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

isaacs

# Hello, and welcome to makefile basics.
#
# You will learn why `make` is so great, and why, despite its "weird" syntax,
# it is actually a highly expressive, efficient, and powerful way to build
# programs.
#
# Once you're done here, go to
# http://www.gnu.org/software/make/manual/make.html
# to learn SOOOO much more.

burke

ruby-1.9.3-p327 cumulative performance patch for rbenv

This installs a patched ruby 1.9.3-p327 with various performance improvements and a backported COW-friendly GC, all courtesy of funny-falcon.

Requirements

• rbenv
• ruby-build

You will also need a C Compiler. If you're on Linux, you probably already have one or know how to install one. On OS X, you should install XCode, and brew install autoconf using homebrew.

coreyhaines

--colour
-I app

zealot128

<template lang='pug'>
  div.drop-zone(:class='{dragging: isDragging }'
    @dragover.prevent='dragover'
    @dragenter.prevent='dragover'
    @drop.prevent.stop='onDrop'
    @dragleave.prevent='dragleave')
    div(:class='{ hidden: uploadInProgress }' @click='openFileBrowser')
      slot
        i {{label}}
    input(type='file' :multiple='multiple' ref='input' style='display: none')

nybblr

Checkout the blog post for the whole story.

Setup Bower and install components:

npm install -g bower
bower install

Before deploying to Heroku, switch to the multi buildpack:

lisamelton

#!/bin/bash
#
# transcode-video.sh
#
# Copyright (c) 2013-2015 Don Melton
#

about() {
    cat <<EOF
$program 5.13 of April 8, 2015

mudge

# This goes in config/locales/en.rb (*not* en.yml)
{
  :en => {
    :time => {
      :formats => {
        :full => lambda { |time, _| "%H:%M | %A, #{time.day.ordinalize} %B %Y" }
      }
    }
  }
}

sj26

Patched ruby 1.9.3-p194 for 30% faster rails boot

What is?

This script installs a patched version of ruby 1.9.3-p194 with patches for boot-time performance improvements (#66 and #68), and runtime performance improvements (#83 and #84). It also includes the new backported GC from ruby-trunk.

Huge thanks to funny-falcon for the performance patches.

• http://github.com/ruby/ruby/pull/66
• http://github.com/ruby/ruby/pull/68

ryanb

My issues with Modules

In researching topics for RailsCasts I often read code in Rails and other gems. This is a great exercise to do. Not only will you pick up some coding tips, but it can help you better understand what makes code readable.

A common practice to organize code in gems is to divide it into modules. When this is done extensively I find it becomes very difficult to read. Before I explain further, a quick detour on instance_eval.

You can find instance_eval used in many DSLs: from routes to state machines. Here's an example from Thinking Sphinx.

class Article < ActiveRecord::Base