Appendix C. Numbers Everyone Should Know
Table C-1 lists the numbers everyone should know, also known as “Jeff Dean’s 12 Numbers.”
| Computer architecture operation | Duration (in nanoseconds) |
|---|---|
| L1 cache reference | 0.5 |
| Branch mispredict | 5 |
| L2 cache reference | 7 |
| Mutex lock/unlock | 100 |
| Main memory reference | 100 |
| Compress 1 KB with Zippy | 10,000 |
| Send 2 KB over 1 Gbps network | 20,000 |
| Read 1 MB sequentially from memory | 250,000 |
| Roundtrip within same datacenter | 500,000 |
| Disk seek | 10,000,000 |
| Read 1 MB sequentially from network | 10,000,000 |
| Read 1 MB sequentially from disk | 30,000,000 |
| Send packet CA->Netherlands->CA | 150,000,000 |
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