hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

Rich-Harris

Stuff I wish I'd known sooner about service workers

I recently had several days of extremely frustrating experiences with service workers. Here are a few things I've since learned which would have made my life much easier but which isn't particularly obvious from most of the blog posts and videos I've seen.

I'll add to this list over time – suggested additions welcome in the comments or via twitter.com/rich_harris.

Use Canary for development instead of Chrome stable

Chrome 51 has some pretty wild behaviour related to console.log in service workers. Canary doesn't, and it has a load of really good service worker related stuff in devtools.

veekaybee

ChatGPT Resources

Context

ChatGPT appeared like an explosion on all my social media timelines in early December 2022. While I keep up with machine learning as an industry, I wasn't focused so much on this particular corner, and all the screenshots seemed like they came out of nowhere. What was this model? How did the chat prompting work? What was the context of OpenAI doing this work and collecting my prompts for training data?

I decided to do a quick investigation. Here's all the information I've found so far. I'm aggregating and synthesizing it as I go, so it's currently changing pretty frequently.

Model Architecture

paulirish

Screencapture and animated gifs

I say "animated gif" but in reality I think it's irresponsible to be serving "real" GIF files to people now. You should be serving gfy's, gifv's, webm, mp4s, whatever. They're a fraction of the filesize making it easier for you to deliver high fidelity, full color animation very quickly, especially on bad mobile connections. (But I suppose if you're just doing this for small audiences (like bug reporting), then LICEcap is a good solution).

Capturing (Easy)

1. Launch quicktime player
2. do Screen recording

radum

Charles Proxy Map Remote over HTTP or HTTPS

The Map Remote tool changes the request location, per the configured mappings, so that the response is transparently served from the new location as if that was the original request.

HTTP

Using this feature for http resources does't require anything else apart from just configuring your Map Remote entry.

Always make sure you are clearing your cache before you test. Even if Charles is configured properly you might not see the changes unless the browser gets the resource again from the server and not for its local cache.

stevekinney

Web Performance

Requirements

• You need to have the latest version of Node. Preferably, you're using 9.8.0, but the latest LTS should work as well.
• You should have npx installed using npm install -g npx.
• Install the React Developer Tools.

Repositories

sorenlouv

function mySlowFunction(baseNumber) {
	console.time('mySlowFunction');
	let result = 0;	
	for (var i = Math.pow(baseNumber, 7); i >= 0; i--) {		
		result += Math.atan(i) * Math.tan(i);
	};
	console.timeEnd('mySlowFunction');
}

mySlowFunction(8); // higher number => more iterations => slower

O-Zone

(function (window) {
  var transitions = {
    'transition': 'transitionend',
    'WebkitTransition': 'webkitTransitionEnd',
    'MozTransition': 'transitionend',
    'OTransition': 'otransitionend'
  },
  elem = document.createElement('div');
 
  for(var t in transitions){

radum

Articles

Performance API

// https://github.com/WICG/paint-timing
performance.getEntries();
performance.getEntriesByType('paint');

// Calculate the time it spends to run something

wesbos

#!/bin/bash
files=$(git diff --cached --name-only | grep '\.jsx\?$')

# Prevent ESLint help message if no files matched
if [[ $files = "" ]] ; then
  exit 0
fi

failed=0
for file in ${files}; do