Jifeng Zhang zjfroot

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

A curated list of AWS resources to prepare for the AWS Certifications

A curated list of awesome AWS resources you need to prepare for the all 5 AWS Certifications. This gist will include: open source repos, blogs & blogposts, ebooks, PDF, whitepapers, video courses, free lecture, slides, sample test and many other resources.

Index:

	#Wrote by Jifeng Zhang Sun Jul 7 22:18:48 CEST 2013

	cd ~/tmp
	mkdir graphicsmagic
	cd graphicsmagic
	mkdir work
	mkdir work/deps
	#or mkdir -p work/deps

	wget http://downloads.sf.net/project/libpng/libpng15/older-releases/1.5.14/libpng-1.5.14.tar.gz

	On server:
	Install bootp, tftpd-hpa and tftp

	edit /etc/bootptab to

	client:\
	ha="00:1C:23:3C:9E:32":\
	ip=192.168.12.144:\
	gw=192.168.12.1:\
	sm=255.255.255.0:\