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

predominant

#!/bin/bash

##
## Commit configuration files.
##
if [ ! -d /etc/.git ]; then
	cd /etc
	git init
	git config user.name "Server Administrator"
	git config user.email "root@localhost"

pjkelly

# Uninstall any pre-existing packaged
# versions of phpunit
sudo apt-get remove phpunit

# Install pear via apt-get
sudo apt-get install php-pear

# Update existing pear channels
sudo pear channel-update pear.php.net