Sergey Lysenko lysenko-sergey-developer

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

tmux cheat sheet

(C-x means ctrl+x, M-x means alt+x)

Prefix key

The default prefix is C-b. If you (or your muscle memory) prefer C-a, you need to add this to ~/.tmux.conf:

remap prefix to Control + a

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

Commit Message Conventions

These rules are adopted from the AngularJS commit conventions.

Goals
Generating CHANGELOG.md
- Recognizing unimportant commits
- Provide more information when browsing the history
Format of the commit message
Subject line

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

	<html>
	<body>

	<!-- really dirty! this is just a test drive ;) -->

	<script type="text/javascript" src="https://raw.github.com/mozilla/pdf.js/gh-pages/build/pdf.js"></script>
	<script type="text/javascript">
	function renderPDF(url, canvasContainer, options) {

	var options = options \|\| { scale: 1 };

	/**
	* CSS Animated Repeating Gradient
	*/
	body {
	background: repeating-linear-gradient(-45deg,red,red 20px,blue 20px,blue 40px);
	background-size:56px 56px;/* This is unique for this background, need to find a pattern and develop a formula */
	background-position-x:0%;
	-webkit-animation:'slide' 20s infinite linear forwards;

	}

	(defroutes app
	(GET "/" [] "<h1>Index route</h1>")
	(route/not-found "<h1>Page not found</h1>"))

	(defn fake-request [routes uri method & params]
	(let [localhost "127.0.0.1"]
	(routes {:server-port 80
	:server-name localhost
	:remote-addr localhost
	:uri uri

	<script src="http://cdnjs.cloudflare.com/ajax/libs/processing.js/1.4.1/processing-api.min.js"></script><html>
	<!--
	Created using jsbin.com
	Source can be edited via http://jsbin.com/pdfjs-helloworld-v2/8598/edit
	-->
	<body>
	<canvas id="the-canvas" style="border:1px solid black"></canvas>
	<input id='pdf' type='file'/>

	<!-- Use latest PDF.js build from Github -->