google 工程师Jeff Dean 首先在他关于分布式系统的ppt文档列出来的,处处被引用的不少。缓存
1s = 10^3ms = 10^6μs = 10^9ns网络
1秒 = 1千毫秒 = 1百万微秒 = 10亿纳秒分布式
Numbers Everyone Should Knowip
描述 | 纳秒ns | 微秒μs | 毫秒ms | 秒s |
L1 cache reference 读取CPU的一级缓存 | 0.5 | - | - | - |
Branch mispredict(转移、分支预测) | 5 | - | - | - |
L2 cache reference 读取CPU的二级缓存 | 7 | - | - | - |
Mutex lock/unlock 互斥锁\解锁 | 100 | 0.1 | - | - |
Main memory reference 读取内存数据 | 100 | 0.1 | - | - |
Compress 1K bytes with Zippy 1k字节压缩 | 10,000 | 10 | - | - |
Send 2K bytes over 1 Gbps network 在1Gbps的网络上发送2k字节 | 20,000 | 20 | - | - |
Read 1 MB sequentially from memory 从内存顺序读取1MB | 250,000 | 250 | 0.25 | - |
Round trip within same datacenter 从一个数据中心往返一次,ping一下 | 500,000 | 500 | 0.5 | - |
Disk seek 磁盘搜索 | 10,000,000 | 10,000 | 10 | 0.01 |
Read 1 MB sequentially from network 从网络上顺序读取1兆的数据 | 10,000,000 | 10,000 | 10 | 0.01 |
Read 1 MB sequentially from disk 从磁盘里面读出1MB | 30,000,000 | 30,000 | 30 | 0.03 |
Send packet CA->Netherlands->CA 一个包的一次远程访问 | 150,000,000 | 150,000 | 150 | 0.15 |