Aleksey Krasnobaev krasnobaev

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 shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

5 entertaining things you can find with the GitHub Search API

Let's have some command-line fun with curl, [jq][1], and the [new GitHub Search API][2].

Today we're looking for:

The hottest repositories created in the last week.
The oldest user accounts with zero followers. (So sad.)
Issue trends by language.
Clojure projects defying convention.

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.

	/*
	* object.watch polyfill
	*
	* 2012-04-03
	*
	* By Eli Grey, http://eligrey.com
	* Public Domain.
	* NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
	*/

	function interval(duration, fn){
	var _this = this
	this.baseline = undefined

	this.run = function(){
	if(_this.baseline === undefined){
	_this.baseline = new Date().getTime()
	}
	fn()
	var end = new Date().getTime()

	" Vim color scheme
	"
	" Name: railscat.vim
	" Maintainer: Jeff Kreeftmeijer
	" License: public domain
	"
	" A GUI only extended version of the Railscasts+ theme, that comes with
	" Janus [1] and is, in turn, an extension to the original Railscasts theme
	" [2], which is a port of the RailsCasts TextMate theme [3] to Vim.
	"

	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

	<?xml version="1.0" encoding="UTF-8"?>
	<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
	<plist version="1.0">
	<dict>
	<key>Label</key>
	<string>com.darkice</string>
	<key>RunAtLoad</key>
	<true/>
	<key>KeepAlive</key>
	<false/>

	var HighResolutionTimer = window.HighResolutionTimer = window.HighResolutionTimer \|\| (function() {

	var HighResolutionTimer = function(options) {
	this.timer = false;

	this.total_ticks = 0;

	this.start_time = undefined;
	this.current_time = undefined;