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

MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

jboner

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

staltz

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.

---

chetan

YARD CHEATSHEET http://yardoc.org

May 2020 - updated fork: https://gist.github.com/phansch/db18a595d2f5f1ef16646af72fe1fb0e

cribbed from http://pastebin.com/xgzeAmBn

Templates to remind you of the options and formatting for the different types of objects you might want to document using YARD.

Modules

dergachev

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

atenni

Problem: When linking to the raw version of a gist, the link changes with each revision.

Solution:

To return the first file from a gist: https://gist.github.com/[gist_user]/[gist_id]/raw/

• Example: https://gist.github.com/atenni/5604522/raw/
• Works even when you change the filename.

To get a file from multi–file gist: https://gist.github.com/[gist_user]/[gist_id]/raw/[file_name]

john2x

Clojure Destructuring Tutorial and Cheat Sheet

(Related blog post)

Simply put, destructuring in Clojure is a way extract values from a datastructure and bind them to symbols, without having to explicitly traverse the datstructure. It allows for elegant and concise Clojure code.

Vectors and Sequences

pietern

# Author: Pieter Noordhuis
# Description: Simple demo to showcase Redis PubSub with EventMachine
#
# Update 7 Oct 2010:
# - This example does *not* appear to work with Chrome >=6.0. Apparently,
#   the WebSocket protocol implementation in the cramp gem does not work
#   well with Chrome's (newer) WebSocket implementation.
#
# Requirements:
# - rubygems: eventmachine, thin, cramp, sinatra, yajl-ruby

mathiasbynens

#!/bin/bash

if [ "$1" = "-h" -o "$1" = "--help" -o -z "$1" ]; then cat <<EOF
appify v3.0.1 for Mac OS X - http://mths.be/appify
Creates the simplest possible Mac app from a shell script.

Appify takes a shell script as its first argument:

    `basename "$0"` my-script.sh