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

magicdude4eva

Add the following in .zshrc:

...
plugins=(osx git zsh-autosuggestions zsh-syntax-highlighting zsh-nvm docker kubectl)
...

### Fix slowness of pastes with zsh-syntax-highlighting.zsh
pasteinit() {
  OLD_SELF_INSERT=${${(s.:.)widgets[self-insert]}[2,3]}
  zle -N self-insert url-quote-magic # I wonder if you'd need `.url-quote-magic`?

steven2358

FFmpeg cheat sheet

A list of useful commands for the FFmpeg command line tool.

Download FFmpeg: https://www.ffmpeg.org/download.html

Full documentation: https://www.ffmpeg.org/ffmpeg.html

Basic conversion

TimJDFletcher

Forward GnuPG agent from macOS to Linux

On the remote machine

Run gpg once as your to create the directory structure

gpg --list-keys

For headless systemd based hosts

DaniSancas

Neo4j Tutorial

Fundamentals

Store any kind of data using the following graph concepts:

• Node: Graph data records
• Relationship: Connect nodes (has direction and a type)
• Property: Stores data in key-value pair in nodes and relationships
• Label: Groups nodes and relationships (optional)

lisawolderiksen

Using Git Commit Message Templates to Write Better Commit Messages

The always enthusiastic and knowledgeable mr. @jasaltvik shared with our team an article on writing (good) Git commit messages: How to Write a Git Commit Message. This excellent article explains why good Git commit messages are important, and explains what constitutes a good commit message. I wholeheartedly agree with what @cbeams writes in his article. (Have you read it yet? If not, go read it now. I'll wait.) It's sensible stuff. So I decided to start following the

JPvRiel

Overview

Some notes about:

• Explaining why current day Linux memory swap thrashing still happens (as of 2016).
• Mitigating "stop the world" type thrashing issues on a Linux workstation when it's under high memory pressure and where responsiveness is more important than process completion.
• Prioritizing and limiting memory use.
• Older ulimit versus newer CGroup options.

These notes assume some basic background knowledge about memory management, ulimits and cgroups.

rauchg

require-from-twitter

Since Twitter doesn't have an edit button, it's a suitable host for JavaScript modules.

How to use

Source tweet: https://twitter.com/rauchg/status/712799807073419264

const leftPad = await requireFromTwitter('712799807073419264');

gdvalle

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\Sessions\monokai]
"Colour21"="255,255,255"
"Colour20"="245,222,179"
"Colour19"="200,240,240"
"Colour18"="0,217,217"
"Colour17"="179,146,239"
"Colour16"="174,129,255"
"Colour15"="122,204,218"

nicowilliams

I recently happened upon a very interesting implementation of popen() (different API, same idea) called popen-noshell using clone(2), and so I opened an issue requesting use of vfork(2) or posix_spawn() for portability. It turns out that on Linux there's an important advantage to using clone(2). I think I should capture the things I wrote there in a better place. A gist, a blog, whatever.

This is not a paper. I assume reader familiarity with fork() in particular and Unix in general, though, of course, I link to relevant wiki pages, so if the unfamiliar reader is willing to go down the rabbit hole, they should be able to come ou