Simon Elsbrock elsbrock

Stevey's Google Platforms Rant

I was at Amazon for about six and a half years, and now I've been at Google for that long. One thing that struck me immediately about the two companies -- an impression that has been reinforced almost daily -- is that Amazon does everything wrong, and Google does everything right. Sure, it's a sweeping generalization, but a surprisingly accurate one. It's pretty crazy. There are probably a hundred or even two hundred different ways you can compare the two companies, and Google is superior in all but three of them, if I recall correctly. I actually did a spreadsheet at one point but Legal wouldn't let me show it to anyone, even though recruiting loved it.

I mean, just to give you a very brief taste: Amazon's recruiting process is fundamentally flawed by having teams hire for themselves, so their hiring bar is incredibly inconsistent across teams, despite various efforts they've made to level it out. And their operations are a mess; they don't real

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 shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

	#
	# mmm m m mmm mmm mmm mmmmm mmm
	# " # "m m m" #" # # " #" "# # # # #" #
	# m"""# #m#m# #"""" """m # # # # # #""""
	# "mm"# # # "#mm" "mmm" "#m#" # # # "#mm"
	#
	# nginx configuration For Ruby/Rack web applications
	#
	# Cooked up with style, care and a bit of secret
	# nerdy spice. :-)

	#! /bin/sh
	#
	## Tested on Linux Debian 5.0 (Lenny)
	#
	# OK I know this is nothing new/special.
	# If you've always configured your LBs a certain way, you might have to use this method instead.
	#
	# Scenario: High-availability setup with 2 HAProxy/Keepalived load-balancers on IPv6
	#
	# Problem: HAProxy won't start (cannot bind socket) because the virtual IPv6 address is not assigned

	window.onload = function() {

	var v0 = new Vertex("0");
	var v1 = new Vertex("1");
	var v2 = new Vertex("2");
	var v3 = new Vertex("3");
	var v4 = new Vertex("4");
	var v5 = new Vertex("5");
	var v6 = new Vertex("6");
	var v7 = new Vertex("7");

	// Lefalet shortcuts for common tile providers - is it worth adding such 1.5kb to Leaflet core?

	L.TileLayer.Common = L.TileLayer.extend({
	initialize: function (options) {
	L.TileLayer.prototype.initialize.call(this, this.url, options);
	}
	});

	(function () {

	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"

	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