Google engineer Jeff Dean first listed it in his ppt document on distributed systems, and it is quoted a lot everywhere.
1 nanosecond equals one billionth of a second, = 10 ^ -9 seconds
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Numbers Everyone Should Know
| L1 cache reference reads the CPU's first-level cache | 0.5 ns |
| Branch mispredict (transfer, branch prediction) | 5 ns |
| L2 cache reference reads the CPU's second-level cache | 7 ns |
| Mutex lock/unlock mutex lock\unlock | 100 ns |
| Main memory reference read memory data | 100 ns |
| Compress 1K bytes with Zippy 1k bytes compression | 10,000 ns |
| Send 2K bytes over 1 Gbps network Send 2K bytes over 1Gbps network | 20,000 ns |
| Read 1 MB sequentially from memory Read 1MB sequentially from memory | 250,000 ns |
| Round trip within same datacenter Round trip from one datacenter, ping | 500,000 ns |
| Disk seek Disk seek | 10,000,000 ns |
| Read 1 MB sequentially from network Read 1 MB of data sequentially from the network | 10,000,000 ns |
| Read 1 MB sequentially from disk Read 1MB from the disk | 30,000,000 ns |
| Send packet CA->Netherlands->CA One remote access for one packet | 150,000,000 ns |
Reposted from: https://www.cnblogs.com/liqiu/p/3211746.html