Nur Rony nurrony

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

While attempting to explain JavaScript's reduce method on arrays, conceptually, I came up with the following - hopefully it's helpful; happy to tweak it if anyone has suggestions.

Intro

JavaScript Arrays have lots of built in methods on their prototype. Some of them mutate - ie, they change the underlying array in-place. Luckily, most of them do not - they instead return an entirely distinct array. Since arrays are conceptually a contiguous list of items, it helps code clarity and maintainability a lot to be able to operate on them in a "functional" way. (I'll also insist on referring to an array as a "list" - although in some languages, List is a native data type, in JS and this post, I'm referring to the concept. Everywhere I use the word "list" you can assume I'm talking about a JS Array) This means, to perform a single operation on the list as a whole ("atomically"), and to return a new list - thus making it much simpler to think about both the old list and the new one, what they contain, and

Quick Steps to Configure Amazon AutoScaling

Setup Environment and Credentials

aptitude install openjdk-6-jre-headless
cat <<-ACCESS > <PATH_TO_CREDENTIAL_FILE>
AWSAccessKeyId=<YOUR_KEY_ID>

AWSSecretKey=

	worker_processes 4;

	events {
	worker_connections 1024;
	}

	http {
	default_type application/octet-stream;
	log_format main '$remote_addr - $remote_user [$time_local] "$request" '
	'$status $body_bytes_sent "$http_referer" '

	var Col = require('react-bootstrap/lib/Col')
	var PageHeader = require('react-bootstrap/lib/PageHeader')
	var React = require('react')
	var Row = require('react-bootstrap/lib/Row')
	var {connect} = require('react-redux')
	var {reduxForm} = require('redux-form')

	var DateInput = require('./DateInput')
	var FormField = require('./FormField')
	var LoadingButton = require('./LoadingButton')

	angular.module('cropAndUpload', [
	'angularFileUpload',
	'ngImgCrop'
	])

	#!/usr/bin/env ruby

	require 'faraday'
	require 'json'
	require 'gitlab'

	module Redmine
	Host = nil
	APIKey = nil

	var page = require('webpage').create();

	page.onConsoleMessage = function (msg) {
	console.log('From Page Console: '+msg);
	};

	page.onInitialized = function() {
	page.evaluate(function () {
	"use strict";
	//The Referrer we want to set

	# to generate your dhparam.pem file, run in the terminal
	openssl dhparam -out /etc/nginx/ssl/dhparam.pem 2048

	'use strict';

	/**
	* Follow these steps to configure the webhook in Slack:
	*
	* 1. Navigate to https://<your-team-domain>.slack.com/services/new
	*
	* 2. Search for and select "Incoming WebHooks".
	*
	* 3. Choose the default channel where messages will be sent and click "Add Incoming WebHooks Integration".