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

mattetti

#!/usr/local/bin/macruby

# Copyright (c) 2009 Matt Aimonetti
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

mrflip

Max Battery Life Checklist

Here is a checklist to follow if you want maximum battery life -- for instance if you're about to get on a long plane flight.

Low power use checklist

With power connected:

rmhall

My iTunes Match Track upgrading and process info:

If you have less than 25,000 tracks:

1. First let iTunes Match do its things and find all possible matches in your library and finish uploading any non-matching tracks.
2. Once its done, make a new Smart Playlist (I made a folder for all my Smart iTunes Match Related Playlists)
Name this one: iCloud-Upgradeable
Criteria:
MATCH ALL:
Bit Rate is less than 256kbps

gruber

use strict;
use warnings;
use URI::Escape qw(uri_escape_utf8);
use open IO  => ":utf8",		# UTF8 by default
		  ":std";				# Apply to STDIN/STDOUT/STDERR

my $query = do { local $/; <> };
$query =~ s/^\s+//g;
$query =~ s/\s+$//g;

gruber

The regex patterns in this gist are intended to match any URLs,
including "mailto:[email protected]", "x-whatever://foo", etc. For a
pattern that attempts only to match web URLs (http, https), see:
https://gist.github.com/gruber/8891611


# Single-line version of pattern:

(?i)\b((?:[a-z][\w-]+:(?:/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’]))