Gary Blankenship garyblankenship

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 cheat sheet

(C-x means ctrl+x, M-x means alt+x)

Prefix key

The default prefix is C-b. If you (or your muscle memory) prefer C-a, you need to add this to ~/.tmux.conf:

remap prefix to Control + a

Telnet

The Gearman job server supports a text-based protocol to pull information and run some administrative tasks. The following commands are supported:

workers
status
maxqueue
shutdown
version

	var parser = document.createElement('a');
	parser.href = "http://example.com:3000/pathname/?search=test#hash";

	parser.protocol; // => "http:"
	parser.hostname; // => "example.com"
	parser.port; // => "3000"
	parser.pathname; // => "/pathname/"
	parser.search; // => "?search=test"
	parser.hash; // => "#hash"
	parser.host; // => "example.com:3000"

	<?php

	/* From https://www.usps.com/send/official-abbreviations.htm */

	$us_state_abbrevs_names = array(
	'AL'=>'ALABAMA',
	'AK'=>'ALASKA',
	'AS'=>'AMERICAN SAMOA',
	'AZ'=>'ARIZONA',
	'AR'=>'ARKANSAS',

	<?php
	// Crude check. Off course this should be stored in a (memory) database. $token is an
	// access token that is provided by oauth.

	$token = $_SERVER['HTTP_X_AUTH_TOKEN'];

	if ($token == "mellon") {
	header("X-Api-User: Gandalf");
	header("X-Api-Context: Middle-Earth");
	header("Cache-Control: public, max-age=120");

	### Add those lines after *filter near the beginning of the file
	:ufw-http - [0:0]
	:ufw-http-logdrop - [0:0]



	### Add those lines near the end of the file

	### Start HTTP ###

	jQuery File Uploader (blueimp) and nginx benchmark notes.

	Hypothesis:

	Assigning the chunk size to be greater than the client_body_buffer_size will result in slower uploads and corrupt files.

	Table 1: Stability
	------------------

	The table below shows the number of successful file uploads after a random number of pause and resume operations.

	<?php

	require 'vendor/autoload.php';

	$resolver = new Illuminate\Database\ConnectionResolver;
	$resolver->setDefaultConnection('default');
	$factory = new Illuminate\Database\Connectors\ConnectionFactory;
	$connection = $factory->make(array(
	'host' => 'localhost',
	'database' => 'database',

	# ~/.gitconfig
	# Add this to your global git configuration file
	# Change phpstorm to webstorm, if you use that.

	# Diff and merge tool changes
	# Run `git difftool <directory/file>...` or `git mergetool <directory/file>...`
	[merge]
	tool = phpstorm
	[diff]
	tool = phpstorm