Latency numbers every programmer should know with 中文常用单位注释

latency.txt

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微秒
Send 2K bytes over 1 Gbps network   20,000 ns // 20微秒
Read 1 MB sequentially from memory  250,000 ns // 0.25毫秒
Round trip within same datacenter   500,000 ns // 0.5毫秒
Disk seek                           10,000,000 ns // 10毫秒
Read 1 MB sequentially from disk    20,000,000 ns // 20毫秒
Send packet CA->Netherlands->CA     150,000,000 ns // 150毫秒

By Jeff Dean (http://research.google.com/people/jeff/):