Numbers Every Programmer Should Know

To make it clear what to focus on when optimizing, a slide from the report “Creating software systems in Google and its lessons”:

Accessing L1 Cache	0.5 ns
Error in predicting conditional transition	5 ns
Accessing L2 Cache	7 ns
Opening / closing mutex	25 ns
Appeal to the main memory	100 ns
Compress 1 Kb fast algorithm	3,000 ns
Transfer 2Kb over the network at a speed of 1 Gb	20,000 ns
Reading 1 MB sequentially from main memory	250,000 ns
Transfer messages to / from the same data center	500,000 ns
Random access to the hard disk	10,000,000 ns
Reading 1 MB sequentially from a hard disk	20,000,000 ns
Transfer package from California to the Netherlands and back	150,000,000 ns