vous verez comment rendre votre site web plus rapide : de l’optimisation des requêtes, à l’affichage de la page, en passant par la génération des pages web et l’affichage correct des pages sur tous les terminaux.
tl;dr:
Lighthouse is an open-source, automated tool for improving the quality of web pages. You can run it against any web page, public or requiring authentication. It has audits for performance, accessibility, progressive web apps, and more.
You can run Lighthouse in Chrome DevTools, from the command line, or as a Node module.
Source code of the rules used
Checklists pour:
bLazy is a lightweight script for lazy loading and multi-serving images, iframes, videos and more (less than 1.4KB minified and gzipped). It’s written in pure JavaScript why it doesn’t depend on 3rd-party libraries such as jQuery. It lets you lazy load and multi-serve your images so you can save bandwidth and server requests. The user will have faster load times and save data usage if he/she doesn't browse the whole page.
It's working in all modern browsers including IE7+.
Used by shaarli
There are many common pitfalls when it comes to writing memory-efficient and fast code. JavaScript engines such as Google’s V8 (Chrome, Node) are specifically designed for the fast execution of large JavaScript applications.
Specifically: advices on loading third party JS :
third-party script is slowing down your page load, you have several options to improve performance:
async
or defer
attribute to avoid blocking document parsing.<link rel=preconnect>
or <link rel=dns-prefetch>
to perform a DNS lookup for domains hosting third-party scripts.iframe
A resource for developers looking to put HTML5 to use today, including information on specific features and when to use them in your apps.