Latency Comparison Numbers -------------------------- L1 cache reference 0.5 ns Branch mispredict 5 ns L2 cache reference 7 ns 14x L1 cache Mutex lock/unlock 25 ns Main memory reference 100 ns 20x L2 cache, 200x L1 cache Compress 1K bytes with Zippy 10,000 ns 10 us Send 1 KB bytes over 1 Gbps network 10,000 ns 10 us Read 4 KB randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD Read 1 MB sequentially from memory 250,000 ns 250 us Round trip within same datacenter 500,000 ns 500 us Read 1 MB sequentially from SSD* 1,000,000 ns 1,000 us 1 ms ~1GB/sec SSD, 4X memory Disk seek 10,000,000 ns 10,000 us 10 ms 20x datacenter roundtrip Read 1 MB sequentially from 1 Gbps 10,000,000 ns 10,000 us 10 ms 40x memory, 10X SSD Read 1 MB sequentially from disk 30,000,000 ns 30,000 us 30 ms 120x memory, 30X SSD Send packet CA->Netherlands->CA 150,000,000 ns 150,000 us 150 ms Notes ----- 1 ns = 10^-9 seconds 1 us = 10^-6 seconds = 1,000 ns 1 ms = 10^-3 seconds = 1,000 us = 1,000,000 ns
基于上述数字的指标：
- 从磁盘以 30 MB/s 的速度顺序读取
- 以 100 MB/s 从 1 Gbps 的以太网顺序读取
- 从 SSD 以 1 GB/s 的速度读取
- 以 4 GB/s 的速度从主存读取
- 每秒能绕地球 6-7 圈
- 数据中心内每秒有 2,000 次往返
延迟数可视化
标签：10,MB,us,访问,000,SSD,ns,资源,延迟 From： https://www.cnblogs.com/raorao1994/p/17922032.html